GIFT OF 
 
 Zooli dept. 
 
 BIOLOGY 
 
PRACTICAL ZOOLOGY 
 
 AN ELEMENTARY TEXT-BOOK TREATING OF 
 
 THE STRUCTURE, LIFE HISTORY, AND 
 
 RELATIONS OF ANIMALS 
 
 BY 
 
 ALVIN pAVISON, A.M., PH.D. 
 
 Professor of Biology in Lafayette College; Fellow of the American 
 
 Association for the Advancement of Science; 
 
 Author of Mammalian Anatomy, etc. 
 
 NEW YORK .-. CINCINNATI .-. CHICAGO 
 AMERICAN BOOK COMPANY 
 
LIBRAW 
 
 G 
 
 COPYBIGHT, 1906, 
 BY 
 
 ALV1N DAVISON 
 
 Davison's Zoology 
 w. P. 7 
 
PREFACE 
 
 IN most cases where only one of the two biological 
 branches is included in the curriculum of a secondary 
 school, botany is chosen. This is probably due not only 
 to the fact that few teachers have studied zoology, but 
 also to the difficulties incident to the teaching of the sub- 
 ject and the impractical kind of zoology to which too many 
 teachers have been introduced. In many schools the 
 college graduate has inflicted on his pupils in their lower 
 teens the zoology adapted to college students. Laborious 
 dissections, permitting the details of structure to be noted 
 and wearisome drawings to be made, may be of value to 
 the few, but render injustice to many. 
 
 The plan of teaching the biological sciences lately in 
 many schools has sacrificed the acquisition of important 
 information and the training of the powers of reflection 
 and expression to the cultivation of the powers of observa- 
 tion and the teaching of drawing. The average individual 
 cares little about the names of the parts of the crayfish's 
 legs or the veins in the wings of insects, but he must be 
 stupid indeed who is not interested hi the interdependence 
 of species, the part played by insects in the transmission of 
 disease, the marvelous life history of the creatures with 
 which he comes into daily contact, and the meaning of the 
 animal architecture so common in the crowded city as well 
 as by the unfrequented wayside. It is far more important 
 
 5 
 
 255377 
 
PREFACE 
 
 that the pupils should become acquainted with some of the 
 important works on zoology and thus learn where infor- 
 mation may be secured on the topics in which they may 
 be interested, than to spend much time in memorizing 
 terms and recording details never to be of any service in 
 later life. The most effective mental discipline is experi- 
 enced by him who investigates any assigned subject by 
 personal observations of the animals concerned, and by 
 consulting the several pamphlets and books treating of the 
 subject, and then after arranging his information in logical 
 order presents it to the rest of the class in language and 
 drawings sufficiently clear to be comprehended. 
 
 The growing custom of allowing the work recorded in 
 the note book to take the place of oral recitation is a bad 
 one. The mental discipline and exhilaration resulting 
 from the expression of one's matured thoughts before 
 his associates can be secured in no other way. A number 
 of questions should be assigned the class for each recita- 
 tion, in addition to one or two special topics to be reported 
 on by one or two members allowed a week or more to in- 
 vestigate them. In some schools the instructor will find 
 it wise to omit certain subjects discussed in the text owing 
 to the need of time for more extended laboratory work and 
 the investigation of topics in which his community may 
 be specially interested. 
 
 A comparatively small amount of laboratory work is 
 indicated, and the animals to be used are such as may be 
 secured almost anywhere. Detailed directions concern- 
 ing the examination and dissection of specimens have been 
 largely omitted in order that the pupil may have some op- 
 portunity to think for himself. Moreover, different schools 
 
PREFACE 7 
 
 are unable to carry on the laboratory work on the same 
 animals with the same degree of thoroughness. Those 
 who are unable to secure any material for study will find 
 in the illustrations excellent substitutes, but it is hoped 
 that every teacher will strive to afford his pupils that 
 mental stimulus and specially valuable mind culture re- 
 sulting from a face to face acquaintance with animal life. 
 At best, it is impossible to secure all the material necessary 
 to demonstrate the ideas to be taught, and therefore 
 numerous illustrations have been introduced. Much time 
 and expense have been given to the preparation of the 
 photographs, which can be relied on as representing facts 
 more accurately than drawings, and approaching as nearly 
 as possible to nature itself. 
 
 The subject matter has been so treated as to adapt the 
 book to schools giving either a half or whole year to the 
 study of zoology. Those preferring it can begin the study 
 with the Protozoa and proceed to the higher forms, instead 
 of following the order given in the text, as the chapters in 
 Parts I and II are so written as to be largely independent 
 of each other. Teachers having only a half year for 
 Zoology will perhaps find it wise to omit certain chapters 
 in order that the time which ought to be spent in studying 
 the animals shall not be devoted to the study of the 
 book. It is not expected that most schools will be able 
 to give careful attention to all the subjects treated, but 
 the numerous forms and phases of animal life have been 
 presented in order to allow some choice on the part of 
 the teacher desiring to emphasize special features of 
 zoological study. 
 
 Mr. D, S, Hartline, of the State Normal School at Blooms- 
 
8 PREFACE 
 
 burg, has rendered me efficient assistance in reading and 
 criticising the entire manuscript, while numerous other 
 students of nature to whom credit is given in the text have 
 contributed drawings, photographs, and suggestions, add- 
 ing much to the value of the book. 
 
 ALVIN DAVISON. 
 
 LAFAYETTE COLLEGE, EASTON, PA. 
 
CONTENTS 
 
 INTRODUCTION 
 
 PAGE 
 
 METHODS, EQUIPMENT, ETC 11 
 
 CLASSIFICATION . 25 
 
 PART I 
 The Arthropoda : Segmented Forms with Jointed Legs 
 
 1. ORTHOPTERA 30 
 
 2. DlPTERA 39 
 
 3. HYMENOPTERA 52 
 
 4. LEPIDOPTERA 68 
 
 5. HEMIPTERA 91 
 
 6. COLEOPTERA . 107 
 
 7. NEUROPTERA, EPHEMERIDA, AND ODONATA ...... 116 
 
 8. ARACHNIDA AND MYRIAPODA 125 
 
 9. CRUSTACEA 133 
 
 PART II 
 The Anarthropoda: Invertebrates without Jointed Legs 
 
 10. MOLLUSCA 142 
 
 11. VERMES 150 
 
 12. ECHINODERMATA 161 
 
 13. CCELENTERATA AND PoRIFERA 167 
 
 14. PROTOZOA : ONE-CELLED MICROSCOPIC ANIMALS .... 178 
 
 9 
 
10 CONTENTS 
 
 PART III 
 Vertebrate 
 
 PAGE 
 
 15. PISCES 185 
 
 16. AMPHIBIA 199 
 
 17. REPTILIA 211 
 
 18. AVES 226 
 
 19. MAMMALIA 261 
 
 PART IV 
 Animal Life 
 
 20. FROM EGG TO ADULT 293 
 
 21. SENSES OF ANIMALS 303 
 
 22. PROTECTION FROM ENEMIES 310 
 
 23. PARASITISM 323 
 
 24. VANISHING SPECIES 334 
 
 25. ORIGIN OF THE DIVERSE FORMS OF ANIMA.L LIFE . . , 342 
 
INTRODUCTION 
 
 METHODS, EQUIPMENT, ETC. 
 
 The Biological Sciences. All living things belong either 
 to the plant or to the animal kingdom. An individual of 
 either group is termed an organism. A study of the ani- 
 mal organisms constitutes the science of zoology, while 
 botany has for its field the investigation of plant life. The 
 science of biology includes both botany and zoology. 
 
 Any animal or plant may be considered from several 
 different standpoints. A general study of structure and of 
 the relations of the various systems and organs is known as 
 anatomy. The location and parts of the heart and courses 
 of the nerves and blood vessels are questions belonging to 
 this science. Physiology has for its province the investiga- 
 tion of the functions of the organs and systems, and there- 
 fore explains the uses of the heart, lungs, and blood vessels. 
 Inquiries relating to the home life, food, enemies, and ex- 
 ternal appearance of animals belong to the domain of 
 Natural History, which also concerns itself with the same 
 phases of plant life. 
 
 Value of Zoological Study. It is proper that both 
 teacher and pupil should keep in mind the advantages to be 
 derived from the study of animal life, that time may not be 
 wasted on insignificant details. In fact it is the duty of 
 every teacher to present only such portions of a science as 
 11 
 
12 INTRODUCTION 
 
 will be of the greatest economic, educational, and ethical 
 value to the learners. 
 
 Economic Zoology has lately proved itself worthy of the 
 consideration of every American citizen. The number of 
 injurious insects in the United States is large and increas- 
 ing. They often destroy one fourth or even a half, and 
 sometimes the entire crop of a whole section. The agri- 
 cultural products of our country amount annually to about 
 $3,000,000,000, while the loss of crops from the attacks of 
 insects is estimated at $100,000,000. In 1874 in the 
 Western states, the Rocky Mountain locust caused over 
 $40,000,000 of damage. The chinch bug (Fig. 116) in 
 Illinois, during the year 1864, destroyed $70,000,000 worth 
 of crops, and in Missouri ten years later was responsi- 
 ble for the loss of nearly $20,000,000 worth of produce. 
 The governor of Texas recently made an offer of $50,000 
 to any one who should discover a remedy for the ravages 
 of the cotton-boll weevil (Fig. 121) . The San Jose scale 
 (Fig. 107) destroys acres of valuable fruit orchards an- 
 nually. A much greater loss to crops would result yearly 
 were it not for the fact that men have learned by the study 
 of zoology how to control some of the insect pests, and also 
 how to secure the greatest benefits from birds and a large 
 class of insects naturally helpful to man. Ignorance con- 
 cerning the food of hawks and owls caused the Pennsyl- 
 vania legislators in 1885 to pass -a law resulting in a loss 
 to the state of $2,000,000. By becoming acquainted with 
 the habits of animals, man is able to have dominion over 
 them, and by wise legislation to make such laws in regard 
 to their destruction or preservation as will be to the best 
 interests of not only the present but future generations. 
 
METHODS 13 
 
 The Educational Value of zoological studies can not 
 be overestimated. They furnish the means of bringing 
 nature and the child into direct contact, so that he may 
 actually acquire some knowledge by his own powers of 
 perception. Froebel says, " We do not feel the meaning 
 of what we say, for our speech is made up of memorized 
 ideas based neither on perception nor on productive effort." 
 
 Animal life properly studied develops not only the facul- 
 ties of acquisition, but likewise the powers of reflection or 
 reasoning and expression. Essay writing and memoriter 
 recitations are too often wearisome, but if the pupil has 
 learned something of vital interest concerning an animal's 
 life history, habits, and struggle for existence, he will find 
 pleasure in relating his discoveries to his classmates, and 
 thereby will experience a splendid training in the use of 
 intelligent English. 
 
 The Ethical Value to be derived from the study of 
 zoology depends largely on how the subject is taught. 
 Much evil is wrought in our land through ignorance. 
 Youth seldom stop to think how much harm is done when 
 they ruthlessly destroy life. The maiming of a single 
 bird may mean death to many little ones. A careful esti- 
 mate shows that only about half as many birds exist to-day 
 as were present in our country a quarter of a century ago. 
 One chief factor causing the decrease has been ignorance 
 on the part of the people who have sanctioned the robbing 
 of nests and killing of birds. Every boy and girl should 
 go forth from school imbued with the idea that the killing 
 of our best friends in the animal world merely to satisfy a 
 savage instinct is a crime. A face to face acquaintance 
 with the creatures of earth should gain many warm ad- 
 
14 INTRODUCTION 
 
 vocates of the Society for the Prevention of Cruelty to 
 Animals. Moreover, to him who understands the meaning 
 of the well-woven nest by the roadside, the glistening eggs 
 on the tender twig, and the thousand other sights and 
 sounds of the lane and park, there is no nook or cranny of 
 creation without a wholesome interest. 
 
 EQUIPMENT 
 
 Plan of Work. It is not important that the pupils 
 should learn many things, but it is important that they 
 should be taught to observe accurately, to reason carefully, 
 and to express their thoughts in clear English. The 
 teacher will be asked many questions about animals, which 
 he can not answer, and therefore he must realize there is no 
 disgrace in saying; " I do not know, but let us together seek 
 the information in the books and in the animals them- 
 selves." Pupils should be encouraged to ask questions, 
 and those which can not be easily answered may be assigned 
 to one or more individuals for study during the next several 
 days. Agassiz's motto, " Study nature, not books/' ought 
 to hang in every schoolroom. This text-book is not to 
 be memorized; it aims merely to furnish to inquiring minds 
 information about animals. 
 
 If the class becomes specially interested in scale insects 
 and plant lice, or birds and insects, or mosquitoes and 
 other flies, it is wise to devote much time to these and 
 give less study to other forms. Many teachers will find it 
 wise to omit certain chapters and some parts of other 
 chapters, to save time. 
 
EQUIPMENT 15 
 
 Each instructor should choose those subjects for which 
 he can most easily secure the material, and if possible 
 study the various forms of life during that season of the 
 year when they are most active. Insects are best studied 
 in the autumn, the birds in early summer, the reptiles and 
 amphibians in early spring, and the lower invertebrates 
 and mammals hi winter. If only one term is devoted to 
 zoology fewer reference books will be required and a smaller 
 number of animals should be considered. 
 
 As in most cases it is impossible to observe out of doors 
 all the stages in the life history of a species, pupils must 
 learn to study carefully the illustrations in the book and 
 also make use of well-preserved specimens. 
 
 Preservation of Material. Nothing else will create 
 so much interest in this branch as the collection and pre- 
 servation of animals to be used not only by the present 
 but also by future classes. Nearly all insects in the adult 
 state may be preserved by merely allowing them to dry in 
 the air five or six days after the legs and wings have been 
 arranged and pinned in the desired positions. 
 
 A pine board to which are tacked two or three sheets of 
 blotting paper makes a good pinning board. If the wings 
 are to be sprsad the insect should be laid on its back, other- 
 wise it may be placed in its natural position. In either 
 case pins should be so stuck as to hold all parts without 
 penetrating the animal. 
 
 Dried material will be destroyed by museum pests unless 
 placed in tight boxes, which can be made by any boy or 
 girl. Secure two panes of glass of equal size. If they 
 measure eight by ten niches, saw from a thin board four 
 strips a half inch wide, and make two of them eight inches 
 
16 INTRODUCTION 
 
 long and the other two nine inches, so that when put to- 
 gether they will form the sides of the box whose top and 
 bottom are the panes of glass. With mucilage or royal 
 
 FIG. 1. Pinning board. Strips of paper hold the wings, a, Cicada; 6, butter- 
 fly ; c, wood-boring beetle ; d, dragon fly ; e, pupa of hawk moth ; /, galley 
 worm. 
 
 glue cement the strips to one pane and let them dry over 
 night, keeping them pressed closely to the glass by the 
 weight of a heavy book. In place of wood, seven or eight 
 strips of thick pasteboard glued one on top of another 
 
EQUIPMENT 
 
 17 
 
 FIG. 2. First step in making an insect cabinet. 
 
 may serve for the sides of the box. At any time later, the 
 insects may by a drop of glue be stuck to the pane form- 
 
 FiG. 3. Cabinet 5 by 7 inches completed. Cost, six cents. 
 
 ing the bottom of the box and then the top pane glued on. 
 A. neat appearance can be given the cabinet by edging it 
 
18 
 
 INTRODUCTION 
 
 with passe-partout picture binding, to be had at any book- 
 store or photographic supply house. If one such cabinet 
 is prepared each year, a valuable natural history collection 
 will soon result. The centipeds and spiders may be 
 mounted in the same manner as insects, but other animals 
 are better preserved in alcohol or formalin. 
 
 A very neat method of mounting small insects is that 
 of gluing the specimens to a piece of glass and placing 
 
 over them a watch crys- 
 tal held in place by a 
 few drops of glue. 
 
 Pure formalin or for- 
 maldehyde may be pur- 
 chased at the drug store 
 for about fifty cents per 
 pint bottle. One part 
 of this mixed with 
 twenty parts of water 
 makes a solution that 
 will preserve any plant 
 or animal. In case the 
 animal is large, such as 
 a snake or rat, one or 
 two long slits should be 
 made in the abdominal 
 wall so that the fluid 
 may reach the internal organs. Wide-mouthed bottles 
 and fruit jars or small stone jars are the best receptacles for 
 these specimens. 
 
 Painless death may be effected in a half hour by placing 
 any animal in a tight jar or box with a bunch of cotton or 
 
 FIG. 4. Watch-crystal mount. 
 
EQUIPMENT 19 
 
 cloth on which have been placed thirty or forty drops of 
 chloroform for every hundred cubic inches of space. A 
 convenient killing jar for insects is made by having a drug- 
 gist place in a wide-mouthed fruit jar five cents' worth of 
 potassium cyanide in small pieces, which must be covered 
 with a thick solution of plaster of Paris in water. In 
 order that the plaster may dry the jar should be left open 
 a day or two and then kept closed except when putting in 
 or removing animals. Potassium cyanide is a deadly 
 poison. A wide-mouthed cyanide bottle is convenient 
 for pupils to use in the field. 
 
 Keeping Live Animals. With but slight trouble and 
 great profit many animals may be kept alive in the school 
 room or laboratory. Snakes, turtles, and lizards live com- 
 fortably in a covered box containing dry earth and a soup 
 plate with water. A turtle will eat fresh beef, but the 
 lizard and snake need a weekly meal of beetles, flies, or 
 earthworms. Tadpoles, newts, fish, water fleas, various 
 insect larvae, a few worms, hydra, and many protozoans 
 flourish in aquaria consisting of glass jars or dishes filled 
 with water and containing a few water plants. The water 
 need not be changed if the bulk of the plants is about one 
 fourth that of the animals. A few bits of fresh beef should 
 be given the vertebrates once a week. The aquarium 
 needs good light but not necessarily direct sunshine in 
 order that the plants may flourish and furnish oxygen for 
 the animals. Gallon battery jars to be had of the Whitall, 
 Tatum Co., of New York, serve excellent aquarium pur- 
 poses and cost but fifteen cents each. 
 
 If animals which one can not secure in his own locality 
 are desired, they may be obtained of the following dealers: 
 
20 
 
 INTRODUCTION 
 
 American Entomological Company, 1040 DeKalb Ave., 
 
 Brooklyn, N. Y. All kinds of insects. Catalogue 
 
 on application. 
 Brimley Bros., Raleigh, N. C. Living and preserved 
 
 animals. 
 Biological Laboratory, Cold Spring Harbor, L. I., N. Y. 
 
 Marine animals. Catalogue on application. 
 Tufts College Laboratory, South Harpswell, Me. 
 Hopkins Seaside Laboratory, Stanford University, Cal. 
 
 FlG. 5. Dissecting instruments. 
 
 St. Louis Biological Laboratory, St. Louis, Mo. Numer- 
 ous kinds of animals and microscopical slides showing 
 structure of animals. Catalogue on application. 
 
 The Laboratory. This should be a well-lighted room 
 
EQUIPMENT 21 
 
 containing a number of tables with drawers for the use of 
 the pupils, and several shelves or cases for holding pre- 
 served material. If such a workroom is not available 
 two or three tables placed in the schoolroom will be found 
 of great use. For those who wish to do much in the line 
 of dissection a few thirty-five cent scalpels, or dissecting 
 knives, forceps, needles, scissors, and trays both of tin 
 and wood are necessary. The bottoms of the tin trays 
 should be covered with a quarter-inch layer of melted 
 paraffine to which the small animals are to be pinned while 
 being dissected under water. 
 
 At least one or two compound microscopes are neces- 
 sary. A satisfactory instrument can be purchased for 
 about $30. A few dissecting microscopes costing about 
 $2.50 each are of service in the study of many forms. 
 
 A half gross of glass object slides and a half ounce of num- 
 ber two cover glasses are required for the examination of 
 microscopic objects. A bottle of chloroform and a quarter 
 of an ounce of chloretone dissolved in a quart of water 
 should be ready for use as described in the special lessons. 
 
 Books. The pupils in addition to their text-books 
 will take an interest in consulting the following references 
 if they are accessible: 
 
 APGAR, A. C. : Birds of the United States. American Book Com- 
 pany. $2.00. Will help one to identify the birds in the hand 
 or in the field. 
 
 *BERGEN, J. Y. and F. D: A primer of Darwinism and Organic 
 Evolution. Lee & Shepard. Boston. $1.25. Explains how 
 species have originated. 
 
 *BLANCHAN, NELTJE: Bird Neighbors. Doubleday, Page & Com- 
 pany. New York. $2.00. Contains colored plates and enables 
 one to identify one hundred and fifty birds in the field. 
 
22 INTRODUCTION 
 
 BUBNET, MARGARETTA: Zoology for High Schools and Academies 
 American Book Company. 
 
 *CHAPMAN, F. M.: Bird-Life. D. Appleton & Company. New 
 York. $1.75. A good book for beginners. 
 
 DAVENPORT, C. B. and G. C: Introduction to Zoology. Mac- 
 millan & Company. New York. $1.10. 
 
 DAVISON, ALVIN: Mammalian Anatomy. P. Blakiston's Son & 
 Company. Philadelphia. $1.50. Treats of the preparation 
 and preservation of mammals for dissection and their anatomy. 
 Valuable for a teacher of physiology. 
 
 DODGE, C. W.: General Zoology. American Book Company. 
 New York. 
 
 HORNADAY, W. T. : American Natural History. Charles Scribner's 
 Sons. New York. $3.50. Treats of vertebrates only. 
 
 *!NGERSOLL, E. : Nature's Calendar. Harper and Brothers. New 
 York. $1.50. Contains practical suggestions for outdoor obser- 
 vations. 
 
 JORDAN, D. S. : Manual of Vertebrate Annuals of Northern United 
 States. McClurg & Company. Chicago. $2.50. Enables one 
 to identify any vertebrate. 
 
 KJNGSLEY, J. S.: Elements of Comparative Zoology. Henry Holt 
 & Company. New York. $1.20. 
 
 LECONTE, J.: Evolution and its Relation to Religious Thought. 
 D. Appleton & Company. New York. $1.50. 
 
 *LUCAS, F. A. : Animals of the Past. McClure, Phillips & Com- 
 pany. New York. $2.00. A popular account of fossil remains. 
 
 MARSHALL, C. M. and HURST, C. H-: Practical Zoology. G. P. 
 Putnam. New York. $3.50. Directions are given for dissect- 
 ing rabbit, pigeon, dogfish, and other forms. 
 
 *NEEDHAM, J. G. : Outdoor Studies. American Book Company. 
 New York. $ .40. 
 
 PARKER, T. J. and HASWELL: Text-book of Zoology. Macmillan 
 & Company. New York. $9.00. A thorough and clear treat- 
 ise. 
 
 *SANDERSON, E. D. : Insects Injurious to Staple Crops. Wiley & 
 Company. New York. $1.50. 
 
EQUIPMENT 23 
 
 *STOKES, A. C. : Aquatic Microscopy for Beginners. E. F. Bige- 
 
 low. Portland, Connecticut. $1.25. Useful in identifying 
 
 small water animals. 
 *WEED, C. M. and DEARBORN, N. : Birds in their Relation to Man. 
 
 J. P. Lippincott & Company. Philadelphia. A valuable book. 
 
 The books in the above list marked with an asterisk will be found 
 most valuable for elementary work. 
 
 Every school will find interesting and valuable information in 
 the Yearbooks of the Department of Agriculture which may be had 
 free of charge by applying to the United States senator or repre- 
 sentative of the district in which the school is located. Back 
 numbers may be had at second-hand book stores for about twenty 
 cents each. 
 
 The following useful bulletins and circulars will be sent free upon 
 application to the Secretary of Agriculture, Washington, D. C. 
 
 Some Insects Injurious to Stored Grain, pp. 24, figs. 18. 
 
 Insects Affecting the Cotton Plant, pp. 32, figs. 18. 
 
 Some Common Birds in Their Relation to Agriculture, pp. 48. 
 
 Bee Keeping, pp. 32, figs. 19. 
 
 The Principal Insect Enemies of the Grape, pp. 23, figs. 12. 
 
 The Peach Twig-Borer, pp. 16, figs. 5. 
 
 Three Insect Enemies of Shade Trees, pp. 30, figs. 11. 
 
 The Principal Insects Affecting the Tobacco Plant, pp. 32, figs. 
 25. 
 
 Important Insecticides, pp. 42, figs. 6. 
 
 The Principal Insect Enemies of Growing Wheat, pp. 40, figs. 25. 
 
 How Insects Affect Health in Rural Districts, pp. 20, figs. 16. 
 
 Silk Worm Culture, pp. 32, figs. 15. 
 
 The Control of the Coddling Moth, pp. 24, figs. 4. 
 
 Scale Insects and Mites on Citrus Trees, pp. 43, figs. 34. 
 
 Insects Injurious in Cranberry Culture, pp. 32, figs. 12. 
 
 Information concerning the Cotton Boll Weevil, pp. 31, figs. 8. 
 
 The Cotton Boll Worm, pp. 24, figs. 7. 
 
 Usefulness of the Toad, pp. 16. 
 
 Reindeer and Caribou, pp. 14, pis. 7. 
 
 Bird Day in the Schools, pp. 4. 
 
24 INTRODUCTION 
 
 The Hop Plant Louse, pp. 7, figs. 6. 
 
 The Army Worm, pp. 5, figs. 3. 
 
 The Carpet Beetle, or Buffalo Moth, pp. 4, fig. 1. 
 
 Canker Worms, pp. 4, figs. 4. 
 
 Mosquitoes and Fleas, pp. 6. 
 
 The Strawberry Weevil, pp. 7, figs. 4. 
 
 The Ox Warble, pp. 10, figs. 10. 
 
 The Pear Slug, pp. 7, figs. 4. 
 
 The Fruit-tree Bark-Beetle, pp. 8, figs. 4. 
 
 The Striped Cucumber Beetle, pp. 7, figs. 2. 
 
 The Larger Apple Tree Borers, pp. 12, figs. 3. 
 
 House Ants, pp. 4, figs. 3. 
 
 House Flies, pp. 8, figs. 8. 
 
 The True Clothes Moth, pp. 8, figs. 3. 
 
 The Common Squash Bug, pp. 5, figs. 3. 
 
 How to Distinguish the Different Mosquitoes of America, pp. 8. 
 
 The Bed-bug, pp. 8, figs. 3. 
 
 The House Centipede, pp. 4, figs. 2. 
 
 The Silver Fish, pp. 4, figs. 2. 
 
 Cockroaches, pp. 15, figs. 5. 
 
 The Peach Tree Borer, pp. 6, fig. 1. 
 
 Four Common Birds of the Farm and Garden, pp. 14, figs. 4. 
 
 The Meadow Lark and Baltimore Oriole, pp. 12, figs. 2. 
 
 Asparagus Beetles, pp. 12, figs. 6. 
 
 Insects Injurious to Beans and Peas, pp. 28, figs. 17. 
 
 The Food of Nestling Birds, pp. 26, figs. 14. 
 
 Smyrna Fig Culture in the United States, pp. 28, figs. 15. 
 
 How Birds Affect the Orchard, pp. 14, figs. 5. 
 
 Insects as Carriers and Spreaders of Disease, pp. 16, figs. 15. 
 
 The San Jose Scale: Home and Natural Enemies, pp. 20, figs. 9. 
 
 Insects Injurious to Hardwood Forests, pp. 16, figs. 17. 
 
 Audubon Societies in Relation to the Farmer, pp. 14, figs. 4. 
 
 Some New Facts about the Migration of Birds, pp. 16, figs. 2. 
 
 A monthly list of publications by the United States Government 
 may be had free of charge by sending the request to the Secretary 
 of Agriculture, Washington, D. 0. 
 
CLASSIFICATION 
 
 25 
 
 CLASSIFICATION 
 
 For the sake of convenience in discussing the character- 
 istics of animals the entire kingdom is divided into sub- 
 kingdoms, classes, orders, families, and species, as given in 
 the following outline. It is not intended that this incom- 
 plete table of classification should be memorized, but 
 rather that the pupils should become familiar with it as 
 indicated in the practical questions by constant reference 
 to it throughout the term. 
 
 SUBKINGDOM I. PnoTOz5'A (first animals) : Single-celled 
 aquatic animals of microscopic size. Ameba 
 and Paramcecium (Figs. 211, 209). 
 
 SUBKINGDOM II. PORIF'ERA (pore bearers): Sponges. 
 
 SUBKINGDOM III. COSLENTERA'TA (hollow within): Aquatic 
 mostly marine animals having but one inter- 
 nal cavity. Jellyfish, coral builders, and 
 hydroids (Figs. 203, 199). 
 
 SUBKINGDOM IV. PLA"TYHELMIN'THES (flatworms) : Worms with 
 flattened bodies and no cavity surrounding 
 the alimentary canal. Tapeworms and 
 liver fluke (Fig. 184). 
 
 SUBKINGDOM V. NEMATHELMIN'THES (thread worms): Round 
 worms with no external evidence of seg- 
 ments. Horsehair worm and vinegar eel 
 (Fig. 183). 
 
 SUBKINGDOM VI. TROCHELMIN'THES (wheel worms): Minute 
 aquatic worms with cilia about the mouth. 
 Rotifer. 
 
 SUBKINGDOM VII. MOLLUSCOI'DA (like a mollusk) : Aquatic 
 worms usually living in colonies. Sea mats. 
 
 SUBKINGDOM VIII. ECHINODER'MATA (spiny skinned) : Marine 
 radiate forms often covered with spines. 
 Starfish and sea urchin (Figs. 187, 190). 
 
26 INTRODUCTION 
 
 SUBKINGDOM IX. ANNULA'TA (with rings): Worms with seg- 
 ments apparent externally. Earth worm 
 and leech (Figs. 178, 179). 
 SUBKINGDOM X. MOLLUS'CA (soft): Soft-bodied forms usually 
 
 with a shell. Oysters, snails, slug, squid. 
 SUBKINGDOM XL ARTHRO'PODA (jointed feet) : Segmented forms 
 
 with jointed legs. Crabs, beetles, wasps. 
 
 Class 1. Crusta'cea (crust) : Arthropoda with head and thorax 
 fused and usually a hard outer skeleton. Crayfish (Fig. 155), 
 lobster, pill bug (Fig. 164). 
 
 Class 2. Myria'poda (thousand-footed) : Forms with air tubes 
 throughout the body and numerous legs. Centipeds (Fig. 
 152), millepeds (Fig. 153). 
 Class 3. Arach'nida (spider) : Forms with usually four pairs of 
 
 legs and no antennae. Spiders, scorpions (Figs. 144-151). 
 Class 4. Insec'ta (cut-in) : Forms with body showing three dis- 
 tinct parts called head, thorax, and abdomen ; and breathing 
 by means of tubes ramifying among the tissues and opening 
 on the lateral aspect of the body (Figs. 9, 10). 
 Order a. Ephemer'ida (lasting one day) : Forms with two unequal 
 pairs of wings, no mouth parts, and two or three filaments 
 projecting from the end of the abdomen. May fly (Fig. 139). 
 Order b. Odona'ta (tooth) : Forms with four nearly equal mem- 
 branous wings. Dragon flies, damsel flies (Figs. 140, 141). 
 Order c. Orthop'tera (straight-winged) : Forms usually with 
 four wings, the hinder ones being thin and overlapped by the 
 thick fore wings when at rest. Grasshoppers, crickets, cock- 
 roaches (Figs. 11, 13). 
 
 Order d. Hemip'tera (half-winged) : Forms which take food by 
 sucking only. Bedbug, cicada, plant lice, scale insects 
 (Figs. 98, 107). 
 
 Order e. Neurop'tera (nerve-winged) : Forms with two pairs 
 of membranous net-veined wings. Dobson or hellgramite 
 (Fig. 138). 
 
 Order f. Lepidop'tera (scale-winged) : Forms with two pairs 
 of wings covered with overlapping scales. Butterflies, 
 moths, millers. 
 
CLASSIFICATION 27 
 
 Order g. Dip'tera (two-winged) : Forms with only one pair of 
 wings and behind them a pair of short-knobbed processes, 
 the halteres. Flies and mosquitoes. 
 
 Order h. Coleop'tera (shield-winged) : Forms with a pair of horny 
 wing covers and a single pair of membranous wings. Beetles. 
 Order i. Hymenop'tera (membrane-winged) : Forms with two 
 pairs of membranous wings, mouth parts for both biting and 
 sucking, and the female usually with a sting, pierce, or saw. 
 Ants, bees, wasps (Figs. 32, 36). 
 
 SUBKINGDOM XII. PHOTO CHORD A'TA (first cord) : Marine animals 
 forming a connecting link between the ver- 
 tebrates and invertebrates. Sea-squirts, 
 lancelet. 
 
 SUBKINGDOM XIII. VERTEBRA'TA (turning) : Forms with a skele- 
 tal axis and a dorsal nerve cord whose an- 
 terior end is dilated into a brain. 
 Class 1. Pisces (fish) : Aquatic cold-blooded forms with gills and 
 
 usually paired fins, but not legs. 
 
 Class 2. Amphib'ia (both lives): Cold-blooded forms without 
 scales, usually with two pairs of legs, and breathing by gills in 
 early life. Frogs, salamanders, toads (Figs. 230, 231). 
 Class 3. Reptll'ia (to creep): Cold-blooded forms with scales 
 
 and lungs. Snakes, lizards, turtles. 
 
 Class 4. A'ves (birds) : Warm-blooded vertebrates with feathers. 
 Class 5. Mamma'lia (with breasts) : Hairy vertebrates suckling 
 their young. Dog, monkeys, man. 
 Order a. Monotre'mata (single opening) : Egg-laying mammals. 
 
 Duck mole, spiny ant-eater (Figs. 297, 300). 
 Order b. Marsupia'lia (pouch) : Mammals whose young at 
 birth are very small and immature and are therefore placed 
 in an abdominal pouch to be nourished several weeks. 
 Opossums, kangaroos (Figs. 299, 298). 
 Order c. Insectlv'ora (insect eaters) : Mammals living largely on 
 
 insects. Shrews, moles (Fig. 311). 
 
 Order d. Edenta'ta (without teeth) : Forms in which the teeth 
 are often wanting and if present there is no enamel. Sloths, 
 ant-eaters. 
 
28 INTRODUCTION 
 
 Order e. Chirtip'tera (hand- winged) : Forms adapted for flight. 
 
 Bats, flying foxes (Fig. 310). 
 Order f. Roden'tia (gnawing): Mammals having usually two 
 
 elongated chisel-like incisors in each jaw. Rabbits, squirrels, 
 
 mice, rats (Fig. 309). 
 Order g. Ceta'cea (whale): Marine mammals with fishlike 
 
 body and no hind limbs. Whales, porpoises, dolphins. 
 Order h. Siren'ia (siren) : Aquatic forms with no hind limbs. 
 
 Sea cow. 
 Order i. Ungula'ta (bearing hoofs): Mammals which have 
 
 hoofed feet. Horse, cow, pig. 
 Order j. Carnlv'ora (flesh-eating): Mammals living on flesh 
 
 and with strong canine teeth and claws. Dogs, cats, wolves, 
 
 foxes. 
 Order k. Primates (first) : Mammals with thumb opposable to 
 
 the other digits. Lemurs, monkeys, man. 
 
 A glance at the above outline shows that the entire ani- 
 mal kingdom, consisting of a half million species, is divided 
 into thirteen subkingdoms sometimes called phyla or 
 branches. Each of these is composed of several classes, 
 but in most cases the names of the classes are not given. 
 The divisions of the classes are designated orders which 
 in turn are divided into families. A family is composed 
 usually of several genera, and each genus is still further 
 divided into species. 
 
 Linnaeus of Sweden invented the system of binomial 
 nomenclature, in accordance with which the name of every 
 plant or animal is composed of two parts, the generic 
 which is a noun, and the specific, which is an adjective. 
 Thus, the house cat is called Fells domestica; the lion 
 Felis leo ; the dog, Canis familiaris; the wolf, Canis latrans; 
 the red squirrel, Sciurus hudsonicus ; the gray squirrel, 
 Sciurus carolinensis. Animals of the same genus but of 
 
CLASSIFICATION 29 
 
 different species resemble each other much closer than do 
 animals of two different families, and still fewer characters 
 are common to animals belonging to different orders. 
 Thus, the horse, Equus caba'lus, and the ass, Equus asi- 
 nuSj differ chiefly as to the tail and ears only. Both belong 
 to the order Ungulata and family Equidce. The cow, Bos 
 taurus, of the same order but of the family Bovidce, differs 
 much from the horse and ass in possessing shorter legs with 
 two toes, a pair of horns, and no upper incisor, or canine 
 teeth. The black bear, Ursus americanus, presents great 
 contrast in structure to the above animals and is therefore 
 placed in another order, Carnivora. It feeds on flesh, has 
 teeth adapted to cutting instead of grinding, and claws in 
 place of hoofs. 
 
 Since a fish resembles the above animals in having a 
 back bone, a brain, and nerve cord on the dorsal side it is 
 placed in the same subkingdom, Vertebrata, but must be 
 assigned to another class, Pisces, on account of the absence 
 of hair, limbs, lungs, and other features common to the 
 mammals. 
 
PART I 
 
 ARTHROPODA: SEGMENTED FORMS WITH 
 JOINTED LEGS 
 
 1. ORTHOPTERA 
 
 THE majority of the species of animals belong to the 
 branch Arthropoda. A feature distinguishing this group 
 from all other invertebrates is the presence of jointed legs. 
 These, however, may be absent in a few forms leading a 
 parasitic life (Fig. 150) . Of the four classes of Arthropoda, 
 the insects, numbering over three hundred thousand 
 
 FIG. 6. A, Long-horned grasshopper; B, Locust; a, antennae; o, ovipositor. 
 
 species, are the most important because among them are 
 found man's greatest enemies as well as valuable helpers. 
 
 Locusts 
 
 The locusts, commonly called grasshoppers, include about 
 three hundred different species, but only three or four kinds 
 are easily found in any one locality. Only the short-horned 
 30 
 
OKTHOPTEltA 
 
 31 
 
 grasshoppers (Acndfidcs) , which means those having an- 
 tenna half the length of the body, or less, are true locusts. 
 Those with antenna nearly as long as the body, or longer, 
 are the true grasshoppers (Locustidce) . Such is the katy- 
 did (Microcentrwn retinervis), which is more than an inch 
 long and has wings so veined and colored as to resemble a 
 green leaf. 
 
 Habits. In most cases the eggs of the locust, number- 
 ing from ten to a hundred and having somewhat the form 
 of grains of wheat, are 
 laid during July or Au- 
 gust in the soil. They 
 are held together in ir- 
 regular masses by a ce- 
 ment. The majority of 
 the species pass the 
 winter in the egg state, 
 but the large American 
 locust, or bird grass- 
 hopper of our southern states, hibernates as an adult. The 
 young locusts, called nymphs, emerge from the eggs hidden 
 a half inch or more in the soil, during early summer. 
 Forms from a fourth of an inch to a half inch long and 
 wingless may be found in abundance in the grassy fields 
 during May and June. If some of these are caught and 
 fed with grass daily for a week or two the observer may 
 have the rare pleasure of seeing the insect molt, i.e., shed 
 its skin. Most insects molt during their growth period 
 from three to six times. 
 
 After the locust's first molt the wing pads appear as 
 tiny projections, and after the third molt they are quite 
 
 FIG. 7. Locust about two weeks old. Pho- 
 tograph twice natural size. 
 
32 
 
 ARTHROPODA 
 
 conspicuous, but they do not serve for flight till after the 
 last molt, when the insect is said to have completed its 
 transformation from the nymph to the adult state. In 
 most regions the mature insects may be found in grassy 
 fields from July till frost appears. 
 
 External Features. The food of the locusts is almost 
 any kind of green herbs, which they bite off with a pair of 
 hard lateral moving mandibles. 
 An examination of the mouth 
 region shows an upper lip or 
 labrum covering the front side 
 of the mandibles, which are 
 easily recognized by their hard- 
 ness and serrated inner mar- 
 gins. Behind these is a pair 
 of maxillce divided into three 
 lobes, the outer and longer of 
 which is the feeler, or palpus. 
 Next in order is the lower lip, or 
 labium, apparently composed of 
 two lateral halves, each bearing 
 a palpus. 
 
 'JLS n 
 
 n 
 
 , r ~. r Most biting insects 
 
 FIG. 8. Mouth parts of a locust. . 
 
 , antenna; I, labrum turned for- present mouth parts similar to 
 
 these. The mosquitoes and 
 
 \vard to expose the mandibles, m; 
 
 n, maxilla reflected ; 6, palpi of 
 
 the maxilla ; t, labium. Twice some flies and bugS have 
 
 natural size. Drawing by Reese. . . . . 
 
 ing but not biting mouth parts. 
 
 The locust's body is divided into three parts: the head, 
 bearing a pair of many-jointed antennae; the thorax, sup- 
 porting three pairs of legs and two pairs of wings, the an- 
 terior of which are parch men tlike and serve to cover the 
 posterior which are membranous and folded longitudinally 
 
ORTHOPTERA 
 
 38 
 
 like a fan when the insect is at rest; and the abdomen, which 
 in the female terminates in two pairs of sharp-hooked 
 spines forming the ovipositor or egg-depositing apparatus. 
 The thorax and abdomen are composed of ringlike portions, 
 called somites, of which the three in the thorax are named 
 prothorax, mesothorax, and metathorax. The part of the 
 somite on top is the tergum, that underneath is the 
 sternum, and on the sides are the pleura. Eleven somites 
 
 FIG. 9. Locust with the left wing w cut off near the base, a, antennae ; d, ear ; 
 e, compound eye ; /, femur ; J, labrum ; m, maxilla ; n, front leg of right side ; 
 o, mandible ; p t palpus of right maxilla ; r, tarsus ; s, segments of the abdo- 
 men ; t t tibia ; tr, trochanter ; photograph, natural size. 
 
 are present in the abdomen, and the dorsal (upper) and 
 ventral (under) part of each is composed of a single plate 
 named the tergite and sternite, respectively. The sternites 
 of the last three somites are wanting in the female. 
 
 Each leg is composed of a short proximal segment, the 
 trochanter; a second segment, stout and long, known as the 
 femur; a third segment, long and slender, called tibia, and 
 a terminal portion made of several pieces forming the 
 
34 
 
 ARTHROPODA 
 
 tarsus. Between the two claws at the end of the tarsus 
 is a little pad, the pulvillus, which enables the animal to 
 walk on smooth surfaces. Directly behind the bases of 
 the antennae are the two large compound eyes composed 
 of hundreds of cones whose ends, called facets, may be seen 
 on the surface with a good hand lens or low power of the 
 compound microscope. Three ocelli, or simple eyes, well 
 seen with a hand lens, are also present. As hi most insects, 
 
 the median one is between 
 
 the antennae and the lateral 
 ones just in front of the 
 compound eyes. The ear 
 is a circular opening covered 
 by membrane on the side 
 of the first abdominal seg- 
 ment. On the lateral aspect 
 of each of the eight anterior 
 segments of the abdomen 
 and the two posterior seg- 
 ments of the thorax is a 
 minute opening barely vis- 
 
 Photograph of a spiracle with ible to the naked eye. It 
 is the spiracle, which admits 
 air to a tube branching 
 profusely among the tissues for the purpose of supplying 
 all parts with oxygen and carrying away the carbon 
 dioxide formed in every region of an animal's body. 
 These ramifying tubes, called trachece, are common to all 
 insects and a few other Arthropoda. 
 
 Destruction of Crops. Locusts have always been a 
 great pest to man, as may be inferred from the destructive 
 
 FIG. 10. 
 
 Its tracheae removed from an insect. 
 , spiracle. Three times natural size. 
 
ORTHOPTERA 35 
 
 powers of the insects frequently mentioned in the Scrip- 
 tures. Williamson's History of Maine says: " In 1749 
 and 1754 they were very numerous; no vegetables escaped 
 these greedy troops; they even devoured the potato tops; 
 and in 1743 and 1756 they covered the whole country and 
 threatened to devour every green thing. Indeed, so great 
 was the alarm they occasioned among the people, that 
 days of fasting and prayer were appointed." In 1838 
 the common red-legged locust (Melanoplus femur-rubrum) 
 was so abundant in parts of Maryland that the negroes 
 were employed to drive them from the gardens with rods. 
 The most injurious species occur: ing in this country is 
 the Rocky Mountain locust (Melanoplus spretus) or mi- 
 gratory locust. From 1874 to 1876 they damaged west- 
 ern agriculture, especially in Kansas, Colorado, Nebraska, 
 and Missouri, to the extent of over two hundred million 
 dollars. The government appointed a special committee 
 to devise a remedy to exterminate or check the pest, and 
 numerous plans for destroying the eggs, young, and adults 
 were brought forward. In Minnesota one farmer col- 
 lected during the latter part of June about eight hundred 
 bushels, by dragging with horses across the grain fields 
 after dark a large box with the front side removed so as to 
 allow the insects to tumble in. Another farmer in the 
 same manner captured four hundred bushels. Some 
 counties paid a reward for locusts collected and killed. 
 In 1875 Nicollet County, Minnesota, paid a dollar per 
 bushel for 25,053 bushels of locusts. Fortunately the 
 insects appear in large numbers only at intervals of from 
 five to twenty or more years, according to the condition of 
 the weather and the presence of enemies. The Rocky 
 
36 
 
 ARTHROPODA 
 
 Mountain locust is always present in greater or less num- 
 bers in Montana and parts of Dakota, Wyoming, Colorado, 
 Utah, Idaho, and Oregon. On certain occasions swarms 
 of many millions migrate to the adjacent states, being 
 driven by the wind as they hold 
 the wings expanded, but they 
 have never been found east of the 
 Mississippi River. The Carolina 
 locust (Dissosteira Carolina), the 
 large gray species frequenting the 
 roadside everywhere in late sum- 
 mer, and recognized by its yellow- 
 bordered hind wings, seldom be- 
 comes so numerous as to cause 
 much damage. 
 
 The Black Cricket 
 
 The short-winged black cricket 
 (Gryllus abbreviatus) is a common 
 autumn insect in every pasture 
 and may frequently be found un- 
 der boards and stones as late as 
 December. The female is distin- 
 guished from the male by the long 
 ovipositor projecting from the end 
 Natural of the abdomen, through which eggs 
 pass into holes made in the ground. 
 Here they remain from fall until spring, when the little 
 crickets emerge in the nymph stage without wings. The 
 crickets are celebrated for their high-pitched chirping, 
 produced by the male only, by elevating over the back 
 
 ius abbreviates). 
 
ORTHOPTEBA 
 
 87 
 
 and rubbing together the two wing covers or outer wings 
 on the bases of which are roughened portions. The rate 
 of chirping is according to the temperature of the air. 
 
 , chirps per minute 40 
 The formula, temperature = 50 H r 
 
 will enable any one to know how high the mercury stands. 
 The sounds made 
 by the male locusts 
 are produced in 
 some species by rub- 
 bing the hind legs 
 against the outer 
 wings and in others 
 by rubbing together 
 the upper surface 
 of the front edge of 
 either hind wing and 
 the under surface 
 of a wing cover. All 
 the high shrill notes 
 of the upland heard 
 on dull days and in 
 the evening are pro- 
 duced by the crick- 
 ets, grasshoppers, or 
 locusts on whose legs 
 or wings the rough 
 
 Surfaces OCCUr. The FIG. 12. Walking stick (JXapheromera femorata). 
 cricketfeedsOngraSS, Photograph, natural size. 
 
 clover, or almost any other kind of vegetation. There are 
 numerous species of the cricket family (GrylUdce) . 
 
38 
 
 ARTHROPODA 
 
 Walking Sticks. The walking sticks (Phasmidce) are 
 so called because of their resemblance to a twig. Our 
 common one (Diapheromera femorata) occasionally be- 
 comes so numerous as to 
 strip all the foliage from 
 acres of forests. 
 
 Cockroaches. Of the 
 four common species of 
 roaches (Blattidce) two are 
 household pests imported 
 from Europe. The large 
 black roach (Periplaneta 
 orientalis) frequents sugar 
 refineries, slaughter- 
 houses, and bake-shops. 
 The Croton bug (Ectobia 
 germanicd) is common in 
 kitchens. Roaches are 
 omnivorous. They feed 
 clothing, bookbind- 
 breadstuffs, and 
 living insects, such as 
 bedbugs. Ships some- 
 times become so badly 
 infested with roaches that 
 the sailors wear gloves 
 while sleeping to prevent 
 
 on 
 
 FIG. 13. Large black roach. Photograph 
 nearly twice natural size. 
 
 the insects from gnawing 
 their fingers. The eggs are inclosed in bean-shaped packets 
 and may be seen hanging fast to the abdomen of the 
 female or found in protected crevices. 
 
DIPTERA 
 
 39 
 
 2. DIPTERA 
 
 This order includes all the true flies. They are the only 
 insects except the male scale insects and a few May flies 
 which have but two wings. About forty thousand species 
 are known. Their study is of great importance because 
 among them are some of our most deadly enemies, while 
 others are our best friends. 
 
 Mosquitoes 
 
 The mosquitoes have a typical life history, and as they 
 are in all parts of the world even as far north as Lapland 
 and Greenland, the pupils will find no difficulty in secur- 
 ing specimens. Their habits may be 
 studied from April to November by 
 securing the eggs or larvae and plac- 
 ing them in a jar of water with some 
 algae (frog spittle, etc.) . These may 
 be found in quiet pools of water not 
 inhabited by fish. A rain barrel or a 
 pail of water that has remained out of 
 doors a few nights is apt to contain 
 them. 
 
 Life History. The eggs of the com- 
 mon species, Culex, are laid so that the 
 two or three hundred stand on end 
 and stick close together, forming a 
 grayish floating mass nearly a quarter 
 of an inch long. They are deposited early in the morn- 
 ing and often hatch within a day into minute wrig- 
 gling larvce which continue to grow from seven to 
 
 FIG. 14. Eggs of mos- 
 quitoes. A, Culex; B, 
 Anopheles photograph- 
 ed on the water, natu- 
 ral size. 
 
40 ARTHROPODA 
 
 fourteen days and attain a length of a half inch or more. 
 If the eggs are laid in late fall they may not hatch until 
 the next spring. The larva rises to the top of the water 
 at intervals to breathe through a tube projecting from the 
 tail end. This tube extends throughout the body and 
 thereby supplies the tissues with oxygen. 
 
 After three molts the pupa stage is assumed and lasts 
 from two to five days, depending upon the temperature, 
 
 FlG. 15. Three pupae and two larvae of mosquitoes at the surface of the water 
 breathing. Photograph from life, twice natural size. 
 
 during which air is admitted to the body by two earlike 
 organs on the thorax. In the next transformation the 
 adult mosquito emerges from a slit in the back of the pupal 
 skin and is ready in a few minutes to fly. 
 
 Food. In its method of taking food the mosquito 
 differs from the locust, as it has no biting apparatus but a 
 piercing and sucking organ forming the proboscis. The 
 labrum (upper lip) and Idbium (lower lip) form a tube inclos- 
 ing the pair of hairlike mandibles and maxillce in addition 
 to a tubular stylet, the hypopharynx, an outgrowth from 
 the floor of the mouth. The hypopharynx lies against 
 
DIPTERA 
 
 the labrum so as to form 
 a canal through which 
 the food passes (Fig. 18) . 
 These several partsmay be 
 seen under the microscope 
 by placing the head of a 
 female in a drop of water 
 on a glass slide and press- 
 ing lightly on the cover 
 glass laid over it. The 
 favorite food of the female 
 is blood of any of the 
 vertebrates. The male 
 never bites and may be 
 distinguished from the 
 female by the antennae 
 which are much more 
 richly feathered. The 
 two chief genera of the 
 four hundred species of 
 mosquitoes are Culex and 
 Anopheles. In the female 
 of Culex, the palpi are 
 not more than a fourth 
 as long as the proboscis, 
 while in Anopheles, the 
 proboscis and palpi are 
 almost equal. The palpi 
 are quite long in the 
 males of both genera. 
 When at rest, the pro- 
 
42 
 
 ARTHKOPODA 
 
 boscis, head, thorax, 
 and abdomen of Ano- 
 pheles are all in a 
 straight line, and the 
 body is held oblique 
 to the surface to which 
 the insect adheres, 
 apparently trying to 
 stand on its head. 
 Members of the genus 
 Culex have a bend at 
 the juncture of the 
 abdomen and thorax 
 and hold the body par- 
 allel with the surface 
 to which they cling. 
 Agents of Disease. About the year 1899 it was clearly 
 shown that the several species of Anopheles are the agents 
 
 FIG. 17. Photograph of Anopheles, the agent 
 transmitting malaria. The antenna? are curved 
 and the upper two of the three straight projec- 
 tions from the head are the palpi. Enlarged 
 three diameters. 
 
 FIG. 18. Diagrammatic vertical section of the head and proboscis of a mosquito. 
 I, labium bent as when the other parts pierce the skin ; p. pumping organ ; o, 
 hypopharynx through which is a channel for the exit of the secretions of the 
 poison and salivary glands pn and s ; d, exit for poison and saliva ; m, maxilla ; 
 ma, mandible ; la, labrurn below which is the channel conducting the food from 
 the inlet at n ; st, stomach. Drawing by Reese. 
 
 in transmitting the malaria from man to man. When the 
 mosquito feeds on the blood of a malaria patient thou- 
 
DIPTEKA 
 
 48 
 
 sands of the germs, 
 Hcemameba terti- 
 ana, are taken into 
 its stomach, from 
 which they migrate 
 to the salivary 
 glands (Fig. 18), and 
 thence are forced 
 with the saliva into 
 persons bitten later. 
 The saliva is ejected 
 by the mosquito 
 to break up the red 
 blood cells which 
 are too large to pass 
 through its pro- 
 boscis. The itch- 
 ing and painful 
 effect of the bite are 
 due to the poison 
 injected along with 
 the saliva. 
 
 Lately it has been shown that yellow fever is trans- 
 mitted by mosquitoes and in no other way. The only 
 offender is Stegomyia fasciata. It is probable that these 
 insects are responsible for some other diseases affecting 
 man. 
 
 Destruction of Mosquitoes. On account of the fact that 
 the mosquitoes are responsible for more sickness and 
 death annually than all the wars of the world, efforts are 
 being made to exterminate them by draining the stagnant 
 
 FIG. 19. Photograph of heads of mosquitoes. A, 
 male ; -B, female ; a, antenna ; pi, palpus ; pr, 
 proboscis. 
 
AETHROPODA 
 
 FIG. 20. Culex, male and female. Photograph, 
 three times natural size. 
 
 ponds and marshes. 
 Where draining is 
 impossible the larvse 
 have been killed by 
 pouring kerosene 
 over the water, which 
 prevents them from 
 getting any air. A 
 quart of the oil is 
 sufficient for an area 
 of five hundred 
 
 square feet. It should be applied every two weeks during 
 warm weather. Cuba spent a hundred thousand dollars 
 in one year to control 
 the mosquito pest, and 
 as a result Havana was 
 freed of yellow fever for 
 the first time within a 
 hundred years. Experi- 
 ments conducted in my 
 laboratory show that 
 most ponds may be kept 
 free of mosquitoes by 
 introducing into them 
 newts, blunt-nosed sala- 
 manders, fish, or dragon- 
 fly larvse. 
 
 The crane flies resem- 
 
 FlG. 21. Blood corpuscles of a patient with 
 malarial fever. Two corpuscles contain the 
 parasites. Photograph, enlarged one thou- 
 sand diameters. 
 
 ble the mosquitoes, but 
 
 most of them are much larger and they have no 
 
 scales on the wings, the sure mark of a mosquito. The 
 
DIPTERA 
 
 45 
 
 FIG. 22. Wing of a mosquito. Photographed through the microscope to show the 
 scales. 
 
 crane flies are easily recognized by their long brittle legs 
 and long neck. The larvae 
 of many species do some 
 damage among the roots of 
 
 House Fly (Musca 
 Domestica) 
 
 This nuisance is found in 
 most parts of the entire world. 
 Recently it has been shown 
 that its natural breeding place 
 is in the manure thrown out 
 
 FIG. 23. Crane fly. Photograph, nat- of horse S tables. The hun- 
 ural size. , , , . , , 
 
 dred or more eggs deposited at 
 
 intervals by a female, hatch in from six to twelve hours 
 into white pointed larvae called maggots. These molt 
 
46 
 
 ABTHBOPODA 
 
 twice and attain full size in from four to eight days, 
 whereupon the outer skin hardens, swells out, and turns 
 brownish to form cases within which the pupae trans- 
 form in from four to eight days into the adults. 
 
 If boards of health would compel the frequent removal 
 of horse manure from the vicinity of towns the fly nuisance 
 might be greatly abated. About one fifth of the soldiers 
 in the national encampment in 1898 developed typhoid 
 
 FIG. 24. Common fly, its pupa, larva, and eggs. Photograph, twice 
 natural size. 
 
 fever, which was undoubtedly transmitted in some cases 
 by flies. These insects visit unclean places and thus carry 
 the germs on their feet to distribute them later as they 
 walk about over our food. I have found more than a hun- 
 dred germs (bacteria) clinging to the feet of one fly. 
 
 The house fly never bites, but before a rain the stable 
 fly (stomoxys), seen in large numbers on the cows, enters 
 the house and frequently bites human beings. Other 
 relatives of the house fly are the blowfly or blue-bottle 
 
DIPTERA 
 
 47 
 
 fly, which lays its oval white eggs on decaying meat, 
 where the larvae (maggots) complete their growth in about 
 ten days; the screw-worm fly, usually breeding in putre- 
 fying flesh, but sometimes in sores on animals and even 
 human beings; and the cabbage fly, whose maggot lives in 
 the roots of young cabbage and cauliflower in early sum- 
 mer, causing great loss to these crops. 
 
 Other Important Flies 
 
 Tachina Flies. All of the numerous species of the 
 Tachinas are beneficial, as their larvae feed on the larvae 
 of harmful insects such as caterpillars 
 and cutworms. The surest way to 
 secure specimens is to look for the 
 minute oval eggs glued to the skin of 
 a caterpillar, which should be fed in 
 a box containing an inch or two of 
 
 ,-, mi- ilAr FlG - 25. Photograph of 
 
 earth. The little maggot emerging a Tachina fly. Twice 
 
 from the lower side of each egg 
 
 penetrates the host and feeds on its fatty matter a week 
 
 FIG. 26. Photograph of four eggs of a Tachina on a larva of a Catalpa moth. 
 Natural size. 
 
 or two, after which it comes forth and remains several days 
 on or near the surface of the ground, a quiescent pupa 
 
48 ARTHROPODA 
 
 within its hardened brown skin. In the mean time trans- 
 formation to the adult fly occurs, and the skin is then rup- 
 tured for its exit. 
 
 Howard says he has seen millions of the army worm at 
 work and not a single individual could be found which did 
 not bear Tachina eggs. One great outbreak of the army 
 worm hi Alabama in 1881 was completely frustrated by 
 
 the Tachina flies and 
 a few other parasites. 
 Syrphus Flies. 
 These are found 
 among the flowers 
 and shrubbery in the 
 bright sunshine. 
 
 FIG. 27. Syrphus flies. Photograph, natural size. ,, ,, ., 
 
 They resemble the 
 
 bees and the wasps, though many of them are as small as 
 the house fly, and are often marked with orange or yellow- 
 ish bands on the abdomen. The larvae of some species 
 may be found feeding on plant lice, while others live on 
 decaying wood and manure. At least one, the drone fly 
 (Eristalis tenax), breeds in decaying flesh, where its larva 
 is known as the rat-tailed maggot. The idea prevalent, 
 that carcasses of animals may generate swarms of bees, 
 arose from the fact that the drone fly closely resembles 
 the honey bee. The story of Samson in the Book of 
 Judges relates such an incident. 
 
 Botflies. The several species of these are parasites 
 of vertebrates. The botfly of the horse (Gastrophilus equi) 
 is familiar to all who have been about horses in late summer 
 and noticed a large fly similar to a honey bee depositing 
 minute yellowish elongate eggs on the fore legs of the horse. 
 
DIPTERA 
 
 49 
 
 FIG. 28. Botfly of the horse, 
 larva and adult. Natural size. 
 After Selenka. 
 
 Later these are licked off by the animal and taken into 
 
 the stomach, where they develop into grublike larvae. 
 
 After attaching themselves to the 
 
 walls of the stomach, they are 
 
 nourished by the blood and lymph 
 
 of the host until the following 
 
 spring, when they pass on through 
 
 the canal, burrow into the ground, 
 
 and transform into the adult 
 
 about two weeks later. Bots 
 
 are sometimes fatal to the 
 
 horse. 
 
 The ox warble or heel fly (Hypoderma lineata) is a 
 pest to cattle raisers. The eggs deposited in the hair 
 are licked off by the cow, and immediately hatching pene- 
 trate the esophagus to wander several months among 
 
 the tissues, finally 
 reaching their des- 
 tination beneath 
 the skin on either 
 side of the back- 
 bone. The lumps 
 in these regions in 
 spring and early 
 summer reveal the 
 presence of the in- 
 sect. In late sum- 
 mer the maggot 
 emerges, drops to 
 the ground, and transforms to the adult. Stratton estimates 
 that this parasite in the United Kingdom causes a loss of 
 
 FIG. 29. Ox warble or heel fly. a, adult ; i, larva 
 removed from beneath the skin of the cow. Nat- 
 ural size. From Insect Life. 
 
50 
 
 ARTHROPODA 
 
 forty million dollars annually. The presence of these 
 grubs in an animal produces holes in the hide and renders 
 the meat along the back unwholesome. From January to 
 June fifty per cent of the cattle received in the Union Stock- 
 yards at Chicago are thus affected. 
 
 Hessian Fly. The Hessian fly (Cecidomyia destructor) 
 is familiar to most agriculturists through its ravages on 
 the wheat crop. It is supposed to have been introduced 
 into this country on the straw brought over by the Hessian 
 
 troops in the Rev- 
 olutionary War. 
 Specimens for 
 study are easily 
 secured by examin- 
 ing affected wheat 
 fields in May, June, 
 July, November, or 
 December. There 
 
 FIG. 30. Photograph of the Hessian fly, twice natural are tWO genera- 
 size. The flaxseed or pupa is at the base of a stalk , rpr 
 of wheat from which the leaves are stripped down. 1S a year. 
 
 minute reddish eggs 
 
 are laid in the spring on the upper surface of the leaves, 
 where a fortnight later they hatch into wormlike larvae. 
 By June they attain a length of a fourth of an inch, and 
 transform to the flaxseed or pupa between the leaves and 
 the stem at its base. The stalks affected are in an in- 
 clined or brokendown condition. The adult fly emerges 
 from the pupa case in August or September ready to ovi- 
 posit on the fall crop wherein the pupae remain during the 
 winter. This insect annually damages the wheat crop to 
 the extent of forty millions of dollars. 
 
DIPTERA 
 
 51 
 
 Other pests closely related to the Hessian fly are the 
 wheat midge, feeding upon the kernels of grain, the clover- 
 seed midge, whose larvse destroy the growing seed of the 
 clover, and the pear midge, feeding in young pears. 
 
 Though the word "Diptera" signifies two wings, yet 
 there are a few members of the order like the fleas which 
 have lost their wings 
 because of their par- 
 asitic habits. The 
 sheep tick dwelling 
 in the wool of the 
 sheep, the louse par- 
 asite on the honey 
 bee are also exam- 
 ples of wingless flies. 
 
 Nearly all of the 
 Diptera have a com- 
 plete metamorphosis, i.e., exhibit four stages in their life 
 history. Most species deposit eggs, but a few, such as the 
 flesh flies, bring forth their young alive. The larva in this 
 order is an active wormlike creature which in some species, 
 such as the mosquito, buffalo gnat, and horse flies, dwells 
 in the water, while in others it lives in decaying matter or 
 is parasitic in plants or animals. The larva sheds its skin 
 (molts) two or more times, and usually the skin shed last 
 forms a kind of case in which transformation to pupa and 
 from pupa to adult occurs. The life of the adult insects 
 of this order is seldom longer than a few weeks, but some 
 species such as the house fly and certain mosquitoes live 
 in a dormant state for several months during the cold 
 season and become active in the spring. 
 
 FIG. 31. Common dog or cat flea (Pulex serrati- 
 ceps). Photograph, enlarged thirty diameters. 
 
52 ARTHROPODA 
 
 3. HYMENOPTERA 
 
 The members of this order are readily distinguished 
 from other insects by the presence usually of four scale- 
 less transparent wings of which the hinder pair is the 
 smaller. The sting present at the end of the abdomen in 
 the females of many species is a structure not possessed by 
 the members of any other order. 
 
 Honey Bee (Apis mellifica) 
 
 Honey bees are social insects, dwelling in colonies com- 
 posed of three kinds of individuals. The males perform no 
 work and are therefore called drones. The imperfectly 
 developed females are named workers, because they per- 
 form all the labor. The perfect females of which only one 
 is allowed to remain in a hive are the queens. They do 
 nothing but lay the eggs. A colony after taking possession 
 of a hive or hollow tree forms out of wax secreted by the 
 
 FIG. 32. Photograph of honeybees natural size, a, drone; b, worker; c, 
 queen. 
 
 workers a comb of many hexagonal cells. During the 
 summer many of these cells are stored with honey for food 
 
HYMENOPTERA 
 
 53 
 
 FIG. 33. An egg, four larvae, aad 
 two pupae of the honey bee in 
 their cells. Natural size. 
 
 in winter. This is not found in flowers, as is generally 
 supposed, but is manufactured 
 by the bees from nectar 
 produced by glands in the 
 flower. The nectar passes into 
 the honey stomach where cer- 
 tain secretions act on it before 
 it is regurgitated into the cells 
 of the comb. 
 
 The amount of work accomplished by a hive of bees 
 is wonderful. A single swarm 
 has been known to collect 
 thirty-two pounds of material 
 in a day and some swarms of 
 the Cyprian breed have pro- 
 duced one thousand pounds of 
 honey each in a season. The 
 usual yield for a colony is less 
 than a hundred pounds annually. 
 Some of the cells are used for 
 breeding purposes. The queen 
 seems able at will to lay eggs 
 that will produce either drones 
 or females. The eggs destined 
 to become queens are laid in 
 larger cells, and the larvse, foot- 
 less white grubs, are furnished a 
 specially nutritious diet. 
 
 Honey bees are valuable not 
 only for the honey and wax pro- 
 duced, but also as a means of cross-fertilizing flowers. 
 
 FIG. 34. Alimentary canal of a 
 honey Dee. st, honey stomach ; 
 s, true stomach ; nt, intes- 
 tine ; o, esophagus ; sg, salivary 
 glands ; fc, kidneys. Enlarged 
 six diameters. 
 
54 
 
 ARTHROPODA 
 
 FIG. 35. Flower with one petal turned down 
 to show the single female organ, the pistil, 
 projecting a quarter of an inch above the 
 several male organs, the stamens. 
 
 Usually blossoms con- 
 tain within the showy 
 colored cup a central 
 pinlike filament, the fe- 
 male organ, or pistil 
 surrounded by several 
 threadlike filaments with 
 elongated heads giving 
 off a fine powder, the 
 male elements called pol- 
 len, which by coming in 
 contact with the pistil 
 causes it to produce 
 seeds and fruit. Ex- 
 periments have shown 
 that when the bees transfer the pollen from one blossom 
 to another more fruit and of much finer quality results 
 than if the pistil is fertilized by the pollen of the same 
 blossom. 
 
 Bumble Bee (Bombus fervidus) 
 
 The common bumble bee belongs to a group of social 
 bees dwelling in communities of rather limited numbers. 
 Early in the spring the queen, the only one of the colony 
 living through the winter, constructs waxen ovoidal cells 
 in an abandoned mouse's nest and lays eggs hatching into 
 workers. These like the honey bees are imperfect females 
 and much smaller than the queen who no longer collects 
 food but attends to home duties consisting mostly of egg 
 laying. In July some of the eggs are infertile and there- 
 
HYMENOFrERA 
 
 55 
 
 FIG. 36. Photograph of bumble bees, a, queen; 6, worker; c, drone. Natural 
 
 size. 
 
 fore hatch into males also called drones. These fertilize 
 a few of the queens hatching late and at the beginning of 
 winter die, as do also all the workers. 
 
 Wasps 
 
 Among the wasps are both social and solitary forms. 
 The common bald-faced hornet (Vespa maculata), the 
 yellow jacket (Vespa germanica), and the familiar paper 
 
 wasp (Polistes) all have a 
 life history similar to the 
 bumble bee. The sand 
 wasps and mud wasps are 
 solitary forms of much the 
 same habits. The latter 
 construct mud cells side by 
 side against the walls or 
 
 FIG. 37. Yellow jacket. Photograph, 
 natural size. 
 
 ceilings of a building and 
 after depositing an egg in 
 each cell stored with several paralyzed spiders or other 
 small insects seal it. The mother paralyzes the insects 
 
56 ARTHROPODA 
 
 intended for food for her young by stinging them in a chief 
 nerve center. To find the young and their food the nests 
 should be examined in May or June. The adult mud wasp 
 may be recognized by the threadlike connection between the 
 thorax and abdomen. 
 
 Ants 
 
 The numerous species of ants are distinguished from 
 the other members of the order by one or two swellings on 
 the slender stem (petiole) connecting the thorax and ab- 
 domen. They dwell in communities in which there may 
 be as many as five different castes or forms. In addition 
 to the ordinary winged males and females, there are two 
 kinds of workers, and the soldiers adapted for fighting. 
 
 FIG. 38. Photograph of ants, a, cocoon containing a larva ; 6, larva ; c, pupa ; 
 d, adult worker ; e, queen. About natural size. 
 
 The workers as with the bees are undeveloped females 
 which never possess wings. The true females or queens 
 have wings in the early part of the year until after the 
 nuptial flight, at the end of which they tear them off and 
 seek places to lay their eggs beneath stones, in decaying 
 wood, or under the bark of trees. 
 
HYMENOFIERA 
 
 57 
 
 Ant nests are easily found in decaying logs and under 
 stones and boards during the summer and autumn months 
 containing eggs, larvse, pupse, workers, and queens. The 
 eggs are white, just visible to the naked eye, and the larvse 
 may be distinguished from the pupse sometimes encased in 
 cocoons, by the ab- 
 sence of legs. 
 
 The favorite food 
 of some ants is the 
 honey dew ex- 
 creted by plant lice 
 from the alimen- 
 tary canal. Most 
 ants are fond of 
 any kind of sweets 
 and sometimes 
 cause much annoy- 
 
 i FIG. 39. Wheat plant louse enlarged 
 
 ance in houses. 
 They are easily got 
 rid of by sprink- 
 ling places frequented by them with a mixture of four 
 parts pulverized sugar and one part arsenic. More than 
 two thousand species of ants have been described. A 
 half dozen different species may be found in almost any 
 locality. 
 
 Sawflies 
 
 The sawflies are so named because of the structure of 
 the ovipositor which contains two saws capable of being 
 moved up and down to make apertures in vegetable tissue 
 to receive the eggs. The habits of these insects which are 
 
 about five 
 
 times, a, winged female; d, wingless female with 
 a hole from which a parasite escaped; b, young louse. 
 After Biley. 
 
58 
 
 ARTHROPODA 
 
 not true flies are easily 
 learned from observing 
 the common currant 
 worm ( Nematus ri- 
 besii). The minute 
 elongate eggs are de- 
 posited on the under 
 sides of the currant 
 leaves and gooseberry 
 leaves in May and June 
 where they hatch into 
 yellowish green cater- 
 pillarlike larvae attaining their full size of an inch in about 
 two weeks. They then drop to the ground, and just be- 
 
 PlG. 40. Photograph of currant sawfly, and co- 
 coon dug from the ground. Twice natural size. 
 
 FIG. 41. Photograph of a leaf of currant with eggs of the sawfly in their charac 
 teristic location along the veins. Twice natural size. 
 
 neath the surface form cocoons from particles of earth 
 within which they transform to pupae and a few days later 
 
HYMENOPTERA 
 
 59 
 
 to the adult form. Of the two generations in the year, 
 the one going into the cocoon state later remains therein 
 over winter. The easiest way to study the life of this in- 
 sect is to place in a box an inch layer of quite moist soil 
 and several larva?, which must be fed twice daily for about 
 a week until they disappear in the dirt. At intervals of 
 three days different cocoons should be opened to note the 
 progress of the transformation from the larvse to the adult 
 state, occupying about a fortnight. 
 
 The sawflies numbering two thousand species cause an 
 immense amount of 
 damage. One kind 
 defoliates the larch, 
 another the elm, while 
 the common rose slug, 
 the larva of a small 
 sawfly, causes havoc 
 to the rose bushes. 
 
 FIG. 42. Photograph of the currant worm. 
 Natural size. 
 
 The slimy dark-olive 
 
 pear slug, common on 
 
 the under side of the 
 
 pear, cherry, and plum leaves in early summer, winters 
 
 in a cocoon under ground and transforms to a sawfly the 
 
 following spring. All the larva? are easily destroyed by 
 
 dusting the plants with hellebore. 
 
 Gallflies 
 
 The gallflies, more properly called wasps, as they have 
 four wings, are minute insects about a quarter inch long 
 with many-jointed antennae and a chunky abdomen. 
 They derive their name from the fact that most of the 
 
60 
 
 ARTHROPODA 
 
 fifteen hundred species lay their eggs in 
 some part of a plant, and the develop- 
 ing larvaB by their excretions cause 
 an overgrowth of tissue producing an 
 enlargement called a gall. The oaks 
 are most frequently affected. Each 
 species forms its characteristic gall 
 FIG. 43. Photograph an d always on the same kind of plant, 
 of oak gaiifly en- ^ g^i opened hi May or June will 
 
 larged twice. . ..,.", 
 
 usually contain a single wormlike white 
 larva. The flies may be secured from many of the galls 
 by tying a piece of cheesecloth over them in early June 
 
 FIG. 44. On the left three galls or oak apples, of which two are cut open, a, 
 larva. On the right an oak gall about one month old. Photograph by Overton. 
 
 or by merely collecting them about the middle of June 
 and placing in a tight box until the flies appear. Some- 
 
HYMENOPTERA 
 
 61 
 
 times, instead of the expected gall insects, a number of very 
 minute Chalcis flies appear. These in their larval stage 
 are parasites on the gallflies (Fig. 59). 
 
 Galls used in the making of ink and tannic acid are pro- 
 duced by a species of Cynips on the oaks of Asia and 
 Europe. A few of the Diptera, many of the Hemiptera, 
 and some of the Arachnida also produce galls. The maple 
 spot gall, so common on the leaves of the red maple, is 
 made by the fungus-gnat (Sciara) of the order Diptera. The 
 conical gall of the witch-hazel is produced by a plant louse, 
 as is also the cockscomb gall on the elm leaves. 
 
 FIG. 45. Blackberry knot 
 gall common on the stems 
 of the blackberry. Nat- 
 ural size. 
 
 FIG. 46. Maple spot gall produced by 
 a fly. 
 
 Fig Producers. The fig insect (Blastophaga grossorwn) 
 is the most valuable member of the gall family, as with- 
 
ARTHROPODA 
 
 out its presence it is impossible to produce a first-class fig 
 at a reasonable price. Only since the year 1900 has the 
 secret of growing high-grade figs been utilized in this coun- 
 try. The Smyrna fig cultivated hi California bears only 
 
 a b d 
 
 FIG. 47. Figs, a, and d t unfertilized ; 6 and c, fertilized. After Howard. 
 
 female flowers within the hollow globular receptacle form- 
 ing the flesh of the fig. The fig will lack the desired flavor, 
 
 sweetness, and size un- 
 
 less it is fertilized, i.e., 
 unless pollen from male 
 fig flowers is carried 
 through the minute 
 orifice at the point op- 
 posite the stem and 
 distributed over the fe- 
 male flowers, causing 
 them to produce seeds. 
 The wild figs have both 
 lands of flowers, and 
 when these are planted 
 near the Smyrna fig 
 
 trees the fig insects emerging from the galls surrounded by 
 male flowers carry with them some pollen on the wings 
 
 FlG. 48. Photograph of the cut surface 
 of a wild fig showing over twenty galls : 
 a, place where the insect enters the 
 young fig to lay eggs. 
 
HYMENOPTERA 
 
 63 
 
 and legs as they pass out. At once they enter another 
 fig to deposit eggs. If this is a Smyrna fig, its female 
 flowers will be dusted with pollen from the insect and 
 
 FIG. 49 Fig insects; a, female; e, emerging from a gall, many of which are 
 seen in Fig. 48. Lines at right show natural size. After Howard. 
 
 thereby fertilized. The insect will not lay eggs in the 
 Smyrna fig, but only in the wild fig; therefore one indi- 
 vidual may carry the pollen to a dozen Smyrna figs be- 
 fore finding a wild fig whose character it does not recog- 
 nize before entering within the receptacle. 
 
 Ichneumon Flies 
 
 The ichneumons are incorrectly called flies, as they have 
 four wings. They go a step further in parasitism than the 
 preceding group, as they are parasitic on or within other 
 insects and usually while the latter are in the larval or 
 pupal stage. There are over five thousand species vary- 
 ing in size from an eighth of an inch to one and a half 
 
64 
 
 ARTHROPODA 
 
 inches in length. They may be recognized by the division 
 of the under side of the last segment of the abdomen, the 
 attachment of the ovipositor before the tip of the abdo- 
 men, and usually the heavy marginal vein of the front 
 
 wings with a dark 
 spot near its 
 middle. Pimpla 
 inquisitor is a 
 widespread para- 
 site of the tent 
 caterpillar, army 
 worm, tussock 
 moth, and fall 
 web worm. It de- 
 posits from five 
 to ten eggs be- 
 neath the skin of 
 its victim, within 
 which the larvsa feed a few days until they attain adult 
 size. They then emerge and spin their cocoons in a 
 bunch wherein transformation to the adult occurs. 
 
 In the autumn of 1901 fall webworms were so numer- 
 ous in Eastern Pennsylvania that scarcely a tree was to be 
 found that did not harbor from a dozen to a hundred. 
 They crawled over the sidewalks and crept up the houses. 
 In late autumn they formed cocoons of which I collected 
 a large number, and in over ninety per cent of them the 
 insect had been devoured by the larvae of the Pimpla. As 
 a result, the webworms instead of being numerous the 
 following season were very few. 
 A small ichneumon often attacks the large green tomato 
 
 FIG. 50. Pimpla inquisitor, an ichneumon, enlarged 
 about three times. 
 
FIG. 51. Bunch of Pimpla cocoons removed from the cocoon of the fall webworm, 
 and the larval parasite. 
 
 FIG. 52. Photograph of ichneumon larvae issuing from the Catalpa caterpillar. 
 Natural size. 
 
 FlG. 53. Photograph three hours later of the same caterpillar as shown in 
 Fig. 52. Slightly enlarged. (65) 
 
66 
 
 ARTHROPODA 
 
 PIG. 54. One of the many adult 
 insects that came from the cocoons 
 shown in Fig. 53. Enlarged six times. 
 
 FIG. 55. Photograph of Ophion. Nat- 
 ural size. 
 
 worm upon which its cocoons may be seen in late summer 
 or autumn. A simi- 
 lar species is para- 
 sitic in the larva of 
 the hawk moth feed- 
 ing on the leaves of 
 the Catalpa tree in 
 September. Ophion 
 and Trogon are two 
 of the large forms 
 often issuing from 
 the cocoons of the 
 swallowtail butter- 
 flies. Thalessa is 
 distinguished by its 
 long ovipositor used 
 in depositing eggs an inch or two within a tree where 
 
 FIG. 56. Photograph of Thalessa; o t the ovi- 
 positor equal in length with the two supports 
 was inserted two inches in an ash tree, and was 
 broken in the attempt to remove it. 
 
HYMENOFrERA 
 
 67 
 
 FJG. 57. Thalessa boring in an ash tree to 
 deposit its eggs in the burrow of a horn-tail 
 larva, a wood borer. Photograph, nat- 
 ural size. 
 
 the larvae may feed on 
 wood-boring larvae. . Ich- 
 neumon flies render great 
 service to agriculture by 
 keeping in check the 
 harmful caterpillars. 
 
 Chalcis Flies 
 
 The chalcids have 
 habits similar to the ich- 
 neumons from which they 
 may be distinguished by 
 the outward bend of the 
 antennae and the almost 
 entire absence of veins 
 
 in the fore wings. They are all small, being from an eighth 
 of an inch to a fourth of an inch long. Large numbers of 
 
 them may be se- 
 cured by collecting 
 a dozen or two 
 cabbage worms 
 (Fig. 67) in au- 
 tumn and feeding 
 them daily with 
 fresh cabbage 
 
 FIG. 58. A bunch of five chalcid larvae on the canker i WitViin 
 
 worm. Photograph, twice natural size. leaves. 
 
 a week chalcid 
 
 larvae will be seen to issue from several and spin cocoons 
 immediately in which they may remain all winter or if early 
 in the season transform to pupae and adults in about two 
 weeks. Three out of every ten oak galls in late summer 
 
ARTHROPODA 
 
 contain Chalcis larvae which have devoured the gallfly 
 larva. Some chalcids lay their eggs on the skin of the 
 host as in the case of Euplec- 
 trus (Fig. 58), while others 
 insert the eggs within the tis- 
 k sues and the larva? do not 
 
 Jfc AK appear on the surface until 
 
 ^11 they are ready to spin their 
 
 cocoons. 
 That the chalcids are most 
 
 FlG. 59. Chalcids transformed 
 from the larvae shown in Fig. 58. 
 Photographed nine days after Fig. 
 58. Enlarged eight times. 
 
 effective helps to man may be 
 seen from the fact that in one 
 year in the cotton fields of 
 Florida ninety-five per cent of 
 
 the eggs from which would have hatched the destructive 
 cotton caterpillar were killed by a species of Chalcis. 
 
 4. LEPIDOPTERA 
 
 This order includes the butterflies and moths, which are 
 readily distinguished from other insects by the presence 
 of two pairs of wings covered with scales. In a few species 
 the female has no wings. Butterflies usually fly by day 
 and moths by night. When resting the wings of a butter- 
 fly are held vertical over its back, but a moth at rest 
 holds its wings expanded or lying flat on its back. The 
 antennae of a butterfly are clubbed or enlarged at the 
 end, while those of a moth taper and are often feathered 
 throughout. The larvae of butterflies never construct co- 
 coons, while those of most moths spin or weave cocoons 
 for the pupal stage. 
 
LEPIDOPTERA 
 
 Butterflies 
 
 The seven hundred species of butterflies in North Amer- 
 ica, distributed from Central America to the Arctic Circle, 
 are chiefly of value to man through the pleasure and profit 
 they afford lovers of nature. Two or three species are de- 
 cidedly harmful hi the larval form. The two groups most 
 abundantly represented in the temperate zone are the 
 brush-footed tribe and the swallowtails. 
 
 Brush-footed Butterflies. This group, whose members 
 have imperfect fore legs, includes a number of common 
 
 FIG. 60. Photograph of two larvae and two adults of the Monarch butterfly. 
 One third natural size. 
 
 large forms. The milkweed butterfly or monarch (Anosia plex- 
 ippus) is quite as conspicuous as its black, white, and yel- 
 low-banded larva and bright green gold-spotted chrysalis 
 
ARTHROPODA 
 
 FIG. 61. Silver-spotted fritillary. Photograph, natural size. 
 
 FIG. 62. The mourning cloak. Photograph, natural size. 
 
LEPIDOPTERA 
 
 71 
 
 found on the milkweed from June till September. The 
 Silver-spotted fritillary (Argynis), whose larva feeds on 
 violets, and the mourning cloak (Vanessa antiopa), whose 
 larva feeds on willows and poplars, are easily secured for 
 study. The mourning cloak is the only kind of butterfly 
 frequently seen in February and March. 
 
 Swallowtails. The swallowtails and their allies making 
 
 FIG. 63 Common swallowtail, Papilio asterias ; A, larva; , preparing to 
 enter on the pupal state ; C, pupa as photographed twenty-four hours after. 
 
 up the family Papilionidae have six perfect feet, and most 
 of the swallowtails are characterized by a projection at the 
 
 posterior angle of 
 each hind wing. 
 They pass the win- 
 ter in the chrysalid 
 or pupal state, be- 
 ing always fastened 
 by a girdle near 
 the middle. The 
 larvae are naked 
 caterpillars, usu- 
 ally of a green 
 color, and feed upon a variety of plants. A most widely 
 distributed form is the cabbage butterfly (Pieris rapce), 
 
 FIG. 64. Photograph of the common swallowtail, 
 Papilio asterias. One half natural size. 
 
72 
 
 ARTHROPODA 
 
 FIG. 65. Photograph of the 
 larva of a tiger swallowtail. 
 Natural size. 
 
 whose life history may be studied 
 to the best advantage in late 
 summer and autumn. The spe- 
 cies was brought from England 
 to Quebec about 1860 in im- 
 ported cabbages. In three years 
 it had spread over an area of 
 sixty miles in diameter. By 
 1871 it was present throughout 
 eastern Canada and New Eng- 
 land. Ten years later it was 
 common from Hudson Bay to 
 Texas, and since 1895 it has 
 been a pest from the Pacific to 
 the Atlantic. 
 The green larvse are found from June to November by 
 
 noting on the cab- 
 bage plants the 
 
 dark shotlike ex- 
 cretions indicating 
 
 the presence of the 
 
 animals. Several 
 
 placed in a box 
 
 and fed daily with 
 
 fresh cabbage 
 
 leaves will within 
 
 a week or two form 
 
 cases of the last 
 
 molted skins and 
 
 change to the pupal 
 
 state, lasting in early summer but a few days, while later 
 
 FIG. 66. Photograph of pupal or chrysalitl case and 
 the black swallowtail that came from it. Two 
 thirds natural size. 
 
LEPIDOPTERA 
 
 73 
 
 it may continue 
 through the winter. 
 Some of the larvae 
 collected will be 
 found to be infested 
 with chalcid para- 
 sites which issuing 
 through the skin of 
 the host will spin 
 numerous small oval 
 cocoons thereon. A 
 larva thus affected 
 dies. 
 
 Moths 
 
 The Species Of the F IG . 6?. Photograph of cabbage butterfly and 
 
 moths are more larva> the latter enlar 8 ed twice - 
 
 numerous than the 
 
 butterflies, and some of them are great pests in the larval 
 form, though harmless in the imago (adult) state. A 
 brief description of one or more species of the nine most 
 important groups will give a clear idea of the relation of 
 these insects to man. 
 
 Hawk Moths (Sphingidae). The sphinxes are the 
 narrow-winged moths that visit the flowers at dusk and by 
 some are supposed to be humming birds. The tongue is 
 in some species four or five inches long, but is kept closely 
 coiled except when probing the flowers for nectar. The 
 larva is characterized by a horn on the top of the last seg- 
 ment, or in its place a glossy eye spot, giving it a formidable 
 
AETHROPODA 
 
 appearance though it is entirely harmless. It enters the 
 ground to pupate without spinning a cocoon. The cater- 
 
 PlG. 68. Photograph of the tomato- worm moth with its tongue uncoiled. 
 One half natural size. 
 
 pillar defoliating the Catalpa trees in September, the large 
 green tomato worm, and the tobacco worm often injuring 
 the tobacco crop, 
 are larva? of sphinx 
 moths. 
 
 Spinners (Bom- 
 bycidae). This 
 group is so named 
 because the larva? 
 spin cocoons in 
 which to pupate. 
 They are distin- 
 
 , FIG. 69. Photograph of tomato worm, the larva of 
 
 the the moth shown in Fig. 68. Two thirds natural size. 
 
LEPIDOPTERA 
 
 76 
 
 hawk moths by their hairy bodies, and pectinated or 
 feathered antennae. The larvae of the large forms are 
 
 FIG. 70. Photograph of the larva, pupa, and imago of the Catalpa sphinx (Cera- 
 tomia). Natural size. 
 
 called giant silkworms. Polyphemus is the American 
 
 silkworm. 
 The silk of commerce is produced by the domesticated 
 
 silkworm of China (Sericaria mori). In parts of China 
 
 the moths live in a wild state, but in several portions of the 
 
 Old World the in- 
 sect has been domes- 
 ticated. The entire 
 life history of the 
 moth may be ob- 
 served by any school 
 able to secure mul- 
 berry 
 
 FIG. 71. Photograph of a larva of polyphemus 
 (.Teleapolyphemus). Two thirds natural size. 
 
 or osage 
 
 orange leaves. If neither of these trees grows in the 
 locality, two or three white mulberry trees should be set 
 
76 
 
 ARTHROPODA 
 
 FIG. 72. Photograph of Polyphemus. Oue half 
 natural size. 
 
 out or seeds planted. The eggs of the silkworm moth 
 
 may be procured of T. Keleher, 662 Massachusetts Ave. 
 
 N. E., Washington, 
 D.C.; Dr. W. H. 
 Hill, Peoria, 111.; 
 and Mrs. Carrie 
 Williams, 1245 Lo- 
 gan Ave., San Di- 
 ego, Cal. If kept 
 cool they will not 
 hatch until late in 
 summer, but they 
 
 may be made to hatch during April or May by placing 
 
 them in a warm room a week. As soon as the minute 
 
 hairy black larvae 
 
 break from the eggs 
 
 they should be given 
 
 very small tender 
 
 leaves or larger 
 
 leaves cut into small 
 
 pieces. If fed sev- 
 eral times daily with 
 
 mulberry or osage 
 
 orange leaves for a 
 
 month, the larva will 
 
 spin a cocoon with 
 
 the secretion of the 
 
 silk glands opening 
 
 just beneath the 
 
 mouth. The spin- 
 ning occupies three days or more, and soon after its com- 
 
 FIG. 73. Photograph of cocoons of promethea 
 moth. 
 
LEPIDOPTERA 77 
 
 pletion the larva changes to a pupa which in a -week or 
 two is transformed to a white moth living only a few days 
 
 FIG. 74. Chinese silk worm spinning its cocoon of silk. Photograph, two thirds 
 natural size. 
 
 FIG. 75. Four stages of the Chinese silk worm. The moth has emerged from the 
 cocoon and laid some eggs on it. Photograph, natural size. 
 
 after emerging from its silken house. If the cocoons are 
 wanted for silk, a day or two after their completion they 
 are baked or steamed to kill the pupa. The thread form- 
 
78 
 
 ARTHROPODA 
 
 ing the cocoon is then wound off on a reel, and is often 
 found to be more than a mile long. Three thousand 
 cocoons are required to make a pound of raw silk, and 
 about ninety of the cocoon fibers as spun by the worm are 
 twisted together to make a thread of sewing silk. 
 
 The value of the silkworm was dis- 
 covered 1700 B.C. by the wife of the 
 third emperor of China, who is known 
 as the goddess of silkworms. For 
 nearly two thousand years, the Chinese 
 kept the method of obtaining silk a 
 profound secret. The penalty for 
 carrying the eggs out of China was 
 death. In 555 A.D., two Nestorian 
 monks were bribed by the Byzantine 
 emperor Justinian to bring him silk- 
 worm eggs concealed in the hollow of 
 their pilgrim staves. The industry then 
 spread rapidly throughout Europe, 
 and in 1622 reached America, but 
 owing to the high price of labor, the 
 
 na. 76. -snk glands of insect is not cultivated here to any 
 the silk worm. Natural great extent. From twenty-five thou- 
 sand to fifty thousand cocoons are 
 required to produce sufficient silk for a dress. 
 
 The forest tent caterpillar (Clisiocampa disstria) and 
 its cousin, the apple tree tent caterpillar, are the only larvae 
 which spin webs in the trees hi the spring. The larvae 
 break from the egg mass surrounding a twig, in early May, 
 and in a few days construct a tent to protect themselves 
 during the cold rainy weather. They grow to full size in 
 
LEPIDOPTERA 
 
 79 
 
 about a month, when they crawl to secluded places and spin 
 yellow cocoons from which the moths emerge two weeks 
 later and deposit four or five hundred eggs for the follow- 
 ing season. The Baltimore oriole is their greatest enemy. 
 The fallwebworm (Hyphantria textor)is the larva spinning 
 dense webs in the 
 trees from July to 
 September. It 
 passes the winter as 
 a pupa in its hairy 
 cocoon attached to 
 a limb or a leaf. 
 The white moth 
 comes forth the 
 following summer. 
 If these pests are 
 numerous one year 
 they are quite sure 
 to be scarce the 
 next, as the ichneu- 
 mon flies prey on 
 them extensively; 
 otherwise they 
 
 WOUld ruin tne Fm 77 ._ Tnree tents of tne tent caterpillar in a 
 autumn foliage Of tree which it has entirely stripped of leaves. 
 
 . the trees. 
 
 Tussock moths of several kinds consume the leaves of 
 the shade trees, but the " white-spotted " one (Notolophus 
 leucostigma) is the commonest. The hairy tufted red- 
 headed larvaB are found on the trees in June and July, and 
 also in September and October. There are two generations, 
 
80 
 
 ARTIIROPODA 
 
 FIG. 78. Photograph of tent caterpillars four days old on their tent. 
 Natural size. 
 
 the first of which hatches from the white frothy eggs de- 
 posited by the wingless female in late autumn and remaining 
 over winter on the trees. The eggs for the second genera- 
 tion are laid in late summer. In July and September, the 
 light yellowish cocoons an inch or more long are conspicu- 
 ous objects on the rough bark of the trees. 
 
 The gypsy moth (Ocneria dispar), occurring only in Massa- 
 chusetts and Rhode Island, was accidentally introduced 
 from France in 1868. The larva, a brownish hairy cater- 
 
LEPIDOPTERA 
 
 81 
 
 FIG. 79. Photograph of mature forest tent-caterpillars on their tent. One 
 third natural size. 
 
 pillar about an inch and a half long, feeds upon many kinds 
 of trees and plants. Had prompt measures been used in 
 the early seventies, the plague might have been exter- 
 minated, but owing to ignorance on the part of the legisla- 
 tors, no organized fight was made against the devastator 
 until 1890. For holding in check this pest, the Massa- 
 chusetts legislature appropriated in 1893 one hundred 
 
82 
 
 AKTHROPODA 
 
 FlG. 80. Eggs and moth of the tent caterpillar. Twice natural size. 
 
 thousand dollars, in 1894 the same amount, and the follow^- 
 ing year one hundred and fifty thousand dollars. Large 
 appropriations have 
 been made later, but 
 the enemy still con- 
 tinues its ravages, 
 and should it be 
 carried to the other 
 states a national 
 calamity would re- 
 sult. 
 
 Owlet Moths (Noc- 
 tuidae). These are 
 usually of a somber 
 gray or brown color 
 
 flnrl VmVP fl wino- P-X"- FlG - 81 '~ pll otograph of fal1 webworm and its co- 
 coon. Nearly twice natural size. 
 
 pansion of from one 
 
 to three inches. The larvae of many of the species are 
 
 known as cutworms, because in the spring and early 
 
LEPIDOPTEBA 
 
 FIG. 82. Photograph of pupa and 
 moth of the fall webwonn. Nat- 
 ural size. 
 
 summer they gnaw off 
 the corn, cabbage, cot- 
 ton, and other tender 
 plants near the surface 
 of the earth. Some spe- 
 cies climb the trees and 
 cut off the tender buds. 
 Both larvae and adults are usually active at night only. 
 The pupal stage is passed in the earth. In early spring the 
 common gray cutworm may be found coiled up under 
 
 FIG. 83. Female tussock moth which has 
 just emerged from the cocoon at the left 
 upon which it has deposited over two hun- 
 dred eggs. Photograph, slightly enlarged. 
 
 ElQ. 84. Larva of tussock moth. Photograph natural size. 
 
84 
 
 ARTHROPODA 
 
 stones and boards, while later it and allied species may be 
 found by digging about the base of any plant which has 
 
 lately been cut off near 
 the surface of the earth 
 Winter is passed in 
 the larval state, and 
 
 FIG. 85. Common cutworm (Agrotis), Nat- pupation OCCUrS in the 
 ural size. , 
 
 ground. 
 
 The cotton-boll worm or corn worm ( Heliothis armiger) in 
 1902 damaged the cotton crop in Texas alone to the extent 
 
 FIG. 87. Army worm, 
 natural size. 
 
 FIG. 86. Cotton-boll worm or corn worm. Two larvaj, 
 pupa, and adult. After Chittenden. 
 
 of four millions of dollars, and in 1893 to the extent of five 
 millions of dollars. It also attacks other plants, especially 
 the ears of sweet corn. The army worm (Leucania uni- 
 
LEPIDOPTERA 
 
 85 
 
 r'lG. 88. Photograph of the eggs, larva, and moths, male and female, ol the fall 
 canker worm. Enlarged slightly. 
 
 puncta) often travels in armies composed of millions of 
 individuals which destroy acres of vegetation in a single 
 day. The adult is a gray moth. 
 
 Measurers (Geometridae). The larvae of these moths 
 are called measuring worms, and may be distinguished by 
 their characteristic walk, which consists of attaching the 
 three front legs and then elevating the middle portion of 
 
86 ARTHROPODA 
 
 the body to form a loop as the hind legs are brought for- 
 ward. Of the many species the most injurious ones are 
 the canker worms. There are two kinds. The fall canker 
 worm (Anisopteryx pomclaria) ruins the leaves of the 
 orchards in certain localities in the northern parts of our 
 country during the month of June. The pupal state is 
 passed in the earth within a dense yellow silken cocoon, 
 
 FIG. 89. Photograph of a colony of oak-leaf rollers. One sixth natural size. 
 
 from which the moth comes forth in late autumn to deposit 
 three or four hundred eggs on the limb of a tree. The 
 female moth is wingless, and therefore the pest spreads 
 over new territory slowly'. The' spring canker worm, 
 similar to the fall species, is common in the Mississippi 
 valley and throughout the West. 
 
 Leaf Rollers (Tortricidae). These constitute a family 
 of rather small moths whose larvae often roll up the edges 
 of the leaves and line the interior with silk to form a cocoon. 
 Some species, such as the oak-leaf roller (Caccecia fervidana), 
 
LEPIDOPTERA 
 
 87 
 
 live in colonies forming webs in midsummer, within which 
 
 they pupate. 
 The coddling moth (Carpocapsa pomonelki) is familiar 
 
 to most pupils in its larval 
 
 form as the whitish worm 
 
 found in apples, pears, 
 
 and quinces. About a 
 
 Week after the trees bloom 
 
 the brownish-gray moth 
 
 emerges from its silken 
 
 cocoon beneath a loose 
 
 piece of bark and lays a 
 
 minute white egg on each 
 
 of fifty or more leaves and 
 
 apples. In less than two 
 
 weeks the larva enters 
 
 the fruit at the blossom 
 
 end and eats out a large cavity, causing it to fall to the 
 ground. Soon after, the worm finds a 
 secluded spot, constructs a cocoon in 
 which it remains a fortnight before 
 transformation to the adult moth is com- 
 pleted. In regions north of the latitude 
 of Buffalo the larva remains in its 
 cocoon over winter, but farther south 
 there are usually two generations and 
 the larva of late summer only remains 
 over winter. The pupa and adult are 
 
 easily obtained by removing a large larva from an apple 
 
 in June and feeding it daily in a covered jar with fresh 
 
 apple until it spins a cocoon. 
 
 FIG. 90. Photograph of half an apple con- 
 taining the larva of the coddling moth. 
 Nearly twice natural size. 
 
 FIG. 91. Coddling 
 moth. Photograph, 
 slightly enlarged. 
 
88 
 
 AKTHROPODA 
 
 FlG. 92. Larva of clothes moth( Tinea pellionella) 
 half out of its case. Photograph, three times nat- 
 ural size. 
 
 The damage this pest causes annually in Illinois has 
 been estimated at $2,375,000, in Nebraska $2,000,000, and 
 in New York $3,000,000. Not a state in the Union is 
 exempt from its ravages, which are somewhat limited by 
 the woodpeckers, and may be almost entirely avoided 
 
 by spraying the 
 trees in accord- 
 ance with direc- 
 tions furnished 
 by the United 
 States Depart- 
 ment of Agricul- 
 ture. 
 
 Tiny Moths (Tineidae). These are small moths with 
 pointed and fringed wings. Most important among them 
 are the clothes moths, of which there are two common 
 species. 
 
 The southern clothes moth (Tineola biselliella) is of a 
 pale-yellowish color without spots. Its larva, a hairless 
 white worm a half inch long, feeds upon museum speci- 
 mens, furs, feathers, 
 and hair. The ordi- 
 nary clothes moth 
 (Tinea pellionella) 
 may be distinguished 
 from the above species 
 
 i .-, -i -ii FIG. 93. Empty pupa case of the clothes moth. 
 
 by the less pointed 
 
 wings and the presence of a few dark spots on the anterior 
 wings. The white naked larva weaves a cocoon which is 
 carried about and enlarged to meet the growing demands 
 of the inmate. Finally within this cocoon the larva trans- 
 
LEPIDOPTERA 
 
 forms to the pupa, lasting about three weeks. The moths 
 emerge from May to August, take no food, and after de- 
 positing their eggs on any woolen material, soon die. The 
 larvae feed upon all sorts of woolen goods. In winter they 
 may be often found in their woven cases adhering by their 
 ends to the lids of boxes or the ceilings of rooms. 
 
 FIG. 94. Clothes moth (Tinea 
 pellionella). Photograph, 
 twice natural size. 
 
 FIG. 95. Moth of the 
 maple borer. Natural 
 
 Clear- winged Moths (Sesiidae). These are wasplike 
 moths of brilliant colors and have transparent wings. They 
 generally fly by day. Their larvse live in the stems of 
 herbs and shrubs or the trunks of trees. Usually each 
 species confines its depredations to a certain kind of plant 
 or tree. The empty pupa cases of the maple borer (Sesia 
 acerni) may be seen protruding from round holes in the 
 soft maples during the month of June. The squash borer 
 may often be found during early summer in dead and dying 
 squash, pumpkin, melon, and cucumber vines, just be- 
 neath or at the surface of the ground. It is a widespread 
 pest. 
 
 The moth of the peach tree borer (Sanina exitiosa) de- 
 posits during May, June, or July one or more yellowish 
 
90 
 
 ARTHROPOD A 
 
 almost invisible eggs on the bark of stone-fruit trees near 
 the ground. The white larva bores into the tree, feeding 
 on the sap wood near or below the surface of the ground, 
 and making its presence known by the exudation of gum 
 and fragments of borings about the base of the tree. By 
 late autumn it is almost an inch long, and it then remains 
 dormant until the following spring. The approach of 
 warm weather again stimulates it to feed a few weeks and 
 
 FIG. 96. Peach, tree borer ; a, female moth ; 6, male moth ; d and e, pupae ; c, lar- 
 , va ;/, chip cocoon with extruded pupa skin. Natural size, after Marlatt. 
 
 in late spring or early summer its transformation to pupa 
 and adult is accomplished witliin a chip and gum cocoon 
 at the base of the tree. 
 
 Metamorphosis among the Lepidoptera is complete, i.e., 
 there are four well-marked stages, the egg, larva, pupa, and 
 imago or adult. In some species the eggs hatch a few 
 hours after being laid, while in others they remain over 
 winter. The larva of most species, except those of the 
 measuring worms, have eight pairs of legs of which the 
 three anterior are known as true legs because they become 
 
LEPIDOPTERA 91 
 
 the legs in the imago. The others are called false or prop 
 legs. The larva is a voracious creature, often eating its 
 own weight of food in a day. Its senses of taste and feel- 
 ing are well developed, but the other senses appear quite 
 rudimentary. Three simple eyes on either side of the head 
 enable it to discern light from darkness. 
 
 The shedding of the skin, called molting, occurs usually 
 four or five times, and in many species the last larval skin 
 forms the cocoon in which transformation to pupa and 
 adult is effected. The larvae of the butterflies never spin 
 cocoons, but those of the moths, with the exception of the 
 ones pupating in the earth, generally form cocoons either 
 from the hair on their bodies or from the secretion of cer- 
 tain glands. The larval state in most species continues 
 one or two months, but in certain species it lasts more than 
 a year. In the pupal stage the insect appears as if dead. 
 Freezing temperature for months does not harm it. The 
 period during which the various species remain in this con- 
 dition is from a few days to a year. The imago of many 
 species takes no food, while in others, such as the hawk 
 moths and some butterflies, it sips nectar or sap through 
 its proboscis formed by the greatly developed maxilla?. 
 The mandibles which chew the food in the larval state are 
 too small for use. 
 
 5. HEMIPTERA 
 
 The members of this order are the true bugs whose mouth 
 parts are adapted for piercing and sucking. They can not 
 bite or chew. Nearly thirty thousand species have been 
 described, and among them are found the greatest enemies 
 of the human race. 
 
ARTHROPOD A 
 
 FIG. 97. Seventeen-year cicadas ascending an ash tree at 8 P. M. Flash light 
 photograph, one fourth natural size. 
 
HEMIPTERA 
 
 Harvest Flies (Cicadidae) 
 
 The cicadas, wrongly called locusts, are the largest repre- 
 sentatives of this order. The most celebrated of the several 
 species is the seventeen-year locust (Cicada septendecim) , 
 
 FIG. 98. Seven teen-year cicada showing metamorphosis from nymph to adult as 
 it occurred between the hours of 9 P. M. and 10.30 P.M. Flashlight photographs, 
 one half natural size. 
 
 which appeared in vast numbers in seventeen states during 
 1902. During the last days of May just at sundown under 
 the trees the numerous young, called 
 nymphs, peeped out of holes in the earth, 
 and a few minutes later came forth, walked 
 to the nearest tree, ascended some dis- 
 tance, and fixed their claws firmly in the 
 bark in preparation for molting. A fis- 
 sure appeared in the skin of the backs 
 from which issued the adult white cicadas. 
 The wings slowly expanded and the 
 changed creatures proceeded toward the 
 upper branches, where at daylight they 
 became of a dark hue and forced their beaks 
 through the tender bark in quest of sap. 
 In July the love song of the males, sounding much 
 like the rattle of the rattlesnake, made such a din in the 
 
 FIG. 99. Seven- 
 teen-year cicada. 
 Natural size. 
 
ARTHROPODA 
 
 FIG. 100. End of the ovipositor of a cicada showing below the two saws used to 
 make the insertion for the eggs. Photograph enlarged twenty times. 
 
 FIG. 101. Annual cicada with its beak inserted in 
 a twig. 
 
 forests that a person could not hear his companion 
 
 speak at a distance 
 
 of ten feet. The 
 
 noise is produced by 
 
 the drum present 
 
 only in the male 
 
 beneath the front 
 
 part of the abdo- 
 men. A few days 
 
 later the females 
 
 with the saws of the ovipositor cut slits in the tender 
 branches to deposit numerous eggs which 
 hatched a few days later, and the antlike 
 young descended into the earth to re- 
 main sixteen years feeding on the sap 
 in the roots or absorbing nourishment 
 from the humus in the soil. These 
 insects never sting, as many suppose, 
 and cause but little damage to trees. 
 
 FIG. 102. -Pupa skin The annual cicada (Cicada tibicen), 
 also known as the jar fly or dog-day fly, 
 
HEMIPTERA 
 
 95 
 
 because it appears in August, completes its life round in 
 only two years. The numerous pupal or nymph cases 
 seen on the trees in late summer are of this species. 
 
 Plant Lice (Aphidae) 
 
 The plant lice have a remarkable life history. Most 
 of them pass the winter in the egg state. At the first 
 
 FlQ, 103. Eggs of plant lice on a maple tree in October. Photograph three times 
 natural size. 
 
 appearance of leaves in the spring, the eggs hatch into 
 wingless females, no males being found until late in summer. 
 
96 
 
 ARTHROPODA 
 
 The females bring forth living young at the rate of from 
 three to ten daily for nearly a fortnight and sometimes 
 longer. In two weeks after birth the young generations 
 are sufficiently mature to become the mothers of several 
 daughters daily. Later in the season some of these develop 
 wings, and at the approach of cold weather males are born, 
 
 FIG. 104. Plant lice. Those on the left are enlarged twice, tho; 
 sucking juice are natural size. Photographs. 
 
 at ihe right 
 
 some of which also have wings. In October and Novem- 
 ber, the female deposits numerous fertile eggs which re- 
 main over winter and hatch into stem mothers the 
 following season. So rapidly do the plant lice breed that 
 were it not for their natural enemies, the birds, minute 
 parasitic flies, syrphus flies, and lady bugs, they would 
 destroy most of the vegetation. 
 
HEMIPTERA 
 
 97 
 
 The grape-vine louse (Phylloxera vastatrix) is said to have 
 cost the French more than the indemnity paid to the Ger- 
 mans after the Franco-Prussian war. Its damage in this 
 country is not great. 
 
 The hop louse (Phorodon humuli) is the great enemy of 
 the hop industry. Aphis rosce makes the raising of roses 
 
 FlG. 105. Grape-vine Phylloxera ; a, adult ; b, young. After Marlatt. 
 
 difficult in some regions. The maple louse blights young 
 maples. Aphis mail stunts many young apple trees. The 
 cherry aphis (Myzus cerasi) lives on the cherry from April 
 till June, and feeds on another plant the rest of the season. 
 The green pea louse along the Atlantic coast in 1900 de- 
 stroyed peas to the value of four millions of dollars. In 
 1899 the wheat louse damaged the wheat badly in many 
 sections. 
 
98 
 
 ARTHROPODA 
 
 The several species of Aphidse bearing a white cottony 
 growth are known as wooly plant lice. In all there are 
 over a thousand species of Aphidae. Many of them give 
 forth from the alimentary canal a honey dew much sought 
 after by the ants, which often care for the eggs and young 
 
 FIG. 106. Hop louse which lives on the plum tree in late fall, winter, and early 
 spring until the hop vines develop ; a, male ; b, female. Enlarged twenty 
 times. After Biley. 
 
 of the lice by carrying them from place to place and other- 
 wise protecting them. Plant lice are therefore spoken of 
 as the ants' cows. 
 
 Scale Insects or Bark Lice (Coccidae) 
 
 The individuals of this family are easily recognized by 
 the fact that the female and sometimes the male dwell 
 beneath a scale varying in size from one fiftieth of an inch 
 to a fourth of an inch in diameter. The scale is formed 
 by the molted skins and excretions of the insect. 
 
 Pernicious or San Jose Scale (Aspidiotus perniciosus.) 
 
HEMIPTEBA 
 
 This scale may be studied to the best advantage from July 
 to November. It is distinguished by its circular form with 
 a minute peak at the center, and a red color beneath the 
 
 FIG. 107. San Jose scale. The two limbs at the right are completely covered, 
 while the one at the left has only five large scales and several small ones. 
 Photograph ten times natural size. 
 
 bark or fruit supporting it. The scales may not be per- 
 fectly round, especially on the leaves, and the peak may 
 be absent on some of them. The insect winters in a half- 
 grown state, being a mere disk of yellow covered by a 
 minute black scale. It begins to feed in the early spring 
 by sucking the sap through its beak so tightly stuck in the 
 twig that it can never be withdrawn. By June numerous 
 young may be seen within the mother if examined under 
 
100 ARTHROPODA 
 
 the microscope, and during the latter part of the month 
 in the latitude of Pittsburgh they give birth to living 
 young which crawl out from the scale, and during the next 
 
 FIG. 108. San Jose scale on a pear. Photograph natural size. 
 
 two days appear to the naked eye as minute yellowish 
 specks slowly wandering over the branches. After a free 
 life of about forty hours, these Iarva3 insert the beak firmly 
 into the bark from which they never remove it. The 
 exudations of the insect's body form the scale. The young 
 are ready to reproduce in one month, and bring forth during 
 the next three weeks about five hundred living young. 
 
HEMIFPERA, 
 
 101 
 
 As from three to six broods mature during a season, a 
 single insect may be the mother of one hundred million 
 young from June to De- 
 cember. 
 
 Their only way of spread- 
 ing is by being carried on 
 the feet of birds, by various 
 insects, and by the wind. 
 The purchasing of infested 
 trees may also be the means 
 of introducing the pest into 
 a locality. It attacks most 
 fruit trees, currant bushes, 
 English walnut, osage 
 orange, and numerous other 
 shrubs, which are usually 
 killed within two or three 
 years by the poison in- 
 jected into them and the loss of the sap. The greatest 
 
 natural enemy 
 of this scale is 
 the two-spotted 
 ladybird beetle 
 brought by the 
 go vernmen t 
 agents from 
 China, the home 
 of the scale. Nu- 
 merous artificial 
 remedies, direc- 
 
 FIQ, 110. Male San Jose scale insect enlarged about ,- /. 
 
 fifty diameters. After Howard. tlOIlS 101 USlBg 
 
 PIG. 109. Female San Jose scale insect 
 removed from the scale. Several 
 young are seen within. Enlarged 
 fifty diameters. After Howard. 
 
102 
 
 ARTHROPOD A 
 
 which may be secured free from the United States 
 Department of Agriculture, will keep the pest in check. 
 
 FlG. 111. Asiatic lady- 
 bird imported to de- 
 vour the San Jose 
 scale, c, larva ; /, 
 adult. Enlarged four 
 times. After Marlatt. 
 
 FIG. 112. Oyster-shell scales, three of which 
 have holes showing where Chalcis flies es- 
 caped after destroying the contents. Three 
 times natural size. 
 
 The oyster-shell bark louse (Mytilaspis pomorum) is not 
 so serious a pest as the pernicious scale. It brings forth 
 only one brood annually, and remains over winter in the 
 egg state. 
 
HEMIPTEKA 
 
 103 
 
 The scurfy bark louse, 
 with a scale twice as 
 long as wide, impover- 
 ishes the apple trees in 
 some localities. The 
 rose scale (Diaspis 
 rosce) is an enemy 
 of the roses and 
 blackberries, but it is 
 kept in check by para- 
 sites. 
 
 The armored scales 
 are represented by 
 the maple scale and the 
 poplar or tulip tree scale. 
 The covering of the in- 
 sect is not a true scale, 
 but a waxy secretion. 
 The common hothouse 
 mealy bug is also a fa- 
 miliar species of the 
 CoccidaB. The only 
 useful member of this 
 large family is the 
 cochineal insect (Coccus 
 cacti) feeding on the 
 cactus in Mexico, Cen- 
 tral America, and other 
 tropical regions. These 
 creatures are dried and 
 powdered to form the 
 
 FIG. 113. Rose scale. Large round ones are 
 females and the few small elongate ones are 
 males. .Enlarged thrfce times. 
 
104 
 
 ARTHROPODA 
 
 famous cochineal dye from which carmine is ex- 
 tracted. 
 
 The true bugs (Heteroptera) contain several species of 
 considerable interest to man. They possess a beak per- 
 mitting them to feed on the juices of plants or insects, or 
 
 FIG. 114. Maple 
 scale, five adults 
 and many young. 
 Photograph en- 
 larged twice. 
 
 FIG. 115. Bedbug viewed 
 from the side and back ; a, 
 beak used in piercing the 
 skin and sucking the blood. 
 Photograph enlarged twice. 
 
 on the blood of vertebrates. The wings when present 
 consist of two pairs. The anterior ones function as elytra 
 or covers, and have the basal half thickened, a feature from 
 which the name of the order, Hemiptera (half-winged), 
 is derived. 
 
 The bedbug (Cimex lectularius), found in all parts of the 
 world, is able to live a year or more without food. This 
 
HEMIPTERA 105 
 
 fact, together with its flat body permitting it to hide in 
 the smallest crevices, makes extermination difficult when 
 a house is once infested with them. As they have no 
 wings their usual method of entering a house is on articles 
 of clothing. The idea that they are associated with bats 
 and pigeons is a mistaken one, although a similar bug is 
 a parasite on the bats. 
 
 The assassin bugs, many of which have beaks strong 
 enough to pierce the human skin, include the kissing bugs. 
 Of these Reduvius personatus living in dirty basements 
 and feeding on bedbugs and roaches, is common throughout 
 this country. It is a fierce biter, occasionally attacking 
 man and sometimes causing serious sickness, owing to the 
 germs on the dirty beak. 
 
 The chinch bug (Blissus leucopterus) causes an annual 
 loss to the grain and grass crop of nearly twenty millions 
 of dollars. It passes the winter in 
 clumps of grass or other protected 
 places, and in the spring lays about 
 five hundred eggs in the grass sheaths 
 near the ground. The young as well 
 as the adults are gregarious. A 
 
 M 
 
 second generation develops from eggs FIG. ne. - photograph of 
 laid in August. The species occurs SJj*^ 8 " enlarged 
 over the entire eastern half of the 
 
 United States, but it is most destructive in the Central 
 States, the Carolinas, and Virginia. 
 
 The ill-smelling squash bug (Anasa Iristis) renders the 
 squash, melon, pumpkin, and cucumber crop an uncertain 
 one in many localities, while the harlequin cabbage bug 
 destroys millions of cabbage plants annually. The water 
 
106 
 
 AKTHROPODA 
 
 boatman (Notonecta) and the giant water bug (Belostoma) 
 are the two common aquatic members of this order. 
 
 The pupil must remember that there is a wide difference 
 between bugs and beetles both in their external appearance 
 and habits. The most significant difference in structure is 
 in the mouth parts, which should be examined in some large 
 bug such as the squash bug. In this species the piercing 
 
 FIG. 117. Squash bug viewed froiu the side and back; 6, beak used in piercing 
 and sucking the juice of the vines. Photograph enlarged three times. 
 
 and sucking beak is more than a quarter of an inch long, and 
 is folded close to the ventral side of the body when not in use. 
 At the base of the beak is the labrum, while in a groove on 
 its upper part lie two pairs of hairlike processes, the shorter 
 of which are the mandibles, and the longer are the max- 
 illaB. The sheath inclosing these is made by the labium 
 and labial palpi. The bugs are capable only of piercing 
 and sucking food, and can not bite. 
 
COLEOPTERA 
 
 ion 
 
 6. COLEOPTERA 
 
 The members of this order are distinguished by the pres- 
 ence of elytra (hardened wing-covers) which meet in a 
 straight line down the middle of the back. More than 
 one hundred thousand species are known. 
 
 The snout beetles or weevils (Rhyncophora) comprise over 
 four thousand species, all of which are injurious. The 
 plum curculio (Conotrechelus nenuphar) 
 is familiar to every one in its larval 
 state as the footless white grub present 
 in so many plums, cherries, and apricots, 
 causing the unripe fruit to fall to the 
 ground. The larva then enters the earth, 
 soon becomes a quiescent pupa, and a 
 fortnight later has completed its trans- 
 formation to an adult beetle. It may 
 be found on the plum and cherry trees from May until 
 August. An easy method of col- 
 lecting them is to hold an open 
 umbrella or sheet beneath the tree 
 and shake it vigorously. 
 
 The nut weevil (Balininus) is 
 easily recognized by its long snout. 
 Chestnuts harboring the larvse of 
 this weevil are spoken of as being 
 wormy. The eggs are laid in 
 August or September, and the 
 larvae leaving the chestnuts in late 
 FIG. 119. -Photograph of lar- autumn enter the ground to pu- 
 
 va and adult nut weevil en- . 
 
 hree times, pate and remain until the next 
 
 FIG. 118. Photograph 
 of plum curculio en- 
 arged three times. 
 
108 
 
 ARTHROPODA 
 
 FIG. 120. -Pea weevil ; a, adult ; 6, larva ; c,pupa. 
 Enlarged five times. After CMttenden. 
 
 season. The pea weevil (Bruchus) is often found in peas 
 
 in its larval state during summer and autumn, as a pupa 
 
 in winter, and in the 
 adult form in late 
 spring, when it comes 
 forth to lay its eggs 
 on the pods of the 
 growing peas. To 
 find the weevil in 
 the fall, soak peas 
 water for a day. 
 This causes most of 
 
 the affected seeds to float. The grain weevil (Calandra) is 
 
 a pest in mills and granaries, devouring the inside of the 
 
 grains of wheat. 
 The cotton-boll 
 
 weevil (Anthono- 
 
 mus grandis) 
 
 threatens to make 
 
 cotton raising a 
 
 very uncertain 
 
 business. The 
 
 pest became so 
 
 troublesome in 
 
 Texas that the 
 
 governor offered 
 
 a reward of fifty 
 
 thousand dollars FIG. 121. Cotton-boll weevil ; a, larva ; 6, pupa ; c, 
 tO any One Who adUlt ' ^tograph enlarged four times. 
 
 should discover a remedy to prevent the ravages of the in- 
 sect, which amounted to twenty millions of dollars annually. 
 
 
COLEOPTERA 
 
 109 
 
 The strawberry weevil (Anthonomus signatus) in certain 
 seasons has prevented the development of more than a 
 half crop of berries in New Jersey, Delaware, Maryland, 
 
 FIG. 122. -- Straw- 
 berry weevil en- 
 larged seven diam- 
 eters. Alter Chit- 
 tenden. 
 
 FIG. 123. Galleries of the spruce-destroying beetle 
 beneath the bark of a spruce tree. After Hopkins. 
 
 the Carolinas, and Virginia. The eggs are deposited in 
 the flower buds, upon which the grublike larva feed and 
 attain full size in about a month. 
 The bark beetles are short-snouted weevils which breed 
 
110 
 
 ARTHROPODA 
 
 just beneath the bark of many species of trees and exca- 
 vate characteristic galleries. It is estimated that they 
 damage timber to the extent of fifty millions of dollars 
 annually. 
 
 The Lamellicorn Beetles are characterized by antennae 
 ending in from three to seven flat segments. They are 
 much less destructive than the weevils. The commonest 
 
 FlG. 124. Pine-bark beetle whose work has made pine lumber expensive ; a, 
 adult ; c, pupa ; d, larva. Small figures are natural size. After Hopkins. 
 
 representative is the May beetle or June beetle (Lachnosterna 
 fusca) of a brown color and more than a half an inch long. 
 It is often attracted into the house at night by the lighted 
 lamp. The eggs are laid on grass near the ground where 
 they hatch into minute six-legged white grubs with brown 
 heads. They burrow into the earth, feed on the roots 
 of grasses for two years, and having attained a length of 
 nearly two inches are known to most people as white worms 
 or grubs. Transformation to pupa occurs in the fall and 
 the adult issues the following spring. The stag 
 
COLEOFFERA 
 
 111 
 
 (Lucanus dama) 
 presents a life 
 liistory similar 
 to the June 
 beetle, but the 
 larval and pupal 
 stages are passed 
 in decaying 
 wood. 
 
 TheLongicorn 
 Beetles (Ceram- 
 bycidce) form a 
 family including 
 eight thousand 
 species whose 
 larva? are wood 
 borers tunneling 
 through trees. 
 
 TVi orl If FlG. 125. Stag beetle; a, antenna ; e, eye; m, mandible 
 
 p, palpus. Photograph natural size. 
 
 characterized by 
 
 long, many-jointed antennse. The locust borer (Clytus 
 
 robinice), whose white, 
 grublike larva lives in 
 the locust tree, may be 
 found in September on 
 the golden rods. The 
 apple tree borer issues 
 as an adult from the 
 apple tree in July and 
 FIG. 126. Larva of the stag beetle. Black may be recognized by 
 
 spots on the side are spiracles. Photograph . ,, . , . ' 
 
 natural size. the two yellowish stripes 
 
112 
 
 ARTHROPODA 
 
 on its elytra. The pine tree borer may live in wood 
 made into furniture for fifteen years. The maple borer 
 destroys annually many maple trees. It is well for the 
 
 FIG. 127. Beetle of 
 the locust borer. 
 
 FlG. 128. Firefly or Lightning bug; a, larva; 6, 
 pupa ; c, adult. 
 
 pupil to remember that not only the larvae of many 
 beetles, but also the Iarva3 of some of tjie Lepidoptera 
 and Hymen optera dwell 
 within living trees. 
 
 The Serricorn Beetles 
 including several thou- 
 sand species, have ser- 
 rate antennae of me- 
 dium length. The larvse 
 vary in their habits. 
 The firefly or lightning 
 bug (Photinus pyralis) 
 passes its larval life in 
 the earth feeding on 
 
 ,, , -, FIG, 129. Click beetle and its larva, 
 
 earth WOrmS and SOtt- Slightly enlarged. 
 
 bodied insects. It pu- 
 pates in a cocoon of earth, and transforms to the adult 
 state in June, when it comes forth and flies about by night 
 emitting a strong light from the lower side of the posterior 
 
COLEOPTERA 
 
 118 
 
 part of the abdomen. The larva of a larger species lives 
 above ground and is known as the glow worm. 
 
 The click beetles, making up the family Elateridse, may 
 be recognized by the characteristic 
 click which they give to right them- 
 selves when placed on their backs. 
 The larvae, called wire worms, live under 
 the bark of trees, in rotten wood, or 
 upon the roots of herbs. They have 
 a rather hard, brownish skin and three 
 pairs of legs. They are plentiful and 
 easily found in rotten logs. In summer 
 and autumn the beetles feed on the 
 flowers. 
 
 TO, ni T> A i i, i. FIG. 130. Eyed elater, 
 
 The Clavicorn Beetles are character- the largest of the click 
 ized by club-shaped antenna. The be f les : . phot g ra P h 
 
 J natural size. 
 
 buffalo moth or carpet beetle (Anthrenus 
 
 scrophularice) is present in nearly every house with tacked- 
 
 FIG. 131. Buffalo moth or carpet beetle; a, larva; b, pupa within larva skin; 
 c, pupa ; d, adult. Enlarged eight times. After Riley. 
 
 down woolen carpets. The small larva bristling with brown 
 hairs may be found under the edge of a carpet not recently 
 
114 
 
 ARTHROPODA 
 
 FIG. 132. Museum pest (Anthrenus varius). Larva 
 below the open pupa case, and adult above. 
 Photograph enlarged three times. 
 
 cleaned, at almost any time of the year. It feeds on any 
 kind of woolen material. It is probable that there are two 
 broods a year, but the beetles are most frequently seen on 
 
 the windows in 
 April. A similar 
 beetle, the museum 
 pest (Anthrenus va- 
 rius), destroys 
 many kinds of 
 dried museum ma- 
 terial. Carbon bi- 
 sulphide, a fourth 
 of an ounce to each 
 cubic foot, will de- 
 stroy any of these 
 beetles or their 
 Iarva3 if the box or closet containing them is closed 
 tightly for a day. 
 The ladybird fam- 
 ily (CoccinellidcB), 
 containing about a 
 thousand species, 
 should be known 
 to every one, as 
 nearly all of its 
 members are 
 friends of man. 
 They are of a more 
 or less hemispheri- 
 cal form, and usually of a red or yellow color with 
 round or lunate black spots. The larvae, which are 
 
 FIG. 133. Ladybird beetle; a, larva; 6, pupa; c, 
 adult. Line at the right shows natural size. After 
 Chittenden. 
 
COLEOPTERA 115 
 
 most abundant in June and July, consume great num- 
 bers of plant lice. In some places in. California the de- 
 structive orange scale has been entirely kept in check 
 by a species of ladybird beetle, and lately 
 the Asiatic ladybird imported from China 
 is proving a great destroyer of the San 
 Jose scale. The beetles pass the winter 
 in the adult state, often coming into 
 houses, where they should be protected. Fm Larva 
 The Leaf-eating Beetles, numbering ten of ladybird bee- 
 
 ,, -. ... , tie twice natu- 
 
 thousand species, are injurious to garden raisize. 
 vegetables and many shade trees. The 
 best known of these are the Colorado potato beetle, the 
 asparagus beetle, and the elm leaf beetle, whose depredations 
 cost millions of dollars annually. The Colorado potato 
 beetle dwelt near the base of the Rocky Mountains until 
 1859 when it began to be a pest in the potato fields of the 
 western settlers. Having acquired the habit of feeding 
 upon the potato, it spread rapidly, reaching the Atlantic 
 coast in 1874. The pest is easily kept in check by spray- 
 ing the potatoes with Paris green and water or sprinkling 
 them with fifteen parts of flour to one part of Paris green. 
 The Coleoptera exhibit a complete metamorphosis, but 
 the forms and habits of the larvae vary widely. Some dwell 
 underground, some thrive on decaying wood, and some 
 prey on other insects. With the exception of the lady- 
 birds, and carrion beetles whose larvae feed on decaying 
 flesh, the members of this order are mostly injurious. 
 Instead of taking food by sucking, as is the habit of all the 
 bugs, they chew their food and are therefore readily killed 
 by spraying the vegetation with poisons. 
 
116 
 
 ARTHROPODA 
 
 7. NEUROPTERA, EPHEMERIDA, AND ODONATA 
 
 A typical example of the Neuroptera is the hellgramite 
 (Corydalis cornutus) whose larva, the black crab, or dobson, 
 
 is the f a v o r it e 
 among fishermen as 
 a bait for black 
 bass. It is found 
 under logs and 
 stones in the shal- 
 low water of clear 
 streams, which it 
 leaves in late spring 
 to hide under some 
 object on the bank 
 and to transform to 
 a naked pupa. A 
 week or more later 
 it assumes the adult 
 form which may 
 
 FIG. 135. - Catching the larv* of hellgramites. ^^ ^ ^^ 
 
 around the electric lights at night. The egg deposits 
 form conspicuous white spots the size of a nickel on 
 
 FIG. 136. The dobson, natural size. 
 
NEUROPTEEA, EPHEMER1DA, AND ODONATA 117 
 
 the lower sides of logs, rocks, and trees overhanging 
 the water, where they may be found during June 
 and July. The young drop into the water, and during 
 the larval stage of 
 nearly three years feed 
 on aquatic insects. 
 Respiration is^ accom- 
 plished by the several 
 pairs of tufts on either 
 side of the abdomen. 
 
 Other well-known 
 members of this order 
 are the ant-lion and the 
 aphis-lions or lace-wing 
 flies. The larvae of 
 these as the names suggest feed upon ants and plant lice, 
 
 FlG * 137 - Pu P a of 
 
 bellgramite, natural 
 
 FIG. 138. Hellgramite, natural size. 
 
 and may be found in places frequented by their prey in 
 June and July. 
 
 The May Flies (Ephemerida) . The members of this 
 order are distinguished by their short antennae, large front 
 wings and small hind ones, and two or three slender fila- 
 
118 ARTHROPOD A 
 
 ments at the end of the abdomen. The larvae of all the 
 species live in the water, feed upon vegetable matter, and 
 breathe by means of gill tufts. The larval life lasts from 
 one to three years during which large numbers are eaten 
 by fish. Metamorphosis to the adult form takes place in 
 May and June when the adults sometimes become so numer- 
 ous along the watercourses that the dead may be picked up 
 by the handfuls where the waves wash them up on the 
 
 FIG. 139. May fly, twice natural size. 
 
 shore. The pupa or nymph is active and much like the 
 larva in form, except wing pads are present. 
 
 The adults take no food as the mouth parts are atrophied 
 and the alimentary canal is not fitted for digestion. They 
 usually live only a day or two. 
 
 Dragon Flies (Odonata). All the numerous species of 
 this order have a similar life history which is easily studied 
 in any one of our dozen common kinds. The nymph or 
 larval stage may be found almost any time of the year in 
 mud at the bottom of ponds, and if large specimens are 
 removed to the aquarium in May and fed daily with fresh 
 
NEUKOPTERA, EPHEMERIDA, AND ODONATA 119 
 
 beef, mosquito larvse, or bits of earth worm they will be 
 seen to molt. In some cases the nymph (pupa) will climb 
 a stick or stem of a water plant during a night in June, and 
 early the following morning from a sli t in the skin of its 
 back the adult insect will come forth. In midsummer 
 
 FIG. 140. Dragon fly and larva (Plathemis lydia). Photograph natural size. 
 
 the eggs are laid on the surface of the water or on some 
 object beneath the surface. 
 
 Most dragon flies alight with expanded wings, but a 
 group of the more slender-bodied ones resting with wings 
 folded goes under the name of damsel flies. So far as known 
 all dragon flies, otherwise called devil's darning needles, 
 snake feeders, and snake doctors, are harmless and bene- 
 ficial insects. The larvae feed on mosquito larvae and other 
 aquatic forms, while the mature insect consumes large 
 numbers of mosquitoes. To note one's appetite hold it by 
 
120 
 
 ARTHROPODA 
 
 FIG . 141. Photograph of a damsel fly just out of the pupal skin below. Natural size. 
 
 the wings pressed together over its back and feed it house 
 flies of which it will devour as many as two dozen hi a few 
 minutes. 
 
 Characteristic Features of Insects 
 
 The insects agree in having a segmented body composed 
 of three clearly defined parts, the head, thorax, and abdo- 
 men. The head bears two hairlike processes, the antenna?, 
 a pair of large compound eyes, and several ocelli or simple 
 eyes. The wings varying in number from none to two 
 pairs are attached to the thorax and present nervures or 
 veins. These are air tubes or tracheae. The legs, of which 
 
NEUROPTERA, EPHEMERIDA, AND ODONATA 121 
 
 FIG. 142. Photograph of a model to show the structure of the honey bee; a, 
 salivary gland ; b, brain ; e, esophagus ; h, honey stomach ; hr, heart with five 
 cross slits through which the blood enters ; t, tongue ; m, mandible ; mx, max- 
 illa ; n, one of the eight ventral ganglia made of nerve cells and connected by 
 white nerve cords ; p, poison gland ; r, rectum or end-portion of the intestine ; 
 rt, aorta or mainblood vessel ; s, true stomach ; st, sting ; t, intestine surrounded 
 by white tubes, the kidneys ; u, ventral head ganglion. 
 
 there are never more than three pairs, are joined to the 
 thorax. All insects having a complete metamorphosis 
 pass through four stages in their life history known as the 
 egg, larva, pupa, and imago. Some forms, such as the 
 Orthoptera, Hemiptera and Odonata, are said to exhibit 
 an incomplete metamorphosis because the difference in 
 form between the larva and pupa is not very marked. The 
 young of these orders is therefore often called a nymph. 
 The larval form of the Lepidoptera is named a caterpillar , 
 
122 ARTHKOPODA 
 
 that of the Coleoptera, a grub; that of the Diptera, a 
 maggot. The larva of some families has as many as six- 
 teen legs, while in others there are from six to twelve, and 
 in the weevils no legs are present. 
 
 As the structure of the various insects is so similar, a 
 
 FIG. 143. Diagrammatic cross section of a grasshopper enlarged three times ; h, 
 chief blood vessel ; i, intestine ; , ganglion of the nerve cord ; t, stigmata or 
 spiracle for the admission of air to the branched tracheal tubes ; w, wings ; a, 
 coxa ; ft, trochanter ; c, femur ; d, tibia ; e, tarsus. 
 
 study of any form will serve to give a general knowledge 
 of the anatomy of all. Large locusts or grasshoppers are 
 easily secured, and can be dissected to advantage if pre- 
 served in seventy per cent alcohol (commercial alcohol 
 three parts and water one part). To dissect, place in a pan 
 with water sufficient to cover and fix to the wax-covered 
 
NEUROPTERA, EPHEMERIDA, AND ODONATA 123 
 
 bottom with two pins, the one passing very obliquely 
 through the head and the other through the hind part of 
 the abdomen. Cut away with scissors the dorsal portion 
 of the body wall and immediately beneath it note a light- 
 colored threadlike tube, which is the heart. Ramifying 
 among the muscles are the trachea appearing as minute 
 slender white tubes, which examined in a drop of water 
 under the microscope show spiral thickenings. If near 
 egg-laying time the female will have much of her ab- 
 domen filled with the two ovaries containing many eggs. 
 Two small tubes, the oviducts, pass from the ovaries to 
 the posterior ventral side of the abdomen, where they 
 unite. 
 
 The digestive canal is a tube extending in an al- 
 most straight course from the mouth to the posterior 
 end of the body. The much enlarged portion in the 
 thorax is the crop which receives the food from the 
 esophagus opening from the mouth. The stomach lies 
 next to the crop and leads into the intestine. Several 
 blind pouches, called ca&ca, project forward from the 
 stomach. 
 
 The nervous system is not easy to observe, but if all the 
 other organs are removed from the body, a white mass of 
 nerve matter, a ganglion, about the size of a pinhead may 
 be found on the floor of the thorax and from it two nerve 
 cords extending forward to the mouth where they pass 
 around the esophagus to a large ganglion, named the brain. 
 Two cords also pass backward from the thoracic ganglion 
 through the abdomen and bear several ganglia. All ganglia 
 are collections of nerve cells, whose processes, the fibers, 
 form the cords. 
 
124 ARTHROPODA 
 
 Importance of Studying the Insects 
 
 The necessity of investigating the habits and structure 
 of insects in order that we may be able to control them is 
 well presented in the following abstracts taken from the 
 writings of Slingerland: 
 
 A very conservative estimate puts the yearly loss from 
 insect depredations in the United States at one tenth of all 
 the farm crops, and this amounts to the enormous sum of 
 $300,000,000, and this is only about $52 for each farm. A 
 recent estimate by experts put the yearly loss from forest 
 insect depredations at not less than $100,000,000. The 
 common schools of the country cost in 1902 the sum of 
 $235,000,000, and all higher institutions of learning cost 
 less than $50,000,000, making the total cost of education 
 in the United States considerably less than the farmers 
 lost from insect ravages. 
 
 Furthermore, the yearly losses from insect ravages aggre- 
 gate nearly twice as much as it costs to maintain our army 
 and navy; more than twice the loss by fire; twice the capital 
 invested in manufacturing agricultural implements; and 
 nearly three times the estimated value of the products of 
 all the fruit orchards, vineyards, and small fruit farms in 
 the country. 
 
 We dare not hazard a guess and have no data on which 
 to base an estimate as to how much American farmers are 
 now spending in time and money in the warfare against 
 their insect enemies. It would surely aggregate a sum 
 that would startle us. But at least one hundred and twenty- 
 five entomological workers are now devoting most of their 
 energies and spending probably $250,000 in the United 
 
ARACHNIDA AND MYEIAPODA 125 
 
 States in studying injurious insects and devising methods 
 for preventing such enormous losses to American farmers. 
 Massachusetts spent more than a million dollars in trying 
 to exterminate the gypsy moth, and Congress has just 
 appropriated $250,000 to fight the boll-weevil and other 
 troubles in southern cotton fields. Farmers are trying to 
 feed to insects over two thousand tons of Paris green 
 annually in the United States. 
 
 The statistics for New York state also offer some inter- 
 esting comparisons along this line. The total value of all 
 farm and forest crops, excluding animal products, in New 
 York, in 1899, was $150,000,000, and the one tenth that the 
 insects got was worth $15,000,000. It may seem incredible 
 that it costs such a sum to feed New York's injurious 
 insects every year, but it is an average of only $66 for each 
 of the 227,000 farms in the state; and there are few farms 
 where the crops are not lessened more than this amount 
 by insects. It is admitted that the codling moth alone 
 ruins $3,000,000 worth of apples and pears yearly in the 
 state, and in 1901 the Hessian fly took half of New York's 
 wheat crop, thus robbing the farmers of $3,500,000. 
 
 8. ARACHNIDA AND MYRIAPODA 
 
 The Arachnida, including the spiders, scorpions, and 
 mites, are distinguished from other arthropods by the pres- 
 ence of four pairs of legs, the division of the body into two 
 parts, called cephalo-thorax and abdomen, and the absence 
 of antennae. From two to six pairs of eyes are just visible 
 on the upper part of the forehead. No ears have been 
 
126 ARTHROPODA 
 
 found, and as none of the group make any noise they prob- 
 ably can not hear. 
 
 The first pair of mouth appendages are the chelicerce, 
 terminating in claws at whose ends poison glands open. 
 The idea that thp bite of a spider which is made by the 
 chelicerse is dangerous, has no foundation in fact. In most 
 of our common species the terminal claw is scarcely long 
 enough to reach through the skin, and the poison is not 
 sufficient to cause any discomfort. Occasionally dirt 
 
 FlG. 144. Agalena, the grass spider. At the right is a photograph of its webs as 
 seen on a dewy morning ; at the left the spider with its cocoon of eggs in the 
 overlapped leaf photographed natural size. 
 
 getting access beneath the skin with the poison may cause 
 an inflammation. The large spiders of the South, the taran- 
 tulas, possess large fangs and enough poison to make their 
 victim quite sick. 
 
 The second pair of mouth parts, looking like legs, are the 
 pedipalps. On the ventral side of the abdomen near its 
 stalk attachment to the cephalo-thorax may be seen a pair 
 or two of slits opening into the lung sacs. These consist 
 of small cavities across which hang about a dozen lamellse 
 
ARACHNID A AND MYRIAPODA 127 
 
 FIG. 145. Lycosa on its back ; p, poison fang ; s, spinneret. Photograph nat- 
 ural size. 
 
 FJG, 146. Lycosa with its cocoon of eggs. Photograph natural s 
 
128 
 
 ABTHROPODA 
 
 or plates of tissue, in which the blood circulates to give 
 off its carbon dioxide and take up oxygen necessary for 
 the life of every part of the body. 
 
 The spiders are divided into two groups, the spinners, 
 or sedentary spiders, and 
 the non-spinners, or wander- 
 ing spiders. Of the spinners 
 there are four kinds. 
 
 The tunnel weavers are 
 those which make tubes in 
 the earth and line them 
 with silk. Some such as the 
 trapdoor spiders of Texas 
 and California have suffi- 
 cient skill to make a door to 
 close the entrance against 
 intruders. 
 
 The tube weavers make 
 the webs so conspicuous 
 in the grass on a dewy 
 morning. At one side of 
 the web a tube extends 
 toward the ground. Some 
 of these species spin quite 
 deserted buildings and in 
 
 FIG. 147. Photograph of the nest of a 
 Texas trapdoor spider with the door 
 open to the left. 
 
 Of 
 
 dense webs in corners 
 bushes. 
 
 The line weavers are those which construct irregular 
 webs known as cobwebs. 
 
 The orb weavers work with mathematical precision, spin- 
 ning spirals supported by numerous radii. The male orb- 
 weaving spider is much smaller than the female which 
 
ARACHNIDA AND MYRIAPODA 129 
 
 sometimes becomes so angered with her mate as to kill 
 and eat him. 
 
 The silk with which spiders work is formed by glands 
 in the abdomen, which open by two or three pairs of promi- 
 nences, the spinnerets at the posterior part of the abdomen. 
 The excretion passing out of these several orifices unites 
 
 Fia. 148. Epeira, the common garden spider on its web. Photograph one half 
 natural size by Charles Morris. 
 
 to form a single thread. The chief use of spiders' silk is 
 for cross hairs in telescopes. 
 
 The wandering spiders never spin complete webs, but 
 wander about buildings and fields. Our common species 
 are rather large, and the female carries with her the small, 
 round cocoon containing the eggs or young. Most spiders 
 deposit their eggs, often numbering nearly a hundred, in 
 cocoons, where they hatch in about two weeks, and the 
 stronger young prey on the weaker for several days, so 
 
130 
 
 ARTHROPODA 
 
 that not more than a dozen individuals survive. In 
 some species the young pass the winter in the cocoon. 
 
 FlG. 149. Argiope, the large orb weaver just completing the spinning of the wind- 
 ing stair. Photograph two thirds natural size. 
 
 The harvestmen or grandady-long-legs are beneficial mem- 
 bers of this group as they feed largely on harmful insects. 
 
ARACHNIDA AND MYRIAPODA 
 
 131 
 
 The itch mite (Sar copies scabei), causing the itch in man, 
 and Demodex folliculorum, the parasite sometimes present 
 
 FIG. 150. Demodex folliculorum enlarged one thousand 
 times. After Selenka. 
 
 in the human hair follicles, are Arachnida much changed 
 on account of their parasitic habits. The minute jigger 
 
 FIG. 151. Scorpion showing the sting at the posterior end. Photograph natural 
 size. 
 
 or chigger, so numerous in old berry patches in the South- 
 ern and Central States, often causes great inconvenience 
 by burying itself beneath the human skin. 
 
132 
 
 ARTHROPODA 
 
 The scorpions, usually with an elongated abdomen at the 
 end of which is a sting and the opening of a poison gland, 
 dwell in the warmer parts of our country and other tropical 
 regions. 
 
 Myriapoda 
 
 The members of this class are characterized by an 
 elongated body consisting of only two regions, the head 
 
 FIG. 152. Scutigera forceps, a harmless centiped. Natural size. After Marlatt. 
 
 and trunk. The latter bears one or two pairs of jointed 
 feet on each segment. They are divided into two groups, 
 
 FIG. 153. A poisonous centiped from Texas. Half natural size. 
 
 one of which, the centipeds, includes those forms having 
 a single pair of legs to each body segment, while the other ? 
 the millepeds, have two pairs of legs to each segment. 
 
CRUSTACEA 130 
 
 Scutigera forceps is a common centiped seen running 
 about in dark cellars or basements. It is entirely harmless. 
 Other harmless centipeds are found under logs and stones. 
 Scokpendra is the genus of the poisonous centipeds of 
 the South, the West Indies, and South America. They 
 are from six to ten inches long, and with their poison fangs 
 are capable of inflict- 
 ing serious bites on 
 man. 
 
 The galley worm 
 (Spirobolus), a com- 
 mon species of mille- Fm 154< _ Galley worm . 
 
 ped, lives under 
 
 stones and logs where it feeds on dead snails and earth- 
 worms. Polydesmus is a flat milleped found in moist 
 places. 
 
 9. CRUSTACEA 
 
 The crustaceans differ from the other arthropods in 
 usually breathing by gills and having two pairs of antenna. 
 Many forms possess a hard outer skin or exoskeleton to 
 which the name of the class is due. The fresh water cray- 
 fish (Cambarus) and the lobster (Homarus) are so similar 
 in structure that a description of one applies almost equally 
 well to the other. 
 
 The body of the crayfish, bearing nineteen pairs of appen- 
 dages, is divided into a cephalothorax and abdomen. The 
 former, including the head and thorax, is covered by a cal- 
 careous shield, the carapace, which when broken off on the 
 sides reveals the gills composed of feathery filaments with 
 
134 
 
 ARTHROPODA 
 
 FIG. 155. Crayfish or crawfish (Cambarus bartoni). Photograph natural size. The 
 antennae are the two long backward projections from the head and the auten- 
 nules the short forward projections. 
 
 FIG. 156. Crayfish with the left half of the body structures removed ; a, intestine ; 
 6, ventral artery ; c, brain ; e, heart ; et, gastric teeth ; i, oviduct ; /, liver ; m, 
 muscles ; n, green gland (kidney) ; o, ovary ; p, pyloric stomach; r, nerve cords ; 
 s, cardiac stomach ; st, mouth ; u, telson ; w t openings of veins into the pericar- 
 dial sinus. Twice natural size. 
 
 the bases of the main stems attached below. A median 
 spine, the rostrum, projects between the eyestalks support- 
 ing the compound eyes on movable stalks, beneath which 
 
CRUSTACEA 135 
 
 are the antennules about one fourth as long as the jointed 
 antenna? proper. On the lower surface of the basal joint 
 of each of these is the opening of the green glands or 
 kidneys. On the thorax are four pairs of long slender 
 walking legs, in front of which is a pair of very large legs 
 called chelipeds, terminating in pincers, the chelce. Anterior 
 to these are three pairs of small appendages, the maxillipeds, 
 or jaw feet, of use in feeding. 
 
 The head proper shows in the mouth region a pair of 
 hard notched lateral moving mandibles and behind them 
 two pairs of leaflike maxillce. The second pair of maxillae 
 differs from the first pair in having a flat paddle-like 
 process, called gill bailer, used to bring the water forward 
 from the gill chamber, in which are the gills beneath the 
 carapace. On the ventral side of several segments of 
 the abdomen are small appendages, termed pleopods or 
 swimmerets, which carry the eggs in the female. Each 
 pleopod consists of a basal piece, the protopodite, and two 
 branches, the outer of which is the exopodite and the inner 
 the endopodite. This is the typical structure of a crusta- 
 cean appendage, but in many cases it is much modified 
 by use, as in the walking legs where the exopodite is 
 wanting. 
 
 By pinning down the specimen in a waxed-bottom pan 
 full of water and cutting off the carapace and dorsal por- 
 tion of the abdomen, some of the structures shown in the 
 figure may be found. The male can be distinguished from 
 the female by the presence of the minute orifice of the 
 reproductive organ on the ventral side of the last leg near 
 its junction with the thorax. In the female the opening is 
 on the third leg from the last. 
 
136 ARTHROPODA 
 
 The blood of the crayfish, like that of the insects, is color- 
 less. After circulating through the arteries and their 
 branches to carry oxygen and nourishment to all parts of 
 the body it collects in irregular channels, called sinuses, 
 lying between the muscles and the other organs. From 
 the sinuses, vessels lead the blood to the gills on either side 
 beneath the carapace to absorb oxygen from the surround- 
 ing water and give off the carbon dioxide collected from 
 the tissues of the body. From the gills the blood returns 
 
 FJG. 157. Photograph of the lobster one third natural size. 
 
 to the pericardial sinus and enters the heart through six 
 slits with valves opening inward. 
 
 The lobster (Homarus americanus') ranges along the 
 Atlantic coast from Labrador to Delaware Bay. Of late 
 years it has become so scarce that laws have been passed 
 for its protection. In Connecticut none may be caught 
 under six inches long, while in New York and Massachu- 
 setts they must be not less than ten and a half inches in 
 length. At Cold Spring Harbor, Long Island, and at 
 Woods Hole, stations have been established by the govern- 
 ment for the purpose of rearing young lobsters. The eggs, 
 
CRUSTACEA 
 
 137 
 
 numbering several thou- 
 sands, are taken from the 
 female which carries them 
 entangled among the pleo- 
 pods on the ventral side of 
 the abdomen, and hatched 
 in prepared tanks. The 
 young are thus protected 
 from the voracious appe- 
 tites Of marine fish, and FIG. 158. Hermit crab (Eupagurus 
 , - -. -, . ,. longicarpus). Natural size. 
 
 when old enough to care for 
 
 themselves are distributed at favorable points along the 
 
 coast. 
 
 A molting process takes place among the crustaceans 
 
 FIG. 159. Fiddler crabs (Gelasimus minax). Note the large fighting cbela on the 
 two specimens at the right. On specimen at left it was broken off and is just 
 being renewed. Photograph natural size by Overton. 
 
138 
 
 AKTHROPODA 
 
 similar to that occurring in the larviB of insects. The hard 
 covering becomes too small for the growing animal, and 
 
 in the lobster it ^ 
 
 splits along the 
 median dorsal line, 
 while the blood 
 leaves the limbs, 
 permitting them 
 to be withdrawn 
 from their case- 
 ments. The lining 
 of the whole ali- 
 mentary canal is 
 also shed. The 
 animal just before 
 molting is known 
 as the black lobster. 
 The newly molted 
 crab is marketed 
 under the name of 
 soft-shelled crab. 
 
 The hermit crabs 
 protect themselves 
 by living in the 
 abandoned shells 
 of some mollusks, 
 and when the in- 
 creased size of the 
 body makes the shell too small, the animal seeks a 
 larger one. Of the edible crabs, the commonest are the 
 large blue crab (Callinectes hastatus), and the oyster 
 
 FIG. 160. Photograph of Cyclops enlarged forty 
 times. An egg mass at the right. 
 
CRUSTACEA 
 
 139 
 
 crab. (Pinnotheres ostreum) the female of which lives in 
 oysters. 
 
 The water fleas just visible to the naked eye are present 
 in nearly all waters and 
 become very abundant 
 in stagnant water. The 
 common fresh water gen- 
 era are Cypris, Daph- 
 nia, and Cyclops. They 
 make up a large part 
 of the food for young fish. Many species of small crus- 
 taceans are parasites on fish or other aquatic animals, 
 and because of their habits become so changed in ap- 
 
 Fm. 161. Daphnia enlarged forty times. 
 
 FIG 1G2. Acorn-shell barnacles on a sand dollar. 
 
140 
 
 ARTHROPODA 
 
 pearance as to lack all features characteristic of the 
 class. 
 
 The barnades found only in salt water show how organs 
 
 originally intended for 
 one purpose may be 
 adapted to another. The 
 acorn-shell barnacle (Bal- 
 anus balanoides) lives in 
 calcareous shells at- 
 tached to the bottoms 
 of ships, wharves, or 
 other objects in the 
 water. The legs no longer 
 needed for locomotion, 
 as in its ancestors, are 
 extended through the 
 open shell to secure food. 
 On account of disuse the 
 eyes have been lost. 
 The goose barnacle (Lepas 
 
 anatifera) is often found attached to floating objects by 
 a stem two or three inches in length. Between the two 
 pairs of calcareous plates 
 protecting the body are 
 thrust appendages, form- 
 erly used as legs, to 
 catch food. 
 
 The terrestrial crusta- 
 ceans number but a few 
 species. The common 
 ones known as pill bugs, 
 
 FIG. 163. Goose barnacles with tb e right shell 
 removed from the one on the left. Natural 
 
 FIG. 164. Sow bug (Oniscus asellus). After 
 Paulmier. 
 
CliUSTACEA 141 
 
 sow bugs, or wood lice abound everywhere under logs and 
 stones during most of the year. They are about a half 
 inch long and have a convex grayish dorsal surface. They 
 feed on decaying vegetable matter. Respiration is effected 
 by gills instead of by lungs or trachea characteristic of 
 most land forms. The inner terminal divisions of the 
 abdominal legs, which are covered and kept moist by the 
 outer division, are the gills. 
 
 Crustaceans are remarkable for their perfect adaptation 
 to widely different 
 conditions of life. 
 They dwell in fresh 
 water, in the sea, 
 on land, and as 
 parasites. In the 
 Mammoth Cave of 
 Kentucky are blind 
 
 FIG. 165. Photograph of the shrimp. Natural size. 
 
 crayfish which 
 
 show by certain features that they are undoubtedly de- 
 scended from the forms outside of the cave enjoying perfect 
 sight. Some species live in the ocean at a depth of nearly 
 four miles. While most crustaceans are solitary, some 
 like the shrimp much used for food occur in vast shoals in 
 the ocean. 
 
PART II 
 
 THE ANARTHROPODA : INVERTEBRATES 
 WITHOUT JOINTED LEGS 
 
 10. MOLLUSCA 
 
 THE members of this phylum differ from the preceding 
 in not having segmented bodies or jointed feet. Most of 
 the twenty thousand species are included in the three 
 important classes, Pelecypoda, Gastropoda, and Cepha- 
 lopoda. 
 
 Pelecypoda: Bivalved Shellfish 
 
 The name bivalve is derived from the two shells which 
 hinged together form the protecting case for the soft- 
 bodied animal within. All bivalves are aquatic. Certain 
 species form a leading item of food in many parts of the 
 world. 
 
 The soft-shelled clam (My a arenaria), abundant north of 
 Cape Cod, occurs in large numbers in the mud flats, from 
 which they are dug at low tide. They usually lie in the 
 mud at a depth of from two inches to a foot, and have a 
 very long siphon consisting of two tubes, of which the 
 ventral one is used for taking in water and food, while the 
 excretory products pass out through the dorsal one. 
 
 The hard-shelled clam (Venus mercenaria), or quahog, is 
 the common edible species south of Cape Cod. 
 
 142 
 
MOLLUSCA 
 
 143 
 
 The fresh water clams, Anodonta and Unio, often called 
 mussels, are present in large numbers in some fresh water 
 streams and lakes. The shell of the Unio is smaller and 
 thinner than that of Anodonta. The sexes are separate, 
 but the male re- 
 sembles the female 
 so closely that a 
 microscopic exam- 
 ination of the re- 
 productive glands 
 is necessary to dis- 
 tinguish one from 
 
 the Other. FIG. 16o. Sof t-shelled clam with a piece cut out of 
 
 The ejrprs of clams the end of the sipllon to snow botl1 tubes. Photo- 
 
 graph natural size. 
 
 are hatched within 
 
 the shell of the mother, and in a few months the young 
 pass out into the water and attach themselves to fishes 
 by a pair of sharp projections 
 on the ventral margins of the 
 shell. Here they lead a para- 
 sitic life, absorbing juices from 
 the body of the fish for some 
 weeks and pass through a 
 metamorphosis, after which 
 they drop to the bottom and 
 feed on small crustaceans and 
 other aquatic organisms. Most 
 clams move about from time 
 to time by means of a single ventral projection, the foot, 
 which is protruded between the open valves. 
 The oyster (Ostrea virginiana), so highly prized for food, 
 
 FIG. 167. Hard-shelled clam. 
 Photograph half natural size. 
 
144 
 
 ANARTHROPODA 
 
 FIG. 168. Oyster of t 
 (Ostrea virginiana). 
 half natural size. 
 
 Photograph one 
 
 differs from the clams in having no siphon and a foot so 
 rudimentary as to be unable to move. The oystermen are 
 therefore accustomed to plant the young in shallow water 
 where they remain three or four years to mature. Our 
 
 Atlantic coast furnishes 
 twenty-five millions of dol- 
 lars' worth of oysters an- 
 nually. The Japan oysters 
 are the largest, some species 
 attaining a length of three 
 feet. 
 
 The pearl oysters (Melea- 
 grina), along the Persian 
 
 Q u j and coagts Q f C ey l ol ^ 
 
 are the source of most 
 pearls, but some pearls have been found in the fresh water 
 clams and oysters of our own country. Pearls are depos- 
 its of nacre formed around foreign bodies by the mantle, 
 and are of the 
 same composition 
 as the inner lining 
 of the shell so 
 much valued as 
 the mother of 
 pearl. The ship- 
 worm (Teredo 
 navalis) is a pecu- 
 liar bivalve, causing much damage by boring into ships 
 and piles supporting the wharves along the ocean. 
 
 Anatomy of the Fresh Water Mussel. Any clam may 
 be used for dissection, but the following description applies 
 
 FIG. 169. Photograph of the shipworm slightly en- 
 larged. 
 
MOLLUSCA 
 
 145 
 
 particularly to the fresh water mussel. A horny or elastic 
 ligament unites the two valves on the dorsal aspect and 
 tends to open the shell along the ventral margin. The 
 concentric parallel ridges on the outside of the shell repre- 
 sent successive additions of lime and are called lines of 
 growth. The eleva- 
 tion near the hinge 
 is the wnbo. To 
 open the shell place 
 it in boiling water 
 a minute or two and 
 then slip the knife 
 between the two 
 slightly open valves 
 and loosen the ad- 
 ductor muscles from 
 one side of the shell. 
 The line within 
 the valve concentric 
 with the ventral 
 margin and connect- 
 ing the two muscle 
 scars is the pallial line along which a membrane, the 
 mantle, is attached. The two mantles covering the body of 
 the mussel are almost as large as the valves to which they 
 adhere closely. By removing the left mantle and immers- 
 ing the specimen in a pan of water the relations of the soft 
 parts may be made out. The firm conical mass projecting 
 ventral and anteriorly is the foot. The gills are the two 
 thin membranes on either side of the body just within the 
 mantle. They are covered with ciliated cells, whose pur- 
 
 FIG. 170. Wood injured by the ship worm. 
 
146 
 
 ANARTHROPODA 
 
 FIG. 171. A freshwater mussel with the right valve mantle and gills and some 
 tissue at the base of the foot removed ; a, anterior adductor muscle ; au, auricle 
 of the heart ; ft, foot ; g, reproductive gland ; gl, gill ; i, intestine ; k, kidney ; 
 m, mantle ; n, nerve ganglia connected by nerve cords o ; p, posterior adductor ; 
 pi, labial palps ; si, siphon ; v, ventricle. The dark lines on the mantle and 
 foot are blood vessels. 
 
 pose it is to cause the water to flow in and out through 
 the siphons, thereby bringing in food and oxygen. By 
 detaching a minute portion of the gill of a live mussel 
 and mounting it in a drop of water on a glass slip and 
 examining with the microscope the cilia (hairlike pro- 
 cesses) may be seen in motion. 
 
 The heart, consisting of two auricles and a ventricle, is 
 seen by removing the dorsal portion of the mantle. In a 
 live mussel opened, the heart can be noticed beating, as 
 the milky blood passes from the auricles to the ventricle 
 and thence through the pedal artery to the foot and body. 
 It then goes to the gills where carbon dioxide is given off 
 and oxygen received before it is returned to the heart. 
 
MOLLUSCA 147 
 
 The digestive system is well defined. Near the anterior 
 adductor muscle between the two pairs of triangular flaps, 
 called labial palps, :'s the mouth opening into a short esopha- 
 gus leading into the stomach surrounded by a dark tender 
 mass of tissue, the liver, from which ducts empty into the 
 stomach. The intestine after leaving the stomach makes 
 a turn on itself in addition to several bends, and terminates 
 dorsal of the posterior adductor muscle in the exhalant 
 siphon. 
 
 The nervous system is difficult to demonstrate. It con- 
 sists of three pairs of ganglia or bunches of nerve cells 
 connected by nerve cords. The visceral ganglia he on the 
 under side of the posterior adductor muscle. From these 
 a pair of threadlike nerves extend forward to the cerebral 
 ganglia at the base of the labial palps and behind the an- 
 terior adductor muscle. A circular nerve cord joining 
 these two ganglia surrounds the mouth and from each a 
 nerve cord leads to the pedal ganglion near the center of 
 the foot. 
 
 Gastropoda: Snails and Slugs 
 
 The univalve mollusks are unsymmetrical and have but 
 one shell which is often in the form of a spiral. The pond 
 snail (Limnea), abundant in ditches and stagnant ponds, 
 has a right-handed shell, i.e., starting from the apex the 
 coil turns toward the right. Physa, the other pond snail, 
 has a left-handed shell. The eggs of pond snails appear as 
 minute white spots in a mass of transparent albumen. 
 During the summer months they are easily found adhering 
 to boards, stones, and other objects in the quiet waters. 
 
148 
 
 ANARTHROPODA 
 
 FIG. 173. Forest snail show- 
 ing the two tentacles with 
 an eye on the end of each. 
 Photograph from life. 
 
 FIG. 172. Pond snail and two of its egg 
 masses. The one on the right is entirely 
 withdrawn in its shell. Photograph from 
 life natural size. 
 
 FIG. 174. Photograph of the big slug one half natural size. 
 
MOLLUSCA 
 
 149 
 
 Examination of the young while still in the egg mass will 
 show the beating of the heart. 
 
 Planorbis, another aquatic snail, is distinguished by 
 having all its whorls in the same plane. The forest snail 
 (Helix alboldbris) and the big slug (Limax maximus) are 
 terrestrial. The slugs are characterized by the absence 
 of an external shell and in its stead a plate-like shell buried 
 in the mantle on the back. Slugs and snails breathe by 
 means of lungs, the opening to which is a round hole at 
 the edge of the mantle. Slugs are destructive to garden 
 plants, a common offender being the 
 small dark brown one hiding by day 
 under boards arid logs. 
 
 Cephalopoda: Squids, Cuttlefish, etc. 
 
 The members of this class are so 
 named because a portion of the foot is 
 fused with the head. Around the mouth 
 are several tentacles or arms provided 
 with suckers, serving as powerful organs 
 in seizing prey. In the common squid 
 (Loligo pealii), the lower portion of the 
 foot forms a tube through which the 
 water contained in the mantle cavity 
 may be violently expelled and the ani- 
 mal thus propelled through the water. 
 Into this funnel opens the duct of the. 
 ink sac by which the squid and cuttlefish color the water 
 in order to escape from their enemies. The sense of sight 
 is well developed in the cephalopods, a large eye being 
 
 FIG. 175. The squid. 
 One fourth, natural 
 size. 
 
150 ANARTHROPODA 
 
 located on either side of the head. In the squids and cuttle- 
 fish the shell is rudimentary and is buried within the 
 mantle, while in the pearly nautilus (Nautilus pompilius) 
 it is in the form of a spiral divided into chambers, the larg- 
 est and outer of which is alone occupied by the animal. 
 As soon as the body becomes 
 too small for one chamber it 
 moves forward, constructing a 
 partition behind it. This is the 
 creature which inspired the cele- 
 brated poem, "The Chambered 
 Nautilus," by Holmes. 
 
 The cephalopods are of little 
 economic importance. The cut- 
 . 176. -Pearly nautilus th tlefish supply sepia for the artist 
 
 half the shell removed. 
 
 and are of some use for food. 
 Squid are used for cod bait along the New England shore. 
 
 ii. VERMES 
 
 The worms form a group of animals not easily defined 
 because of their great variation in structure and habits; 
 therefore, modern zoologists have separated them into sev- 
 eral subkingdoms, of which the three most important are 
 Annulata, Nemathelminthes, and Platyhelminthes. 
 
 Annulata or Segmented Worms 
 
 This phylum is widely represented by leeches and earth- 
 worms. As the habits of the two groups are quite different, 
 each will be described separately. 
 
 Leeches. These are often called bloodsuckers, owing to 
 
VEEMES 151 
 
 their habit of fastening themselves to the skin of man 
 or any of the lower animals and sucking their blood. They 
 are Usually found in moist places only, often being aquatic. 
 
 FIG. 177. Photograph of the medicinal leech. Natural size. 
 
 The medicinal leech (Hirudo medicinalis) was used fifty 
 years ago for blood-letting when the fallacious idea pre- 
 
 Fi. 178. The large water leech just after a full meal. Ventral view showing both 
 suckers, head at the left. Photograph natural size. 
 
 vailed that people could be cured of sickness by letting 
 out the bad blood. After the leech fastens itself to the 
 skin by its suckers the toothed jaws quickly rasp a hole 
 
152 ANARTHROPODA 
 
 through to the superficial blood vessels and in an hour the 
 hungry creature will be distended to triple its former size. 
 The alimentary canal has several pouches along either side 
 to increase its capacity. A full meal lasts the animal one 
 year. 
 
 Tn some parts of the tropics such as India and Ceylon, 
 there are land leeches about an inch long in the meadows 
 and woods capable of scenting their prey at some distance, 
 
 FIG. 179. Night walker ; c, clitellum ; TO, mouth ; n, opening of reproductive glands. 
 Photograph natural size. 
 
 and are quick in their movements, so that a person brushing 
 through the jungle often becomes covered with them. The 
 largest leech is an American species, Macrobdella valdiviana, 
 which attains a length of more than two feet. 
 
 Earthworms. These are often called rain worms or 
 angleworms. There are a dozen or more species in tliis 
 country, but for study the night walker (Lumbricus agri- 
 cola) is best on account of its large size. It may be recog- 
 nized by its flattened posterior end. It lives in rich garden 
 soil and near manure piles. In dry weather the holes may 
 extend to a depth of six feet. Specimens may often be 
 
VERMES 153 
 
 caught by seeking them with a lantern at night when they 
 roam about. They can easily be kept for months in a box 
 of rich earth occasionally moistened and supplied with 
 decaying leaves. A wire netting should be tacked over the 
 top. In order to kill them properly for dissection, they 
 should be placed in a jar or dish a foot in diameter and cov- 
 ered with water to which thirty cubic centimeters (one 
 ounce) of alcohol is to be added every forty or fifty minutes 
 
 FlG. 180. Forepart of an earthworm with the left body-wall removed ; a, dorsal 
 blood vessel; 6, brain ; c, crop ; d, opening of the male reproductive organs ; 
 g, gizzard ; i, intestine ; k, kidney ; m, mouth ; , one of the ganglia of the nerve 
 cord ; oe, esophagus ; p, pharynx ; r, receptacles for sperm cells ; ov, ovary ; ovd, ' 
 duct from ovary ; v, ventral blood vessel. Drawing by W. H. Reese. 
 
 until they become unconscious. They are then best pre- 
 served in seventy per cent alcohol. 
 
 Each of the segments or somites numbering about one 
 hundred and fifty bears four pairs of short bristles (setce) 
 by means of which the worm holds itself so firmly in the 
 burrow when one attempts to dislodge it. The swollen 
 band between the thirtieth and fortieth somites is the 
 clitellum, from which exudes a sticky substance used to 
 construct the egg band. This encircling band after being 
 hardened by the air is worked forward and as it passes the 
 fourteenth or fifteenth segments receives the eggs there 
 extruded by two minute apertures not visible to the naked 
 
154 ANARTHROPODA 
 
 eye. Between the ninth and eleventh somites are two 
 pairs of openings from which sperm cells enter the band 
 and render the several eggs fertile. As the band slips off 
 the head it is changed into a closed capsule within which 
 only one worm develops, the others being devoured by 
 the sole survivor. 
 
 For dissection, a worm over five inches long should be 
 pinned ventral side down in a pan of water and a slit made 
 with the scissors through the body wall in the anterior 
 half along the mid-dorsal line. Pin down the body walls 
 on either side and note the parts as shown in the figure. 
 The blood runs forward in the dorsal vessel and backward 
 in the ventral one. No true heart is present, but the five 
 pairs of aortic arches are contractile. The paired nephridia 
 in each somite are the kidneys, which conduct the waste 
 matter outside of the body. The worm has no tracheal 
 tubes, gills, or lungs, but receives oxygen into the blood 
 and casts out the carbon dioxide by means of the small 
 vessels ramifying near the surface. 
 
 Earthworms feed on decayed leaves and other vegetable 
 matter. They are of much service in keeping the soil 
 loose and permitting the water and air to penetrate to the 
 roots of plants by means of their burrows. They also 
 make good food for birds. Their power of regeneration 
 after injury is remarkable. If one be cut in two near the 
 middle each half will often develop into a complete worm. 
 The power to regenerate lost parts is much greater in the 
 lower animals than in the higher ones. A tadpole may 
 regenerate a lost leg but not a half or even a fourth of its 
 body, while a mammal can not reproduce even a fourth of 
 a finger or toe removed, 
 
VEKMES 
 
 155 
 
 Nemathelminthes or Threadworms 
 
 The round worms differ from the Annulata in not show- 
 ing any external evidence of segmentation. Most of the 
 species live as parasites during part or all their lives. As- 
 caris is a genus containing several species which are often 
 present in the in- 
 testines of mam- 
 mals, and one spe- 
 cies is common in 
 the lungs of the 
 frog. Trichina, a 
 microscopic round 
 worm causing the 
 condition known 
 as measly pork, is 
 a dangerous para- 
 site to man. He 
 becomes infected 
 by eating affected 
 pork not well 
 cooked. In 1892, 
 the United States Department of Agriculture found over 
 seventeen thousand carcasses of hogs containing Trichina?. 
 A fuller discussion of parasitic worms is given in the chap- 
 ter on parasites. 
 
 The vinegar eel (Anguillula) is a free living worm often 
 present in good cider vinegar. It is just large enough to be 
 recognized by the naked eye, and if a little vial containing 
 some vinegar be looked at toward the light as many as five 
 hundred may be seen squirming vigorously. They are 
 
 FIG. 181. Ascaris lumbricoides : a parasite often 
 present in the intestine of children. Photograph, 
 natural size. 
 
156 
 
 ANARTHROPODA 
 
 FlG. 182. Three encysted Trichinae in human flesh. Photograph enlarged sixty 
 diameters. 
 
 harmless to man. A species of Anguillula is also common 
 in stagnant ponds and ditches, and may be found by ex- 
 amining under the low power of the microscope a drop 
 of water scraped from decaying wood or leaves taken from 
 foul water. 
 
 Horse-hair worms of which Gordius aquations is the most 
 common occur in streams, ponds, and watering troughs. 
 They do not originate from a horse hair, as is popularly sup- 
 posed. They are from five to ten inches long and as thick 
 as a pin. The eggs are either laid in the damp earth or 
 water. In the latter case the young socn after hatching 
 bore into the larva of some aquatic insect which is later 
 eaten by a fish. The young hair worm no larger than a 
 
VERMES 
 
 157 
 
 pin head works its 
 way through the 
 walls of the fish's 
 intestine to the 
 muscles, remains 
 several months 
 quiescent until 
 spring, when it 
 again enters the 
 i n t e s t i n e and 
 passes out into the 
 water. Its length 
 at this time is 
 about an inch. 
 
 In a few weeks it reaches full size. The young of those 
 species laying eggs in the damp earth bore into caterpillars, 
 grasshoppers, locusts, and beetles. During the months 
 of August, September, and October hair worms may some- 
 times be found in the locusts by pulling open the abdom- 
 inal cavity with forceps or needles. 
 
 FIG. 183. Horse-hair snake. Photograph twice 
 natural size. 
 
 Platyhelminthes or Flatworms 
 
 The flatworms are remarkable for their variation in 
 size. Some of them living parasitic on the gills of fish 
 and the king crab are only one or two millimeters long, 
 while the tapeworms parasitic in man reach a length of 
 fifty feet. Many members of this phylum are parasites 
 and all have soft bodies usually much flattened dorso- 
 ventrally. There is no body cavity (ccelome) surrounding 
 
158 ANARTHROPODA 
 
 the internal organs, this space being filled up with a kind 
 of connective tissue called parenchyma. 
 
 Tapeworms. These are so named because they resem- 
 ble a piece of tape. All are parasites and dwell within 
 
 FIG. 184. Human tapeworm fourteen feet in length; h t head. Photograph three 
 fourths natural size. 
 
 various species of vertebrates from fish to man. The 
 life history of Tcenia saginata, a human parasite, is typical 
 of the group. In the adult state it dwells only in the 
 intestine of man and is usually from ten to fifty feet in 
 length. Its head known as the scolex is armed with four 
 
VERMES 
 
 159 
 
 suckers enabling it to hold fast in the mucous coat of the 
 canal, while its body, called strobila, lies free in the intestine. 
 The segments of the body, narrow and short near the head, 
 increase in size posteriorly and may number as many as 
 one thousand. They are known as proglottides. It has 
 no alimentary canal and no blood system, the nourish- 
 ment being absorbed through the body wall. The nervous 
 system consists of two small ganglia in the head and a 
 nerve cord extending from them along each side of the 
 body. Each of the segments in the posterior half of the 
 adult worm contains both male and female organs of 
 reproduction and 
 each segment 
 near the end has 
 more than a thou- 
 sand mature eggs. 
 From time to 
 time a segment 
 is broken off and 
 passes to the ex- 
 terior where if 
 through water or 
 otherwise the eggs 
 within it reach 
 the alimentary 
 canal of the cow 
 further develop- 
 ment ensues. 
 
 The young migrate from the digestive tract of the cow to 
 the muscles and form a cyst or sac in which stage it is 
 known as a bladder worm or cysticercus. This is the larval 
 
 FIG. 185. A piece of pork containing several cysti- 
 cerci (larvae) of a human tapeworm (Tsenia soliurri). 
 Photograph natural size. 
 
160 
 
 ANARTHROPODA 
 
 state, and no further growth occurs until the meat is 
 eaten by man in whom the larva transforms into the 
 tape form. The poisonous excretions given off by the 
 worm cause nausea, headache, and dizziness in the host. 
 
 The larval stage of the tapeworm of the dog is found 
 in the rabbit, while the early stage of the cat's tapeworm 
 occurs in the mouse. It is therefore evident that the 
 completion of the life cycle in these parasites requires two 
 hosts. 
 
 Fresh Water Flatworms. These are common in most 
 ponds and streams. They vary in size from minute 
 
 specks to forms 
 more than a half 
 inch in length. 
 The whitish or 
 grayish color to- 
 gether with their 
 slow gliding move- 
 ments over the 
 surface of water 
 plants and the 
 under sides of stones and sticks are the features by which 
 they may be recognized. They move largely by means 
 of the cilia over the surface. A good plan for secur- 
 ing them is to place in a jar of water some sticks and 
 leaves taken from several quiet pools. The following day 
 they may be seen on the side of the vessel. In many 
 forms the mouth is in the middle of the under side and the 
 alimentary canal has a forward and two backward exten- 
 sions with numerous lateral branches. This group has the 
 power of regeneration to such a degree that if an individual 
 
 FIG. 18G. Planaria ; a common aquatic flatworm. 
 The two minute dots in the head are the eyes, and 
 the black much branched structure is the alimen- 
 tary canal. Photograph enlarged four diameters. 
 
ECHINODERMATA 161 
 
 be cut into several pieces each one will grow into a com- 
 plete worm. 
 
 The largest of the flatworms are marine and belong to 
 the group Nemertini. Some of these reach a length of 
 nearly one hundred feet. The common form found along 
 the Atlantic coast is Cerebratulus, which has a flat, cream- 
 colored body two or three feet long. It inhabits the mud 
 and sand at the water's edge where it may be dug out during 
 low tide. 
 
 The Rotifers are interesting microscopic worms present 
 in stagnant water. They belong to the subkingdom of 
 Trochelminthes. Upon the head are two circles of cilia 
 so vibrating to draw in food as to resemble the rotation 
 of a wheel. In early summer they are parthenogenetic, 
 i.e., young are produced from eggs which have not been 
 made fertile by the entrance into them of the sperms (re- 
 productive cells of the male). 
 
 12. ECHINODERMATA 
 
 This phylum derives its name from the rough or spiny 
 skin common to many of the species, such as the starfish 
 and the sea urchins. All of the members of this group 
 dwell in salt water. 
 
 The Starfish (Asterias vulgaris) . Of the several species 
 of starfish living at depths of from one to three hundred 
 feet, the larger forms should be chosen for study. They 
 are numerous in the vicinity of oyster beds as they prey 
 on these shellfish, causing great loss to the oyster industry. 
 
 The normal starfish has five arms of equal length, but 
 
162 ANARTHROPODA 
 
 specimens are often found with as few as one or two arms 
 full length and the others appearing as mere buds. This 
 is due to the fact that the arms have been broken off and 
 are just beginning to grow. If all five arms are cut off 
 they will be reproduced. The skeleton of the animal con- 
 
 PlO. 187. Dorsal or top surface of the starfish ; m, madreporic plate. Photo- 
 graph half natural size. 
 
 sists of flat, irregular calcareous plates imbedded edge to 
 edge in a leathery skin containing numerous pores through 
 which fingerlike processes project and function as gills. 
 The madreporic plate forms a sieve through which the water 
 passes into the stone canal leading down to the ambulacral 
 or water-vascular system. The latter consists of a vessel 
 encircling the mouth and sending a branch into each arm 
 to connect with the feet. The numerous feet are visible 
 
ECHINODERMATA 163 
 
 in the five ambulacral grooves on the ventral sides of the 
 arms. The mouth is the circular opening in the center 
 of the ventral surface. 
 
 To study the internal organs place the specimen in a 
 pan of water deep enough to cover it, and with the scissors 
 
 FIG. 188. Ventral or under surface of the starfish. Black circle in the middle 
 is the mouth from which radiate the five ambulacral grooves, each filled with 
 about a hundred feet. Photograph half natural size. 
 
 remove the skin from nearly half the dorsal surface cutting 
 alongside the madreporic plate remaining in place. The 
 saclike stomach occupies the body just beneath the skin 
 and from it bifurcated processes, the pyloric cceca, extend 
 more than half way to the ends of the arms. By slightly 
 raising the skin bearing the madreporic plate, the slender 
 stone canal may be seen leading to the ring around the 
 
164 
 
 ANARTHROPODA 
 
 FIG. 189. Vertical section of one arm of a starfish ; a, anus ; 6, ampulla ; c, car- 
 diac stomach ; ct, connection of pyloric caeca with stomach ; d, stone canal ; i, 
 radial ambulacral vessel ; ft, feet ; m, mouth ; n, cut end of nerve ring sur- 
 rounding the mouth ; py, pyloric caeca ; r, respiratory organ ; rp, ovary ; st, 
 madreporic plate ; stc t stomach. 
 
 mouth. The removal of the pyloric caeca makes visible 
 along the floor of the arm two rows of little bladders, 
 
 FlG. IW. Strongylocentrotus: the green urchin on the left, and Arbacia the black 
 urchin on the right. The green urchin seen from the ventral side shows white 
 teeth filling the mouth and numerous feet among the spines. Photograph half 
 natural size. 
 
 ampullce, which are usually in a collapsed condition. These 
 receive the water from the radial ambulacral vessel extend- 
 
ECHINODERMATA 165 
 
 ing through each arm, and discharge it into the feet by 
 means of which they are extended, then sucked fast to an 
 object, and contracted to pull the animal along. The star- 
 fish has no heart, but a circular blood vessel surrounds the 
 mouth and gives off a branch to each arm. 
 
 The nervous system consists of a ring around the mouth 
 and five radial nerves supplying the arms. This system 
 
 FIG. 191. Sea cucumber (Pentactafrondosa). Photograph natural size. 
 
 is easily seen on the ventral surface by separating the two 
 rows of feet in each ambulacral groove. The male can be 
 distinguished from the female only by a microscopic exami- 
 nation of the reproductive glands, of which there are five 
 pairs lying at the junction of the arms with the body. Each 
 gland with its tip toward the point of the arm may be a 
 half inch long, or if ripe two or three inches long. 
 
 Arbacia of dark color and Strongylocenlrotus of a green- 
 ish hue are common representatives of the sea urchins 
 (Echinoidce) which are characterized by the presence of 
 
166 ANARTHROPODA 
 
 pronounced spines and usually a globular or disk-shaped 
 body without arms. The true urchins are common along 
 muddy coasts, and the sand dollars flat and with short, 
 weak spines are most prevalent along sandy shores. 
 The sea cucumbers (Hokthuroidea) have elongated cylin- 
 
 FlG. 192. A brittle star (Ophiopholis bellis). Photograph natural size. 
 
 drical bodies with a circle of branched tentacles about the 
 mouth, and from it five rows of feet extend posteriorly. 
 They are found in the mud at the water's edge during low 
 tide. 
 
 The brittle stars (Ophiuroidea) have five arms much more 
 slender than those of the starfish and no ambulacral grooves 
 are present. The crinoids (Crincridea) including the feather 
 
ECHINODERMATA 
 
 167 
 
 stars and sea lilies differ from most 
 animals in being attached to some 
 object by a stalk. They usually 
 live at considerable depth in the 
 sea. Fossil remains show that these 
 animals were very abundant several 
 millions of years ago in the- Silurian 
 period. To-day but few species exist. 
 The Echinodermata are lower in the 
 animal scale than most of the preceding 
 phyla, as they have no heart and very 
 simple nervous and excretory systems. 
 The senses of sight and hearing seem to be 
 entirely wanting, and the sense of smell 
 is very little developed. All the species 
 live in the same environment and present 
 the same characteristic radiate structure. 
 
 FIG. 193. Crinoid show- 
 ing the stem with which 
 it is attached. 
 
 13. CCELENTERATA AND PORIFERA 
 
 The two groups of animals discussed in this chapter were 
 formerly placed in the same phylum because they are so 
 
 much alike in hab- 
 its and structure. 
 The stinging or 
 nettle cells pos- 
 sessed by the Coelen- 
 terata and wanting 
 in the Porifera 
 separate clearly 
 
 . 194. Diagrammatic cross section of the body of a 
 coelenterate A, and that of a worm or insect B. the tWO groups. 
 
168 ANARTHROPODA 
 
 Ccelenterata : Hydroids, Jellyfish, and Sea Anemones 
 
 With the exception of a few species all of the Ccelenterata 
 live in salt water. They differ from most of the animals 
 thus far described in having no body cavity (ccelome) sur- 
 rounding the digestive canal and in the presence of only 
 two layers of cells in the body wall. 
 
 Hydra Viridis. This common freshwater polyp may be 
 found in the summer and autumn by placing in several 
 glass jars or aquaria a considerable quantity of duck-meat 
 or duck-weed, together with the water in which it is found 
 growing. This plant is a favorite support for the animals. 
 Place the jars in a north or east window and examine them 
 daily for a week, looking through the water toward the 
 light for a minute creature a fourth of an inch long or less 
 with tentacles. It is usually attached to the side of the 
 jar toward the light. When found it may be transferred 
 with a pipette (medicine dropper) to a watch crystal for 
 study and covered with a few drops of water. 
 
 The structure of the Hydra is that of a simple tube with 
 walls made with two layers of cells, the outer of which is 
 the ectoderm and the inner the endoderm. For securing 
 food there are around the mouth several tentacles bearing 
 stinging cells (nematocysts) containing coiled, whiplike 
 processes which dart forth at the touch of an animal and 
 numb it. The tentacles then slowly work the prey through 
 the mouth into the digestive cavity where digestive juices 
 secreted by some of the cells render parts of it absorbable 
 by certain cells of the endoderm. The undigested portions 
 are cast out through the mouth. Water fleas and algae 
 
CCELENTERATA AND PORIFERA 
 
 169 
 
 FIG. 195. Photograph of living hydras. Each of the 
 two at the right bears a bud. Twice natural size. 
 
 form much of 
 
 their food. No 
 
 vascular, respira- 
 
 tory, or excretory 
 
 systems are pres- 
 
 ent, and the ner- 
 
 vous system is rep- 
 
 resented only by 
 
 a few scattered 
 
 cells. Delicate 
 
 muscle fibers indicate the beginning of a muscular sys- 
 
 tem in the animal 
 kingdom. 
 
 Reproduction oc- 
 curs in two ways 
 by budding and 
 means of eggs. 
 a Hydra be 
 watched a few min- 
 utes each day for a 
 week, a minute bud 
 which is really an 
 outpushing of the 
 wall may be seen 
 to appear and grow 
 larger from day to 
 day for a period of 
 from four to eight 
 days until it as- 
 sumes the form of 
 the mother. It then 
 
 by 
 If 
 
 ?IG. 196. Photograph of Hydra enlarged fifteen 
 diameters. The minute swellings on the ten- 
 tacles at the left are the stinging cells. 
 
170 
 
 ANARTHROPODA 
 
 breaks loose from the parent and leads an independent 
 life. 
 
 The egg which is merely an enlarged and specialized cell 
 near the base of the parent may develop into a complete 
 polyp (Hydra) if one of the numerous male (sperm) cells 
 breaking out of the spermary unites with it. Soon after 
 
 FIG. 197. Longitudinal section of a Hydra ; b, bud which will form a young one ; 
 6a, base by which it is attached when not creeping ; m, mouth ; ov, ovary with 
 an egg ; sp, spermary. 
 
 the union, the egg separates from the parent and dropping 
 to the bottom may remain there over winter before growing 
 into a new animal. 
 
 Hydroids. These are hydralike animals living in the 
 ocean, and frequently growing in colonies. Obelia is a 
 common example on our eastern coast. It is found in 
 colonies attached to boards and seaweeds near the surface 
 of the water. The animals composing the colony are called 
 
. 198. Photograph of a Hydra reproducing ; a,young bud about six hours old ; 
 6, bud four days old ; c, base fixed to a stem. Enlarged thirty diameters. 
 
 FIG. 199. Several hydroid colonies each containing from 10 to 20 animals, growing 
 on a piece of rotten wood in the ocean. The three lowest animals on the tafl 
 colony in the middle are reproductive polyps. Photograph enlarged four 
 diameters.. (171) 
 
172 
 
 ANA&THBOPODA 
 
 FIG. 200. Several hydroid colonies (Sertu- 
 larid) each containing from 20 to 30 animals. 
 Photograph enlarged three diameters. 
 
 zoophytes or polyps and 
 each has the same 
 structure as the Hydra. 
 There are two kinds of 
 polyps One is known 
 as the feeding polyp, 
 and has for its func- 
 tion the securing and 
 digesting of food to be 
 distributed throughout 
 the colony; the other is 
 
 the reproductive polyp or Uastostyle, which produces the 
 
 young. The food polyps are recognized by the tentacles 
 
 absent in the blastostyles which 
 
 contain biscuit-shaped bodies, the 
 
 medusae buds. These one by one 
 
 emerge as minute umbrellalike 
 
 forms called medusce. , . 
 They swim about freely, never 
 
 attaining a sufficient size to be 
 
 seen clearly with the naked eye, 
 
 and the female produces eggs, 
 
 while the male gives forth sperm 
 
 cells each of which uniting with 
 
 an egg fertilizes it, i.e., renders it 
 
 capable of developing into an ani- 
 mal. The young one soon fixes 
 
 itself to a weed or stick, and in a 
 
 few weeks by producing budding 
 
 young like the Hydra forms a 
 
 colony. The hydroids are there- 
 
 FIG. 201. A hydroid colony of 
 six polyps ; /, feeding polyp ; 
 r, reproductive polyp ; m, a 
 medusa. 
 
CCELENTEEATA AND PORIFERA 173 
 
 fore said to exhibit alternation of generations) i.e., the egg 
 of the medusa generation does not hatch into a medusa, 
 
 FIG. 202. Half of a jellyfish ; a, two of the four arms around the mouth m ; r, 
 reproductive organs ; st, stomach ; t, tentacles 
 
 but develops into a fixed colony some of whose polyps 
 produce medusa? (small jellyfish). 
 
 The large jelly fishes of the ocean, which are similar hi 
 structure to the medusse just described, attain a diameter 
 of several inches and possess tentacles a foot or more long 
 
174 
 
 ANARTHROPODA 
 
 bearing nematocysts. The stinging sensation one experi- 
 ences upon picking up a jellyfish is caused by the discharge 
 
 FIG. 203. Development of young jellyfish. The top one is ready to break away 
 After Haeckel. 
 
 of these coiled stinging processes. Each egg deposited by 
 the jellyfish produces a free- 
 swimming young, which soon 
 fixes itself to an object and 
 assumes a form similar to the 
 hydra and grows to the height 
 of half an inch. It then be- 
 comes transversely divided into 
 several parts, giving the animal 
 the appearance of a pile of 
 saucers. The top one soon 
 swims free, and one by one the 
 
 others are also separated and turning upside down lead 
 the free life of the adult forms. 
 The sea anemones may be seen at low tide attached firmly 
 
CCELENTERATA AND PORIFERA 
 
 175 
 
 to the rocks and wharves a short distance beneath the sur- 
 face of the water. They vary in diameter from a fourth 
 of an inch to two 
 feet. Themoment 
 they are disturbed 
 the numerous ten- 
 tacles around the 
 mouth are con- 
 tracted, and the 
 fleshy mass be- 
 comes a brown 
 conical body. 
 
 The coral polyp 
 is similar to the 
 anemone, but much 
 smaller. It secretes 
 from the sea water 
 lime which is de- 
 posited throughout 
 its tissues to form 
 a skeleton. Most 
 corals, like the hydroids, bud freely and thus great masses 
 of coral are formed. They dwell only in the warmer parts 
 of the ocean. 
 
 Porifera: Sponges 
 
 The sponges are mostly ocean dwellers, only about thirty 
 species being found in fresh water. A simple sponge, such 
 as Grantia or Leucoselenia, growing near the surface of the 
 water on logs and stones along the Atlantic coast, has 
 much the same structure as Hydra, but the walls composed 
 
 FIG. 205. Coral. Each of the two thousand or 
 more small projections is the work of one coral 
 polyp. Photograph, one third natural size. 
 
176 
 
 ANARTHROPODA 
 
 of three layers are perforated by numerous minute pores 
 for the passage of water and food. The larger sponges are 
 of a more complex nature. 
 
 The body of a sponge in addition to the fleshy material 
 consists in some species of flexible fibers of spongin, such as 
 make up entirely the commercial sponge when purchased. 
 
 In other species 
 like Grantia, 
 lime spicules are 
 present, and in a 
 few kinds, in- 
 cluding the fresh 
 water forms, sil- 
 icious spicules 
 occur. 
 
 The fresh 
 water sponges 
 have a wide dis- 
 tribution, and 
 may be found 
 by looking for irregular more or less lobed cushionlike 
 masses from one to four inches in diamster attached to 
 weeds, logs, and stones in clear springs and ponds. 
 
 Sponges reproduce by eggs and also by internal buds 
 called gemmules. 
 
 In the ocean, sponges are found at depths of from one 
 to six hundred feet. The most famous sponge fisheries 
 are those of the Great Bahama Bank in the West India 
 region, and those of the Mediterranean and Red Seas. 
 All sponges came from the Mediterranean Sea prior to the 
 year 1840, when the famous fisheries were discovered along 
 
 - A fresh water sponge. Photograph natural 
 size. 
 
CCELENTERATA AND PORIFERA 177 
 
 the Bahama Islands. Seven or eight hundred craft are 
 now engaged in the sponge regions of the West Indies, 
 where the shallow water permits them to hook up the 
 animals with a 
 long-handled three- 
 pronged fork In 
 the Mediterranean 
 Sea the finest 
 sponges grow at 
 a depth of two 
 hundred feet or 
 more, and can be 
 secured only by 
 divers, many of 
 whom work with- 
 out diving suits 
 and remain under 
 water as long as 
 three minutes. The 
 deepest sponges are 
 brought up with 
 drag nets. 
 
 The skeleton Of ^ IG " 207 -~ A salt water sponge. Photograph half 
 . natural size. 
 
 the commercial 
 
 sponge composed of fine spongin fibers is cleaned free of the 
 fleshy portion by means of bacteria which cause all flesh to 
 decay or rot. Some species of sponges are found growing 
 only on the backs and legs of certain crabs which are thereby 
 concealed from their enemies. The crab favors the sponge by 
 carrying it to new feeding grounds. Such mutually help- 
 ful association between animals is termed commensalism. 
 
178 ANARTHROPODA 
 
 14. PROTOZOA: ONE-CELLED MICROSCOPIC ANIMALS 
 
 The members of this phylum are single-celled animals, 
 and so small that but few of them can be seen with the 
 naked eye, and some are so minute as to be visible only 
 under the highest powers of the microscope. They abound 
 in the dust of the air, in the surface layers of the earth, 
 and in the water, while many parasitic forms make their 
 homes in the living bodies of the higher animals and plants, 
 sometimes causing disease. 
 
 Slipper Animalcule (Paramoecium). This is a repre- 
 sentative of the class Infusoria, which includes most of the 
 
 protozoa commonly pres- 
 ent in infusions made by 
 soaking grass, leaves, or 
 flowers in water. Para- 
 moecia may usually be se- 
 cured by placing a bunch 
 
 FIG. 208. Slipper animalcule showing t i <,,. i^ fl plioV, n f 
 
 the nucleus, a dark circle, and the 
 
 buccai groove on the lower side. En- stagnant water f or a week 
 
 larged two hundred diameters. 
 
 or two. 
 
 For study, a small drop of water containing a number 
 of specimens should be transferred to a glass slip, and one 
 or two minute threadlike green plants added to the drop 
 before the cover glass is placed thereon. Having seen with 
 the low power that the animals wanted are present in the 
 mount, absorb with blotting paper the superfluous water 
 about the edge of the cover glass, drop near its margin a 
 half dozen pieces of paraffin, and with a red-hot nail 
 held in a cork melt the paraffin so it runs slightly over the 
 
PROTOZOA 
 
 179 
 
 edge of the cover glass and thus makes an air-tight 
 aquarium. I have kept amoeba and some of the smaller 
 infusoria alive in this way over two months. The Para- 
 mcecia usually live only a few days. The preparation must 
 be kept in the light, not sun, so that the plants will give 
 off the oxygen ne- 
 cessary to the life 
 of the animals and 
 also consume their 
 excreted carbon 
 dioxide. 
 
 The movement 
 of the animal is 
 effected by short, 
 hairlike processes 
 (cilia) covering 
 the entire surface. 
 The buccal groove 
 beginning on one 
 side opens into a 
 mouth permitting 
 the food to pass through a short gullet into the soft in- 
 ternal protoplasm (cell contents). They feed largely 
 on bacteria. Near either end of the body may be seen a 
 clear round spot, the contractile vacuole, which is an exit 
 for the surplus water. 
 
 Paramoecium, like all other infusorians, reproduces by 
 binary fission, i.e., divides its body into two equal parts, 
 each of which in a day or two grows to the normal size. 
 This process of division is easily seen, as about a half hour 
 is required for its completion. Each of the new genera- 
 
 FlG. 209. Living Paramcecia photographed through 
 the microscope magnifying eighty diameters. 
 
180 
 
 ANARTHROPODA 
 
 tion is ready to divide again within twenty-four hours if 
 the conditions are favorable. After the formation of a 
 hundred or more generations they seem to become ex- 
 hausted and must then be rejuvenated by a process called 
 conjugation. This is the union of two individuals along 
 their ventral surfaces by means of which a mutual ex- 
 change of protoplasm occurs. They then separate, and 
 each is ready to divide again. 
 
 Bell Animalcule (Vorticella). This is another infusorian 
 common in stagnant water. It is easily recognized under 
 
 the low power of the 
 microscope by its 
 bell-shaped body 
 attached to a stem 
 which occasionally 
 contracts into a 
 spiral. The cilia 
 around the mouth 
 are used to form 
 a vortex drawing 
 the food into its 
 gullet leading 
 blindly into the 
 soft protoplasm. 
 
 Amoeba. This 
 genus includes sev- 
 
 FIG. 210. Photograph of a living bell animalcule, 
 enlarged two hundred diameters. 
 
 eral species of the class Rhizopoda (root-footed), which are 
 regarded as being the lowest in the scale of animal life. 
 Seldom does one become large enough to be seen with the 
 naked eye, but it is easily distinguished with a magnifica- 
 tion of one or two hundred diameters. In some regions 
 
PROTOZOA 
 
 181 
 
 the Amoeba is not easy to secure, but if a few sticks and 
 leaves with their accompanying ooze from a stagnant pond 
 be placed in a dish of water in an east or north window, 
 
 FIG. 211. A, Amoeba proteus; B, Amoeba radlosa. n, nucleus; c, contractile 
 vacuole ; a, food engulfed ; ec, one of the nine pseudopods. After .Leidy. 
 
 and a little green scum or water alga3 added, large numbers 
 usually develop. To secure them for study, scrape a little 
 of the slime from a stick or leaf upon a glass slip, place on 
 the cover glass, and examine with the low power. An 
 
182 AHAHTHROPODA 
 
 Amoeba may be recognized by its slow crawling and fre- 
 quent changes in shape as it puts forth the blunt processes 
 called pseudopods. It appears like a mass of granular color- 
 less protoplasm streaming along inside of & transparent sac 
 known as the ectosarc. It has no mouth but secures food 
 by wrapping itself about any organic material which then 
 passes through the ectosarc into the soft protoplasm, called 
 endosarc, capable of digesting it. The products excreted 
 by the lungs and kidneys of the higher animals are also 
 excreted by the one cell forming the amoeba. 
 
 For continued study, the Amoeba should be mounted as 
 directed for Paramcecium. Some of them may then be 
 seen taking on globular shapes and surrounding themselves 
 with a kind of cyst or coat. In this condition they are said 
 to be encysted, and are capable of thus existing in a dried 
 state for months. While encysted they often divide into 
 several parts called spores, each of which upon the bursting 
 of the cyst forms a complete animal. They also reproduce 
 by binary fission, but this method is not common. 
 
 Parasitic Forms. Several species of protozoans are 
 dwellers in the higher groups of animals from worms to 
 man. Amceba coli lives in the intestines of man and causes 
 a severe kind of dysentery. Plasmodiwn malarice is always 
 present in the blood corpuscles of patients suffering from 
 any of the malarial fevers. Mosquitoes of the genus 
 Anopheles (Fig. 371) transfer the parasites from the sick 
 to the healthy, and thus a large part of an entire community 
 may become infected with this germ. It belongs to the 
 class Sporozoa, which is so named because the animals in 
 reproducing divide into a number of small bodies called 
 spores. 
 
PROTOZOA 
 
 183 
 
 FIG. 212. Photograph of human red blood corpus- 
 cles two of which contain the malarial parasite. 
 Enlarged one thousand times. 
 
 Chalk formers. 
 
 The Globigerince 
 
 are among the most 
 
 abundant protozoa 
 
 in the sea. Nearly 
 
 all surround them- 
 selves with a shell 
 
 of soft calcium car- 
 bonate (chalk). A 
 
 pint of ocean water 
 
 in the warmer 
 
 climes may contain 
 
 millions of them. 
 
 The shells of the 
 
 dead dropping to 
 
 the bottom of the ocean have formed a thick layer of ooze 
 
 over much of the ocean bed. The great chalk cliffs in 
 England, and the chalk beds 
 in Ireland, Denmark, Central 
 Europe, North Africa, Syria, 
 Central Asia, Texas, Kansas, 
 and South Dakota are com- 
 posed almost entirely of the 
 shells of GlobigerinaB that lived 
 ten millions of years ago or 
 more. The small piece of chalk 
 used by the carpenter is made 
 of millions of the skeletons of 
 these tiny protozoans. 
 The protozoa were no doubt 
 
 FIG. 213. Shell of Globigerina. r 
 
 Photograph enlarged forty diameters, the first animals On earth, 
 
184 
 
 ANARTHROPODA 
 
 FIG. 214. Photograph of the Protozoans in one twentieth of a drop of stagnant 
 water. 
 
 and inasmuch as two new animals are formed by the halving 
 of the parent the tiny creatures may never die of old age, 
 but so long as food and environment are favorable live 
 millions of years. They are therefore sometimes spoken 
 of as the immortal animals. The Protozoa are most numer- 
 ous in stagnant water where as many as ten thousand may 
 be present in a single drop. Ordinary drinking water, 
 however, seldom contains more than a dozen in a quart, 
 and good spring water often has none, 
 
PART III 
 VERTEBRATA 
 
 15. PISCES 
 
 THE four chief orders of this class are the round-mouthed 
 fish (Cyclostomata), the cartilaginous fish (Elasmobranchii) , 
 the bony fish (Teleostomi), and lung fish (Dipnoi). 
 
 FIG. 215. Ocean lamprey. Photograph one fourth natural size. The holes oi\ 
 the side behind the eyes are the gill openings. 
 
 135 
 
186 
 
 VERTEBRATA 
 
 Round-mouthed Fish. There are about a dozen species 
 in this country, of which the commonest is the ocean lam- 
 prey (Petromyzon marinus) attaining a length of more than 
 
 two feet. It as- 
 cends the streams 
 along the Atlantic 
 coast to the distance 
 of more than a hun- 
 dred miles for the 
 purpose of spawn- 
 ing, which in the 
 latitude of New York 
 occurs about the 
 middle of May. The 
 
 FIG. 216. Photograph of the mouth of a living lam- nest is made of 
 prey sucked fast to a piece of glass. Natural size. 
 
 gravel and sand en- 
 circled by stones nearly as large as a man's head, which 
 they suck fast to with their peculiar mouth and drag 
 
 FIG. 217. Median longitudinal section of the anterior fourth of a lamprey eel. 
 6, brain ; c, spinal cord ; m, muscles of the back ; n, notochord ; I, liver ; h, 
 heart. Photograph. 
 
 together. The larval young (Ammoccetes) bury themselves 
 in the mud along the banks of the streams, where they 
 remain three or four years until transformation to the adult 
 
PISCES 187 
 
 state occurs. They then descend to the ocean and remain 
 there several years, after which they return to the scene 
 of their youth for breeding purposes, and a few days later 
 die without having regained the ocean. The adult is a 
 parasite living on the blood and mucus rasped from the 
 sides of fish. The lake lamprey of New York is probably 
 a descendant of the ocean lamprey, having been cut off 
 from the salt water by the drying up of the streams many 
 years ago. It is destructive to food fishes, preying on 
 nearly thirty different species. 
 
 The lampreys are not true fish, as they lack paired fins 
 containing spines or bony rays, and have only one nostril, 
 which opens on top of the head in the median line. Jaws 
 are wanting. The skull is made of membrane and carti- 
 lage, and the spinal cord lies in a fibrous tube with bars 
 of cartilage along the sides. Beneath the spinal cord is a 
 stiff gelatinous rod known as the notochord, which is pres- 
 ent in the very young stages of all vertebrates, but usually 
 its place is later occupied by the bodies of the bony verte- 
 bra? (Fig. 227). 
 
 Cartilaginous Fish. The fish whose skeletons are made 
 of cartilage instead of bone live in salt water. They are 
 the sharks and rays. Many of them are predaceous crea- 
 tures, and their presence accounts for the scarcity of some 
 of the species of fish desired for food by man. 
 
 The sharks are represented along our coast by several 
 species, of which the best known is the dogfish (Squalls 
 acanthias), which attains a length of three feet. During 
 the summer it congregates in great numbers along the 
 Maine and Massachusetts coasts, and often prevents the 
 fishermen from catching any codfish by seizing the bait 
 
188 VEBTEBRATA 
 
 the moment it is thrown into the water. In 1883 their 
 vast numbers completely destroyed the fishing. They bit 
 the sails or oars hanging over, and even attacked persons 
 falling overboard. They were caught by the thousands, 
 their livers being used for oil and their bodies carted to 
 
 FlG. 218. The young of the dogfish removed from the body of its parent. Ventral 
 aspect showing the attachment of the large yolk sac to the body, and also the 
 crescentic mouth. Five gill slits are seen on one side. Photograph half natural 
 size. 
 
 the farms for fertilizer. They feed upon refuse and smaller 
 fish. 
 
 The blue sharks and basking sharks of the northern Atlan- 
 tic reach a length of over thirty feet, while the Indo- Pacific 
 basking shark is known to exceed forty feet in length. The 
 man-eater or white shark, ranging from the Atlantic coast 
 to Australia, seldom attains a size of more than thirty feet. 
 
PISCES 189 
 
 In some species of sharks the young are born alive, but 
 in others the eggs are deposited in a tough, usually flattened 
 case with tendrils by which it may be fixed to seaweeds. 
 Most of the one hundred and fifty species of sharks are 
 characterized by five gill openings on either side of the head, 
 underneath which the mouth is situated. 
 
 The rays differ from the sharks in having the gill open- 
 ings beneath the flat disk formed by the body and the ex- 
 panded pectoral fins. The common skate of our Atlantic 
 coast (Raja erinacea) grows to a length of nearly two feet 
 and is nearly as broad. The sawfishes, some of which are 
 fifteen feet long, are remarkable for the prolongation of the 
 snout in a saw-edged sword nearly one fourth the length 
 of the fish. They range from Cape Cod southward. Not 
 less noted is the electrical fish (Torpedo marmoratus) found 
 along the New England coast. A specimen two or three 
 feet long is capable of imparting a severe shock to any one 
 seizing it along the sides of the body. 
 
 Bony Fish (Teleostomi). This order is made up of 
 
 FIG. 219. The bull head (a catfish). Photograph one fourth natural size. 
 
 thousands of species which are characterized by a bony 
 skeleton, usually a scale-covered body, and gills protected 
 by a plate projecting backward called the operculum. 
 
190 VERTEBRATA 
 
 The catfishes have a scaleless skin, a pair or two of long 
 barbels (feelers) projecting from the upper jaw, and the 
 first ray of the dorsal and pectoral fins is a stout spine with 
 which the animal can inflict serious wounds. There are 
 nearly a thousand species widely distributed over the world 
 and are highly valued as food. The great catfish of the 
 Mississippi River attains a length of five feet and weighs 
 one hundred and fifty pounds. The Bullhead or horned 
 pout (Ameiurus coins) is common in streams east of the 
 Mississippi. The eggs of some species are deposited under 
 objects in the streams and guarded by the male, while in 
 other species the eggs are carried in the mouth until 
 hatched. 
 
 The suckers are covered with scales, have toothless jaws, 
 
 FIG. 220. Common river Sucker (Catostomus teres). Photograph one third natural 
 size. 
 
 and thick, fleshy lips forming a nearly circular mouth. 
 They feed on plants and small animals. The flesh is used 
 for food, but is rather coarse. 
 
 The herringSj of which there are more than a hundred 
 species, are found in many parts of the ocean, and some 
 come to the fresh water to spawn (lay eggs). The common 
 herring (Clupea harengus), about a foot long, frequents the 
 north Atlantic coast where they associate in shoals number- 
 
PISCES 191 
 
 ing millions and swim near the surface to secure the worms, 
 insects, and crustaceans. They are therefore easily taken 
 in nets. 
 
 The shad (Clupea sapidissima) is an important food fish, 
 passing the greater part of its life in the ocean along the 
 Atlantic and Pacific coasts. When mature it ascends a 
 stream, often traveling more than a hundred miles to de- 
 posit its eggs, numbering many thousands. On these trips 
 the fish are caught with seines. Like the lampreys, a few 
 
 FIG. 221. Photograph of the shad one sixth natural size. 
 
 days after spawning they die. The shad fisheries of the 
 Atlantic coast are worth two millions of dollars annually. 
 The salmon are the most valuable of all the food fishes. 
 The five species of the Pacific coast salmon, canned in such 
 immense quantities, yield an annual revenue of thirteen 
 million dollars. During most of their life they live in the 
 ocean, but ascend a stream, often two or three thousand 
 miles, to spawn, after which they die. It is during their 
 migration for breeding purposes that they are caught in 
 such vast numbers. The quinnat or chinook salmon, attain- 
 ing a weight of fifty pounds, affords the most delicious 
 meat, but they have become somewhat scarce lately owing 
 
192 
 
 VERTEBRATA 
 
 to the vast numbers caught. A few species of salmon 
 inhabit the streams along the north Atlantic coast. 
 
 The trout are the most delicious of all the food fishes. 
 Of these the brook trout (Salvelinus fontinalis), orna- 
 
 Fio. 222. The brook trout. Photograph one third natural size. 
 
 men ted with red spots, is the most famous. It inhabits 
 the cold streams from Maine to Dakota, and is often culti- 
 vated in ponds. Owing to insufficient protection by law, 
 the supply is becoming limited. 
 
 The cave fishes are represented by several species in this 
 country, dwelling in subterranean streams. Those living 
 
 PIG. 223. Photograph of the common mackerel one third natural size. 
 
 in the Mammoth Cave of Kentucky are white and entirely 
 blind. Their ancestors possessed eyes, but lack of use 
 throughout many generations resulted in blindness. Quite 
 as remarkable as the cave fish are the flying fish of the ocean. 
 They dart obliquely out of the ocean and spread the broad 
 
PISCES 193 
 
 fins which act as parachutes, enabling them to soar through 
 the air nearly an eighth of a mile. 
 
 The sea horse (Hippocampus) is a member of the pipe- 
 fish family. It is only a few inches long, and dwells in the 
 ocean. The male cares for the young in an abdominal 
 pouch. 
 
 The codfishes number ninety species, of which Gadus 
 callarius is the most important. It reaches a length of 
 four feet. In November each mature female deposits 
 about ten millions of eggs which hatch floating on the sur- 
 face of the sea. Vast numbers of codfish are caught with 
 hooks and lines along the north Atlantic and Pacific coasts, 
 and are much valued for food both in the fresh and salted 
 state. 
 
 The mackerels include about seventy species, all living 
 in salt water. They frequent the northern shores at the 
 spawning season in early summer when they appear in 
 large schools. At this time great numbers of the common 
 mackerel (Scomber scombrus) are taken in nets along the 
 New England coast. Those not sold fresh are packed in 
 brine. 
 
 The sunfishes number a dozen species in the United 
 States. The green- sunfish (Lepomis cyanellus), six or seven 
 inches long, is common in the small streams east of the 
 Mississippi. In early summer it forms a nest more than a 
 foot in diameter in shallow water. Coarse gravel lines the 
 margin of the concave area and near the center very fine 
 gravel is present on which the eggs are deposited. The 
 male remains over the nest, keeping it clear of dirt with 
 the tail, until the eggs, of wliich there are several thousand, 
 hatch. 
 
VERTEBRATA 
 
 FlG. 224. Green sunfish on her nest. Photograph one fifth natural size. 
 
 The flatfishes or flounders are valuable food fish of the sea. 
 The halibut is the largest, weighing four hundred pounds, 
 but the flounder (Pleuronectes americanus) is most fre- 
 quently seen in market. It is remarkable for having two 
 eyes on one side of the head and none on the other. It 
 swims on the side, the lower surface, which is white, always 
 remaining in that position. The young are symmetrical, 
 having an eye on either side of the head and swimming 
 upright. 
 
 Lungfishes (Dipnoi). In this order only three species 
 are included. They live in Australia, Africa, and South 
 
PISCES 
 
 196 
 
 FIG. 225. Photograph of the flounder from the lower side. Half natural size. 
 
 America. The feature from which the group takes its 
 name is the possession of a lung or lungs corresponding in 
 position to the air bladder in other fish. Gills are also 
 present, so that these fish can live either in water or on land. 
 
 PIG. 226. Lepido siren, the South American lungfish. Photograph one fourth 
 natural size. 
 
196 VERTEBRATA 
 
 The African mudfish buries itself in. the mud for several 
 months during the dry season. 
 
 The members of the class Pisces are distinguished from 
 all other vertebrates by the absence of limbs, the presence 
 of gills throughout their entire life, and a simple heart con- 
 sisting of only one auricle and one ventricle. The fish, 
 amphibians, and reptiles are often referred to as the cold- 
 blooded animals and the other two classes, birds and 
 mammals, as warm-blooded animals. This distinction is 
 due to the fact that the two higher classes maintain a con- 
 stant temperature of from ninety-eight to one hundred 
 and five degrees Fahrenheit whether the surrounding at- 
 mosphere be hot or cold. A fish, frog, or snake varies its 
 temperature in accordance with that of the atmosphere. 
 In winter they may have a temperature near the freezing 
 point, while in summer it may be almost a hundred degrees. 
 
 The air bladder, present in all forms except the round- 
 mouthed fish, flatfish, sharks, and rays, lies on the dorsal 
 side of the body cavity above the alimentary canal and 
 in some, such as the herring and trout, opens by a duct 
 into the pharynx. Usually, however, the contained gas 
 is given off through the walls. Its function is to aid the 
 fish in maintaining its position in the water. 
 
 To understand the parts of a fish one of the smaller 
 species, such as the catfish, sunfish, or porgy, should be 
 dissected after the external features have been noted. An 
 eye lies in a deep socket on either side of the head, and 
 is capable of rotation in several directions by means of 
 muscles. No eyebrows or eyelids are present, as in higher 
 forms. The nostrils are two pairs of small openings near the 
 tip of the nose. They lead into the nasal cavity over which 
 
PISCES 197 
 
 the olfactory nerve, the nerve of smell, is distributed. This 
 cavity does not communicate with the mouth, as in the 
 Dipnoi and all the higher vertebrates. There is no external 
 ear. The scales, overlapping each other like the shingles of 
 a house, are calcified outgrowths of the skin to protect 
 the body. The unpaired dorsal fins vary from one to three. 
 A pair of pectoral fins is present just back of the gill open- 
 
 FIG. 227. Dissected fish, a, air bladder ; b, urinary bladder ; 6r, brain ; c, spinal 
 cord ; d and da, dorsal fins ; dv, anal fin ; e, body of the vertebrae ; g, gills re- 
 ceiving the blood from the ventral aorta leading out of the heart h ; i, intestine ; 
 k, kidney ; I, liver ; m, spines of the vertebrae ; n, auricle of the heart ; ov, 
 ovary ; ovd, oviduct ; st, stomach ; sp, spleen ; M, ureter. Drawing by W. H. 
 
 ing, and behind and below these is usually a pair of ventral 
 fins. The anal fin present in some forms is single, and 
 behind the opening of the alimentary canal. By removing 
 the entire ventral abdominal wall, most of the organs may 
 be seen. 
 
 Teeth are usually present not only on the jaws, but in 
 some species on the vomer at the roof of the mouth and 
 on the gill arches. Vertical openings between the four 
 
198 VERTEBRATA 
 
 gill arches are the gill slits permitting the water to pass 
 from the pharynx to the exterior. The flap covering 
 the gills externally is the operculwn. A narrow tube, the 
 gullet or esophagus, leads from the large pharynx to the 
 stomach, from which extends the somewhat tortuous intes- 
 tine to its opening at the root of the tail. The liver may 
 be recognized by its large size and red color. 
 
 The intestine, as well as the other organs, is held in place 
 by a transparent membrane known as the mesentery. This 
 is a part of the peritoneum, which appears as a thin, glisten- 
 ing membrane lining the entire abdominal cavity and 
 closely enveloping most of the organs therein. The elon- 
 gated narrow white organ is the pancreas, adjacent to which 
 there is in most species a small dark red body, the spleen. 
 The reproductive organs lying dorsal of the stomach are 
 white in the male and yellowish in the female. The air 
 bladder with a wall as thin as paper is of a grayish-white 
 color, and lies against the spinal column. To see the 
 kidneys, one must look carefully for a pair of flattened 
 brown bodies lying closely against the vertebral column 
 in the dorsal side of the body cavity. 
 
 With a heavy knife the top of the skull may be removed, 
 and the parts of the brain with several of the ten pairs of 
 nerves issuing from its ventral aspect noted. By cutting 
 away the roof of the spinal column, the spinal cord, and 
 each nerve connected with it by two roots may be observed. 
 The eye cut into with a sharp knife reveals three coats: 
 an outer tough one, the sclerotic; a thin black one, the 
 choroid; and an inner pinkish one, the retina. The almost 
 round crystalline lens lies between the watery or aqueous 
 humor contained in the front chamber of the eye and the 
 
AMPHIBIA 199 
 
 glassy or vitreous humor filling the posterior chamber of 
 the eye. The ear composed of the three semicircular 
 canals opening into the oval sac, called the vestibule, may be 
 seen in part by shaving off the side of the skull in the pos- 
 terior part. 
 
 16. AMPHIBIA 
 
 The Amphibians, often called Batrachians, derive their 
 name from the fact that many of the species live a part 
 of their life on land and breathe by lungs, while the other 
 part is spent in the water where gills must be used. The 
 members of this class are distinguished from both the fish 
 and the reptiles by the absence of scales. They are divided 
 into three orders, the Urodela, Anura, and Gynmophiona. 
 
 
 FIG. 228. Photograph of newts nearly natural size. 
 
VERTEBRATA 
 
 Urodela: Salamanders 
 
 This order is characterized by the presence of a tail. 
 The neivt (Diemyctylus viredescens) may be seen from 
 March to December in quiet ponds of water and captured 
 
 FIG. 229. Photograph of large blunt-nosed salamander fouad under a stone at the 
 water's edge, One third natural size. 
 
 FIG. 230. Photograph of Amblysloma opacum half natural size. 
 
 with the net for the aquarium. It relishes bits of beef 
 and earthworms, and will devour a hundred mosquito 
 larvae daily. 
 
AMPHIBIA 201 
 
 The large blunt-nosed salamander (AmUystoma tigrinum) 
 and the gray species (Amblystoma opacum) may often be 
 dipped up with a long-handled net from the sluggish waters 
 near woodlands where they come in early spring to 
 breed. The eggs, numbering several hundred, appear like 
 shot in a colorless, jelly like mass of albumen as large 
 as the human fist. 
 
 The red-backed salamander (Plethodon cinereus) is com- 
 
 FlQ. 231. Plethodon cinereus. Photograph natural size. 
 
 mon under stones and logs in and near the woods. The 
 mountain salamanders of the genus Desmognathusare often 
 found under the loose stones in the cold forest streams of 
 the liighlands. Though most of the amphibians have 
 lungs in the adult state the species of the genera Spelerpes 
 and Plethodon have neither gills nor lungs when mature. 
 The blood is relieved of its carbon dioxide and receives 
 oxygen by means of the capillaries lying near the surface 
 
202 
 
 VERTEBRATA 
 
 FlG. 232. Home of the salamanders. 
 
AMPHIBIA 
 
 203 
 
 of the skin and in the mucous membrane of the mouth 
 and throat. 
 
 The mud puppy (Necturus maculatus), abundant in 
 the Great Lakes and the waters near by, is remarkable 
 
 FIG. 233. Desmognathus, the mountain salamander. Photograph natural size. 
 
 in that it possesses both gills and lungs in the adult state. 
 Like characters are exhibited by the blind salamander (Pro- 
 teus anguineus) in the caves of Austria and an allied form 
 
 FIG. 234. Photograph of Amblystoma eggs in water. Natural size. 
 
 found in the caves of Texas. The hellbender (Crypto- 
 branchus alleghaniensis) is the largest of our salamanders. 
 It lives in the streams of the Ohio and the Susquehanna 
 valleys. The congo snake, which reaches a length of 
 nearly three feet, inhabits the ditches and stagnant ponds 
 
204 VERTEBRATA 
 
 from Arkansas to North Carolina. Its limbs, two or three- 
 toed and less than an inch long, illustrate the effect of dis- 
 
 FIG. 235. The mud puppy or water dog, showing the gills projecting from either 
 side of the neck. Photograph one third natural size. 
 
 use of an organ. The mud eel (Siren lacertina) of South 
 Carolina is similar to the congo snake in habits and form, 
 but has no poste- 
 rior limbs and ex- 
 hibits external 
 gilts like the mud 
 puppy 
 
 Anura : tailless 
 * Amphibia 
 
 This order in- 
 cludes the frogs 
 and toads which 
 are found in nearly 
 all parts of the 
 
 FIG. 236. Photograph of fbo congo snake one third 
 WOrld. In the natural sizfc 
 
FIG. 237. The green frog, showing the tympanic 
 membrane (ear drum) just back of the eye. Pho- 
 tograph half natural size by Overton. 
 
 AMPHIBIA 205 
 
 adult stage they are provided with lungs, but respiration 
 is carried on to a large extent through the skin, especially 
 in the frogs spend- 
 ing much time under 
 the water. 
 
 The bull frog 
 (Rana catesbiana) is 
 the only amphibian 
 much valued for 
 food. The length of 
 a full-grown speci- 
 men from the tip of 
 the nose to the end 
 of the outstretched 
 hind legs is nearly two feet. It may be distinguished from 
 
 the other frogs by the 
 fact that the web of the 
 foot reaches to the tip of 
 the fourth toe and the 
 back is of a greenish color 
 with small faint dark 
 spots. Thousands of dol- 
 lars' worth of frogs' legs 
 are sold annually in the 
 city markets. The green 
 frog (Rana clamitans) is 
 characterized by a tym- 
 panic membrane larger 
 than the eye and the 
 
 FIG. 238. The common tree frog two thirds 
 
 natural size. Photograph was taken just presence of a fold OH 
 after it was transferred from a sheet of 
 
 white paper. Twenty minutes later it was pitViPr csirlp nf 
 the same color as the oak bark. 
 
206 VERTEBRATA 
 
 The commonest of our frogs is the leopard frog (Rana 
 pipiens) distinguished by the two rows of irregular black 
 
 blotches on the back and 
 the bars on the upper surface 
 of the legs. 
 
 The tree frogs or tree toads 
 are so named from their 
 habit of climbing trees, to 
 which they adhere by means 
 of small expansions at the 
 extremities of the toes. 
 They have the power to 
 change their color to har- 
 monize with their surround- 
 ings. The common tree frog 
 (Hyla versicolor) is the one 
 FIG. 239. The spring peeper, photo- giving the high trilling note 
 
 graph natural size. , . ,, 
 
 prophetic of the approach- 
 ing storm; The Spring peeper (Hyla pickeringii) an- 
 nounces the coming spring by its clear shrill whistle 
 " Uh-e-e-t, wh-e-e-t, wh-e-e-t," 
 uttered so continuously at night- 
 fall that every meadow and swamp 
 seems to be the home of thou- 
 sands. They may be caught by 
 wading among them with a lan- 
 tern and then remaining quiet 
 about ten minutes until one moves FIG. 240. -The toad one third 
 sufficiently near to be grasped. natural 8ize * 
 
 Toads differ from frogs in having no teeth in either jaw, 
 and usually the skin presents a warty appearance. The 
 
AMPHIBIA 207 
 
 frogs prefer moist places, but the toads seek a dry habitat 
 in yards and gardens 
 where they are of great 
 service in destroying 
 flies, slugs, and noxious 
 insects. One hundred 
 and forty-nine toad 
 stomachs examined by 
 Kirkland showed three 
 fourths of the food to 
 consist of insects of 
 which one fourth were 
 cutworms and tent cat- 
 erpillars. The stomach 
 
 Of Olie toad Contained FlG 241 ._ Larva of Amblystoma and of the 
 fifty-five army WOrms ^ r g three months old. Photograph natural 
 
 and that of another 
 
 thirty-seven tent caterpillars. Bufo lentigenosus is the 
 
 only species of toad east of the Rocky Mountains. 
 
 Gymnophiona 
 
 The members of this order are tailless and limbless 
 forms, living in Southern India, Southern Africa, and Cen- 
 tral and South America. They are covered with scales, 
 and in other ways resemble snakes. 
 
 The breeding habits of the majority of the amphibians 
 are similar. The eggs are usually deposited in the water, 
 but the congo snake protects hers beneath a log or stone, 
 while a South American frog, Pipa, carries the eggs im- 
 bedded in the skin of the back. The eggs of most of the 
 
208 VERTEBRATA 
 
 frogs and the Amblystoma appear as dark bodies of pin- 
 head size imbedded in a mass of clear, jellylike albumen. 
 The eggs of the toad are deposited in strings. The newt 
 fastens its eggs singly within little tufts of aquatic leaves, 
 while Plethodon hides its eggs under stones arid logs on 
 land. 
 
 The time of year when the various species breed extends 
 from March to October. The eggs of the Amblystoma and 
 the leopard frog are found as soon as the snow melts in 
 the spring, while the green frog and brown frog spawn in 
 April. In May or June the common tree frog attaches its 
 eggs in small masses to stems of weeds and grass in shallow 
 pools, and the bullfrog seldom spawns before July. The 
 toad scatters its strings of eggs over the stones and brush 
 in any small pool or pond during late April and early May. 
 The breeding season of the newts extends from April to 
 July, and some of the large urodels lay their eggs in the 
 autumn. 
 
 The young of the amphibians are known as larvce or tad- 
 poles. They dwell in the water and breathe by means of 
 gills. In the case of frogs and toads, the food consists 
 largely of vegetable matter, which fact accounts for the 
 great length of the intestine in these forms. The intestine 
 of the adult feeding on animals is not one fourth as long as 
 that of the larva. The Amblystoma larvaB feed on aquatic 
 insects, such as mosquito larvae and pupae, and therefore 
 have a short intestine, as nutrition is easily secured from 
 animal matter. The length of the larval period varies in 
 the different species. For the toad it is usually about two 
 months, while in some frogs it lasts six months and in 
 others more than a year. Many of the salamanders pass 
 
AMPHIBIA 
 
 209 
 
 the winter in the larval stage, and one species of the Ainbly- 
 stoma, the Axolotl, continues throughout life in the larval 
 state, unless forced to terrestrial habits by the drying up 
 of the water. In the Anura, metamorphosis to the adult 
 state involves the absorption of the gills and the tail, and 
 the development of lungs, and an exchange of animal for 
 a vegetable diet. After the first few days of larval life, 
 
 FIG. 242. Frog with the left side cut away and some of the organs pulled down- 
 ward, a, aorta leading from the ventricle ; 6, bladder ; c, spinal cord sur- 
 rounded by the vertebral column of bone ; d, small intestine ; e, opening of the 
 lungs into the pharynx ; h, ventricle of the heart ; k, kidney ; I, lung ; Jiv, liver ; 
 n, brain ; ov, ovary ; ovd , oviduct ; p, pancreas ; r, rectum ; sp, spleen ; st, 
 stomach ; t, tongue ; si, small intestine ; tt, left auricle ; ur, ureter ; v, vena 
 cava ; vc, body of vertebra. 
 
 the frogs and toads do not have external gills like the sala- 
 manders, but the gills are on arches and covered similar to 
 those in fish, but only one opening exists, and that is a small 
 one on the left side just behind the head. 
 
 Dissection. Those wishing to study the structure of 
 this class by making a careful dissection may use any of 
 the salamanders, a large tadpole, or a frog, which can 
 
210 VERTEBRATA 
 
 be easily killed by immersing a quarter of an hour in a 
 half pint jar of water containing an ounce of one per 
 cent chloretone or a quarter of an ounce of chloroform. 
 A frog is preferable for this work. Before killing, its 
 method of respiration and locomotion should be noted. 
 Among the external features to be observed are the moist, 
 smooth skin, the teeth in the upper jaw, the peculiar tongue, 
 the two minute apertures, called external nares, at the tip 
 of the nose, the two eyes, each with two eyelids of which 
 the lower is the more movable, the circular tympanic mem- 
 brane just back of the eye, and the webbed condition of 
 the feet. The three parts of the fore limb are the arm, 
 forearm, and hand, with the four digits corresponding to 
 the four fingers of man. The thumb is scarcely large 
 enough to be noted. The parts of the hind limb are the 
 thigh, leg, and foot, with the five toes webbed together. 
 To study the internal features, cut off with the scissors 
 the entire ventral wall of the abdomen, lay the frog on its 
 back in a waxed-bottom dissecting pan containing enough 
 water to cover the animal. Pin down the sides of the 
 abdominal wall and identify the various organs by the use 
 of the illustration and comparison with the same struc- 
 tures in a fish. If the animal is a male, the sexual glands 
 will be two oval solid yellowish bodies near the kidneys. 
 The delicate membrane supporting the intestine is the 
 mesentery, which is a part of the peritoneum, the thin 
 glistening membrane lining the body cavity and closely 
 surrounding most of the organs. The heart of the amphibia 
 is composed of a ventricle and two auricles in addition to 
 a venous sac and an arterial trunk. The circulation of the 
 blood may be observed under the microscope in the tail 
 
REPTILIA 211 
 
 of a tadpole. To make one lie quiet on a glass slip with a 
 cover glass over its tail, immerse it in the chloretone mix- 
 ture (water one part and one per cent chloretone five parts) 
 until completely unconscious. A drop of blood put on a 
 clean glass slip and at once spread very thin by drawing 
 the end of another glass slip lightly over it will show the 
 oval nucleated red corpuscles characteristic of most of 
 the vertebrates except mammals. 
 
 The brain with its ten pairs of nerves joining its ventral 
 aspect may be seen by cutting away the roof and sides of 
 the skull with a heavy knife. Any one wishing to study 
 the skeleton can render the flesh easily removable by boil- 
 ing the animal an hour or more, depending upon its age, 
 in two quarts of water containing an ounce of soap cut into 
 slices. 
 
 17. REPTILIA 
 
 The reptiles are distinguished from the amphibians by 
 the presence of scales and the fact that the young never 
 breathe by gills. Only three orders inhabit this country. 
 They are the Squamata (snakes and lizards), the Chelonia 
 (turtles and tortoises), and the Crocodilia (crocodiles and 
 alligators. 
 
 Squamata: Lizards and Snakes 
 
 The name of this order is derived from the Latin squama, 
 a scale. The distinguishing feature of the group is the 
 presence of horny epidermal scales covering the surface. 
 
 The Lizards. More than eighty species of lizards are 
 known in North America. They differ from the snakes 
 
212 
 
 VERTEBRATA 
 
 in not having a forked tongue and in having eyelids and an 
 external ear opening on either side of the head. The 
 common lizard (Sceleporus undulatus) is widely distributed 
 over the United States. The skinks or striped lizards are 
 fast runners and abound in the central and southern por- 
 tion of our country. 
 
 The chameleon (Anolis principalis) is the grass green 
 lizard of the South, which is capable of changing its color 
 
 FlG. 243. The horned chameleon from Africa. Photograph two thirds natural 
 
 size. 
 
 to harmonize with its surroundings and thus escape the 
 eyes of the enemy. The chameleon famed in literature is 
 from Africa. 
 
 The glass snake (Ophisaurus ventralis), ranging from 
 Wisconsin to Kansas and south, is remarkable for the com- 
 plete absence of limbs. More than twenty species of limb- 
 less lizards are known. There are a dozen species with 
 
REPT1LIA 213 
 
 hind limbs only, and two or three species in which fore 
 limbs only are present. The study of fossil reptiles shows 
 that the ancestors of these forms had well-developed limbs 
 which degenerated on account of the habits of the animals ; 
 they spend much time in narrow quarters where legs are 
 useless and a hindrance. 
 
 The only poisonous lizard in this country is the Gila 
 monster (Heloderma suspedum) living in Arizona, Cali- 
 
 FIG. 244. The Gila monster. Photograph one fifth natural size. 
 
 fornia, and Mexico. The largest specimens measure nearly 
 a yard. Allied to these are the huge monitor lizards of 
 Africa, India, and Australia, which attain a length of seven 
 feet. Most lizards are oviparous, depositing their eggs 
 in the sand. 
 
 The Ophidia. The snakes, numbering one hundred and 
 fifty species in North America, are much more elongated 
 
214 
 
 VERTEBRATA 
 
 than the lizards, and with the exception of very few species 
 possess no remnants of hind limbs. 
 
 The family Colubridce includes most of our harmless 
 snakes. The commonest of our garter snakes (Thnmnophis 
 sirtalis) frequents yards, gardens, and fields hi search of 
 mice, frogs, and insects. Like all snakes, they swallow 
 
 their prey whole 
 
 and sometimes 
 alive. The lower 
 jaw is so loosely 
 attached to the 
 skull as to permit 
 the throat to be 
 greatly enlarged 
 and the alimentary 
 canal may likewise 
 become much ex- 
 panded owing to 
 the fact that the 
 ribs are not artic- 
 ulated to a breastbone, as in birds and mammals, but 
 terminate freely. The prey after being swallowed may 
 remain alive some time in the stomach. I once shot a 
 water moccasin (Natrix sipedon) and upon opening the 
 stomach an hour later found seven fish, three of which 
 swam away when placed in water. 
 
 The milk snake or spotted adder (Lampropeltis triangu- 
 laris) frequents the neighborhood of houses, and is often 
 mistaken for the copperhead pilot. When disturbed it 
 mimics the poisonous snakes, but is entirety harmless. The 
 black snake or blue racer (Bascanion constrictor) frequents 
 
 FIG. 245. A garter snake two feet long and the 
 frog which it swallowed. Photograph. 
 
KEPTILIA 
 
 215 
 
 FlG. 246. Thamnophis sirtalis three feet long. Photograph. 
 
 FIG. 247. Water snake or moccasin often found along the streams. Three feet 
 long. Below is the skin which it shed entire just before the photograph was 
 made. 
 
216 
 
 VERTEBRATA 
 
 FIG. 248. Spotted adder nearly three feet long. 
 Photograph. 
 
 pasture grounds and 
 woods east of the 
 Mississippi, attains a 
 length of seven feet, 
 but is entirely harm- 
 less. It is fond of 
 birds' eggs and birds 
 which it often climbs 
 trees to secure. 
 
 Crotalidce is the 
 family including all 
 our poisonous snakes, 
 except one species, 
 the bead snake, rang- 
 ing from Virginia to 
 Arkansas and the 
 
 South. There are no external features which enable one 
 
 to determine with 
 
 certainty at sight 
 
 whether any snake 
 
 is venomous or 
 
 harmless, but a 
 
 flattened head, 
 
 constricted neck, 
 
 short tail, and pit 
 
 in front of the eye 
 
 give unmistakable 
 
 evidence that the 
 
 reptile is a veno- 
 mous one. Two 
 
 fangs perforated or Ko . ^.. Bl!Mksu ^ tam (eet long . Photograpl , 
 
EEPTILIA 
 
 217 
 
 grooved are present in the front part of the upper jaw of 
 all venomous snakes. The red forked tongue darted 
 quickly back and forth is by many wrongly supposed to be 
 the sting of the snake. 
 
 The only venomous serpents of our country are the 
 rattlesnakes, copperhead pilot, cotton mouth or southern 
 moccasin, harlequin, and coral or bead snake. 
 
 The rattlesnakes, which are not found outside of America, 
 number about a 
 dozen species in the 
 United States. They 
 are characterized by 
 the possession of 
 from three to fifteen 
 horny buttons at 
 the end of the tail. 
 The number of these 
 buttons or rattles 
 does not tell the age 
 of the reptile, as two 
 or three are grown 
 in a year, while one 
 or more may be lost. 
 The poison lying in 
 a sac just below each eye passes out through a duct lead- 
 ing through the center of the fang. The bite is usually 
 fatal to man in from ten to fifteen hours, unless some 
 remedy is used. A deep gash should be made with a knife 
 so as to let the poisoned blood escape from the wound, 
 and if in an extremity a tight bandage should be placed 
 above it to prevent the poison from reaching the other 
 
 FIG. 250. Rattlesnake three feet long coiled ready 
 to strike. In this position it can dart its head for- 
 ward two feet only. Photograph. 
 
218 
 
 VERTEBRATA 
 
 parts of the system and paralyzing the nerves controlling 
 the heart and lungs. Wliiskey is useful to stimulate the 
 latter organs and a large quantity of milk should be drunk 
 
 FIG. 251. A, venomous snake (Copperhead) ; B, harmless snake. Photograph 
 natural size. 
 
 until vomiting occurs several times. In the mean time a 
 physician should be sent for to administer hypodermically 
 
 FIG. 252. Copperhead with mouth open and fangs erected as when biting. Photo- 
 graph natural size. 
 
 the proper antidotes, which are potassium permanganate 
 or chromic acid in the proportion of one part of the chem- 
 ical to one hundred parts of water. 
 The copperhead or pilot (Ancistrodon contortrix) is a 
 
REPTILIA 
 
 219 
 
 dangerous reptile found in the Eastern and Central States 
 in moist lands and near woodlands. The same treatment 
 
 FIG. 253. A copperhead three feet long. Photograph. 
 
 as that directed for the rattlesnake prevents the bite from 
 resulting fatally. 
 The southern water mocassin (Ancistrodon piscivorous) 
 
 FIG. 254. Ph 
 
 nty-foot python ill the Philadelphia Zoological 
 Gardens. 
 
220 
 
 VERTEBRATA 
 
 FIG. 265. Boa constrictor crushing a rat prepara- 
 tory to swallowing it. Photograph. 
 
 is a very venomous snake in the South, resting on bushes 
 overhanging streams watching for its favorite food, con- 
 sisting of frogs and 
 fish. The Cobra 
 ( Naja tripudians ) , 
 attaining a length of 
 four feet, is a deadly 
 snake living in India 
 where it is much 
 feared because dur- 
 ing the wet season 
 it seeks protection 
 in the huts of the 
 natives. About 
 twenty thousand people and several thousand cattle are 
 killed annually by 
 its bite. 
 
 The family Boidce 
 includes the largest 
 of living snakes. 
 They are non-veno- 
 mous but dangerous, 
 owing to their abil- 
 ity to crush a deer 
 or man by coiling 
 about him. A pecu- 
 liar feature exhibited 
 by them is the presence of rudimentary hind limbs. The 
 Indian python attains a length of twenty-five feet and a 
 diameter of ten inches. The Anaconda, inhabiting South 
 America, is the largest of all snakes. Specimens have 
 
 FIG. 256. Skull of Boa constrictor two thirds 
 natural size. Photograph. 
 
REPT1LIA 221 
 
 been seen more than thirty feet long. Among the true 
 Boas, found in Madagascar and tropical America, the best 
 known is the Boa constrictor of South America, about 
 thirteen feet in length. 
 
 The epidermis or outer skin of snakes is shed two or 
 three times a year and usually in a single piece. The 
 young of some species, such as the rattlesnake and moccasin, 
 are born alive, while others, such as the black snake, grass 
 snake, and milk snake, are hatched from eggs deposited 
 in the ground. Snakes pass the cold weather in a sleep- 
 ing state beneath rocks and logs or in holes in the ground. 
 
 Crocodilia 
 
 The crocodiles are represented by only two species in 
 this country: The Alligator Mississipiensis and Crocodilus 
 acutus floridanus. Both dwell in the lowlands of the South. 
 
 FIG. 257. Photograph of a young alligator four feet long in the Philadelphia 
 Zoological Gardens. 
 
 Their food consists largely of fish, but the larger alligators 
 from ten to fifteen feet long sometimes attack mammals, 
 dragging them into the water where they are drowned. 
 There are about twenty species of crocodiles and alligators 
 living in other countries. Some of them attain a length 
 of twenty feet and are dangerous to man. 
 
222 VERTEBRATA 
 
 The crocodilians reproduce by laying from thirty to 
 sixty oblong white eggs as large as those of a hen, in a 
 mound of muck, vegetable mold, or sand. Sufficient 
 heat to hatch them is furnished by the sun and the fer- 
 mentation in the decaying mound. The young of our 
 species are more than six inches long when born. 
 
 Chelonia or Testudinata: Tortoises and Turtles 
 
 The members of this order are characterized by a more 
 or less fully developed bony shell investing the body and 
 by the absence of teeth. 
 
 They are widely distributed throughout the warmer 
 regions of the globe, about fifty species being known in the 
 
 United States. 
 
 The name tortoise 
 is applied to those 
 forms having strong 
 legs with unwebbed 
 feet adapted to pro- 
 gression on land. 
 The commonest rep- 
 resentatives east of 
 the Rocky Moun- 
 tains are the box 
 tortoise ( Terrapene 
 
 FIG. 258. Box tortoise seen from beneath to show Carolina) and the 
 the hinge joint. One fifth natural size. Photo- Wf)od tOTtOlSB (Clem- 
 graph by D. S. Hartline. 
 
 mys insculpta). In 
 
 the box tortoise the dorsal shell, called carapace, is strongly 
 arched and of variable colors, blackish and yellowish. 
 
223 
 
 The ventral shell, the plastron, has a transverse hinge near 
 the middle. The wood tortoise has a keeled carapace, 
 the plates of which are marked with concentric striae 
 and radiating black bands. In the Gallapagos Islands 
 very large tortoises are found, one of which, the elephant 
 tortoise, attains a length of five feet and is able to carry a 
 man. 
 
 The term terrapin is used to designate those tortoises 
 having more or less of a web between the toes so that they 
 are adapted to both terrestrial and aquatic life. The 
 
 painted terrapin (Chry semis picta) is so called on account 
 of the bright red markings on the margins of the shell. 
 It is abundant everywhere along the ponds and streams 
 of the eastern United States. Large numbers sit on the 
 logs and the stones at the water's edge sunning them- 
 selves, and at the approach of any one glide into the 
 water. Several species of terrapins are much prized for 
 food. The snapping turtle (Chelydra serpentina), attaining 
 a length of two feet, is common throughout most of 
 North America. Soup made from it is greatly in demand. 
 It is a fierce carnivorous reptile feeding on ducks, chick- 
 ens, frogs, and other aquatic animals. 
 
224 VERTEBRATA 
 
 The true turtles differ from the tortoises in having limbs 
 flattened for swimming and only two of the toes bearing 
 claws. They dwell in the ocean and only come to shore 
 for the purpose of depositing their eggs in the sand to 
 
 FiQ. 260. Loggerhead turtle one week old. Photograph about natural size. 
 
 hatch. The green turtle is the source of the far-famed 
 turtle soup. The loggerhead turtle of Florida and the West 
 Indies resembles the green turtle, but is less prized for food. 
 The tortoise shell of commerce is derived from the hawk- 
 bill turtle (Chelone imbricata) which is more than two feet 
 in length. 
 
REPTILIA 225 
 
 All chelonians are similar in their habits and structure. 
 The eggs varying in number from five to more than one 
 hundred are deposited in the ground. They may be dis- 
 tinguished from those of snakes by the fact that they are 
 nearly spherical. The period during which the eggs are 
 incubated by the heat of the sun varies in different species 
 from one to four months. The land chelonians pass the 
 cold weather in a dormant state under logs and stones or 
 in self-constructed burrows in the earth, while the terra- 
 pins and turtles bury themselves in the mud. 
 
 Dinosauria : Giant Lizards 
 
 The Dinosauria form an order of extinct land reptiles 
 which inhabited the earth more than ten millions of vear? 
 
 FIG. 261. Dinosaur three feet long, restored from a study of the skeleton found to 
 Connecticut. 
 
 ago. All that is known of them has been learned from the 
 study of their fossil remains found in the rocks of Europe, 
 India, South Africa, and North America. All had limbs, 
 
226 VERTEBRATA 
 
 and in many species the hind ones were much larger than 
 the front ones, indicating that the animals walked on two 
 legs similar to the birds. The bones are hollow, as in birds, 
 and since in several other important features the skeleton 
 is similar to that of birds it is believed that the two groups 
 are closely related and have descended from a common 
 parent. Many species were of immense size. Bronto- 
 saurus, the giant reptile whose mounted stone skeleton is 
 in the Museum of Natural History in New York, was over 
 sixty feet long. Diplodocus, whose fossil remains may be 
 seen in the Carnegie Museum of Pittsburg, was about 
 seventy feet in length. The extinction of this entire group 
 of huge creatures may have been brought about by lack 
 of food or the presence of numerous parasitic or carnivor- 
 ous enemies. 
 
 The reptiles are intermediate in structure between the 
 amphibians and birds. The brain resembles that of the 
 frog, but the cerebrum is larger. The vascular and respira- 
 tory systems approach the condition in birds. In most 
 forms the heart has two auricles and one ventricle* but 
 in the crocodile a partition divides the ventricle into two 
 parts. 
 
 18. AVES 
 
 The birds are distinguished from all other vertebrates 
 by the presence of feathers. The two anterior limbs are 
 modified into the form of wings adapted for flying or swim- 
 ming. They differ from the three preceding classes in 
 being warm-blooded, having a temperature of from one 
 hundred and two to one hundred and nine degrees. As an 
 
AVES 
 
 227 
 
 assistance to flight most birds are able to decrease the 
 specific gravity of the body by means of a series of air sacs 
 communicating with the lungs. The larger sacs, usually 
 about a dozen hi number, lie in the trunk region, but smaller 
 ones sometimes occur in the bones, which are hollow in^ 
 stead of being filled with marrow 
 as in the mammals. All birds are 
 oviparous (lay eggs), some species 
 depositing as many as two hun- 
 dred eggs in a season, while others 
 lay only one each year. 
 
 No modern bird possesses any 
 teeth, but the fossil remains from 
 Kansas show that the birds living 
 millions of years ago had sharp, 
 reptile-like teeth. The most an- 
 cient bird known is Archceopteryx, 
 about the size of a crow. It pos- 
 sessed a long, jointed tail, numerous 
 sharp, conical teeth, claws on the 
 wing, and many other reptilian 
 characteristics. These facts indi- 
 cate that the birds have descended 
 from a reptile-like ancestor. 
 
 Within the history of man a number of species of Aves 
 have become extinct, and reports from nearly every state 
 show that unless quick and effective protection is afforded 
 our feathered friends, irreparable damage may result to 
 the country. Special investigations made by Hornaday 
 show that the average decrease in bird life throughout the 
 United States from 1883-1898 was forty-six per cent. 
 
 FIG. 262. Diagram of the 
 lungs and air sacs of a pig- 
 eon, p, air sacs ; lu, lung ; 
 t, trachea. 
 
228 VERTEBRATA 
 
 Reports from Maine, Rhode Island, Pennsylvania, Indiana, 
 North Dakota, Georgia, Louisiana, and Texas stated that 
 more than half their birds had disappeared, while observers 
 from Connecticut, Florida, and Montana agreed that the 
 numbers of birds in those states had decreased by seventy- 
 five per cent. The seriousness of these facts becomes 
 apparent only when we realize that recent investigations 
 have shown that there is as much truth as poetry in the 
 lines of Longfellow 
 
 "The summer came and all the birds were dead; 
 The days were like hot coals; the very ground 
 Was burned to ashes ; in the orchards fed 
 Myriads of caterpillars, and around 
 The cultivated fields and garden beds 
 Hosts of devouring insects crawled, and found 
 No foe to check their march till they had made 
 The land a desert without leaf or shade." 
 
 A careful study of the birds emphasizes the necessity of 
 making children familiar with their value, not only from 
 an economic standpoint, but also from an aesthetic view. 
 With the exception of the English sparrow, the cow bird, 
 two species of hawks, and the great horned owl, all birds 
 of our country are man's friends. 
 
 There are about thirteen thousand species of birds in 
 the world, but not more than eight hundred species occur 
 in the United States, and seldom is any one locality favored 
 with more than two hundred kinds. But few lovers of 
 nature can expect to become familiar with more than fifty 
 species in one region. The identification of birds, espe- 
 cially the warblers, vireos, and sparrows, in the bush or on 
 the wing, is not an easy task, but if the beginner proceeds 
 
229 
 
 patiently and systematically he will be able to acquaint 
 himself with a score or more of birds during any summer 
 month. When a new bird is seen, the observer should 
 write an accurate description of it in his notebook, giving 
 the length from the tip of the bill to the end of the tail; 
 the color of the crown and sides of the head, back, wings, 
 tail, breast, and belly; length, shape, and color of the bill; 
 
 Occiput Forehead 
 x -Lores 
 
 Upper Ma n dible 
 
 werMandible 
 
 Lateral Hectn 
 iMiddle 
 
 Rectrices ^ \ 
 
 (Hallux) 
 
 IjinerToe 
 Middle Toe 
 
 Outer Toe 
 FIG. 263. Names used in describing a bird. Drawing by Reese. 
 
 length, position, and arrangement of the tail feathers; and 
 the method of feeding and manner of flight as well as its 
 characteristic song. Such a record will enable one to 
 identify the stranger by comparison with the descriptions 
 given in such books as " Bird Neighbors " or Chapman's 
 " Bird Life." The brief descriptions and illustrations in 
 the following pages will help the pupil to determine the 
 names of some species. 
 
230 
 
 VERTEBRATA 
 
 FIG. 264. Kingbird at its nest. Photographed in the Museum of Natural History, 
 New York. One third natural size. 
 
AVES 
 
 231 
 
 The birds are grouped into about twenty orders, of 
 which only the eight most important ones will be dis- 
 cussed. 
 
 Passeres : Perching Birds 
 
 This order includes approximately one half of our species. 
 They may be recognized by the presence of four un webbed 
 toes all on the same level and with joints in number 2, 3, 
 4, 5, respectively from the first (inner) toe to the fourth 
 (hind). All our song birds belong to this group, of which 
 the families here given have representatives in most local- 
 ities. 
 
 Flycatchers (Tyrannidae) . The members of this family 
 
 FIG. 265. Phoebe with its mud nest in the corner of an old boathouse. Photo- 
 graphed in the Academy of Natural Sciences, Philadelphia. One third natural 
 size. 
 
 are so named because they feed largely on aerial insects 
 which they seize in flight. Hornaday says every flycatcher 
 
232 
 
 VERTEBRATA 
 
 -Hunting crows' eggs in March. 
 Photograph by Neal. 
 
 is worth double its 
 weight in silver to 
 the farmers. The 
 kingbird or bee mar- 
 tin, recognized by its 
 white-tipped black 
 tail, was once thought 
 to be a destroyer of 
 bees, but late inves- 
 tigations show that 
 it eats very few bees 
 and most of these are 
 drones. Ninety per 
 cent of its food con- 
 sists of harmful in- 
 sects. It nests in 
 trees in the orchard 
 or forest margin. It 
 migrates south in 
 winter. The Phoebe 
 or pewee is a trifle 
 larger than the Eng- 
 lish sparrow and re- 
 veals its presence by 
 its characteristic note, 
 pewit, pewee, phcebe, 
 phoabe. It arrives 
 from the south in 
 March, and acts as 
 special police to the 
 agricultural interests 
 
AVES 
 
 233 
 
 . 267. Crow and nest, one tenth natural size. Photographed in the Academy 
 of Natural Sciences, Philadelphia^ 
 
234 
 
 VERTEBRATA 
 
285 
 
 throughout the summer, when more than nine tenths of 
 its food consists of insects and spiders. 
 
 Crows (Corvidae). The crows, jays, and ravens are not 
 worthy of much encouragement. The common crow, 
 although destroying young corn and eating the eggs and 
 the young of other birds, atones for his evil deeds by 
 destroying large numbers of mice and cutworms. The 
 magpie west of the Rocky Mountains sometimes attacks 
 horses and mules where the flesh has been lacerated by 
 the harness. 
 
 Orioles and Blackbirds (Icteridae). The Baltimore 
 oriole often called golden robin or firebird should be familiar 
 to every one in eastern North America. The male arriving 
 from the south when the orchards are in blossom may be 
 recognized by its glossy black head, throat, wings, and 
 upper back, and the rich orange color of the other portions 
 of the body. It is a trifle smaller and not so stout as the 
 common robin. The female is of a yellowish olive color. 
 The nest is an exquisitely woven pouch swung from a high 
 limb. 
 
 The five or six young during their ten days of life 
 in the nest consume thousands of noxious caterpillars and 
 canker worms, of which species the parents are also fond. 
 Beal states that caterpillars formed thirty-four per cent of 
 the food of one hundred and thirteen specimens examined. 
 
 The bobolink, a country dweller in eastern North America 
 all summer, assists the farmer in destroying insects, but 
 later in the season retiring southward it creates havoc in 
 the rice fields and is known as the rice bird. When sold 
 in the market it is called reed bird. This species is an ex- 
 emplification of the great difference that may exist between 
 
236 VERTEBRATA 
 
 the plumage of the two sexes as well as the variation in 
 the plumage in different seasons. The black and white 
 male presents a strong contrast to the dull yellowish-brown 
 female. In autumn, however, the plumage of the male 
 changes to the same hue as that of his partner. 
 
 The cow bird never builds a nest, but lays its brown- 
 speckled white eggs in the nest of a smaller bird where 
 hatching more quickly and growing more rapidly than the 
 rightful occupants, they crowed the latter out of the nest, 
 It is nearly as large as the robin, but not so stout. The 
 dusky brown female is smaller than the male which has 
 an iridescent black head. They often mingle with the 
 cows in the pasture. 
 
 The mead.ow lark, widely distributed over the United 
 States, is a lover of the pastures and meadows, where it 
 may be recognized by its white tail feathers and large 
 black crescent on a yellow breast. It is larger than the 
 robin. The stomach contents of ninety-three specimens 
 show that it is of great value in ridding the grass lands of 
 insects. The blackbirds, the larger of which are called 
 grackles, sometimes pull up the young corn, but they make 
 ample restitution by destroying weevils, grubs, and army 
 worms. The red-winged blackbirds nest in bushes in the 
 swamps, and the grackles build in the tree tops. 
 
 Finches (Fringillidae). This family includes many 
 small birds and a few larger ones, among which is the rose- 
 breasted grosbeak, famous for its soft, sweet, rolling warble 
 on moonlight nights. The large beak and the rosy breast 
 of the male gave origin to the name. 
 
 The sparrows, of which there are more than a score of 
 species residing with us, are with one exception exceedingly 
 
AVES 
 
 237 
 
 FIG. 2C9. Rose-breasted grosbeak. Female on the left and male on the right. 
 Photograph one fourth natural size. 
 
 beneficial birds, consuming large quantities of noxious 
 
 weed seeds and destructive insects. 
 
 The English sparrow (Passer domesticus) was imported 
 from England into this coun- 
 try in 1850, and as it rears 
 four or five broods of from 
 four to six young each season, 
 the whole country has become 
 infested with the species. The 
 male is easily recognized by 
 its black throat and breast. 
 In many localities this is the 
 only sparrow seen in winter. 
 It destroys not only buds and 
 blossoms but attacks grapes, 
 berries, tomatoes, and other 
 FIG. 270. Male English sparrow. fruits, in addition to consum- 
 
238 
 
 VERTEBRATA 
 
 ing large quantities of grain and being guilty of driving 
 away the song birds, whose nests it robs. An examination 
 of five hundred and twenty-two stomachs made by the 
 Department of Agriculture showed that over three fourths 
 of the birds had eaten no insects whatever, while the others 
 
 FIG. 271. Eggs of the English sparrow showing variation in color. Photograph 
 natural size. 
 
 had devoured but few insects, most of which were beneficial 
 ones. The nests, untidily built of hay, stems, and feathers, 
 in clinging vines and trees, should be destroyed. 
 
 The chipping sparrow, called chippy or hair bird, is dis- 
 tinguished from the English sparrow by a gray stripe over 
 the eye and a blackish -brown one apparently through it. 
 The value of this bird, rearing two broods each season, is 
 shown by Weed and Dearborn, who watched the parent 
 birds come to the nest almost two hundred times in one day, 
 
AVES 
 
 239 
 
 Fio. 272. Nest of a song sparrow in a currant bush. Photograph half natural 
 size. 
 
 bringing caterpillars, grasshoppers, and Other insects for 
 the young. Forty per cent of the food of the adult con- 
 sists of insects. The song sparrow differs from the two 
 preceding in having the ventral portion of the body gray 
 shading to white and heavily streaked with darkest brown. 
 The vesper sparrow is easily identified by the partially 
 white outer tail quills very conspicuous in flight. Its nest 
 
240 
 
 VERTEBRATA 
 
 FIG. 273. Song sparrow. 
 
 is built on the ground but not 
 lined with hair like the song 
 sparrow's, which sometimes is 
 found in a bush. 
 
 Swallows (Hirundinidae). 
 The swallows are character- 
 ized by a forked tail. They 
 are valuable insectivorous 
 birds, seizing their food on 
 the wing. The cliff swallows 
 and barn swallows are the 
 commonest summer species 
 in eastern United States. 
 The bank swallow rears its 
 young in holes excavated to 
 the depth of two feet in a sand bank. 
 
 The Chatterers (Ampelidse). This family is well repre- 
 sented by the cedar bird, famous for its raids on insects. 
 Seven stomachs examined averaged over one hundred 
 canker worms each. 
 
 The Vireos (Vireonidae). The vireos are olivaceous 
 birds, more slender than the English sparrow. The red- 
 eyed and white-eyed are common. The nest is easily recog- 
 nized by the fact that it has the shape of the lower half 
 of a teacup and is constructed in the crotch of a small 
 horizontal limb without any support underneath. During 
 the locust pest in Nebraska four fifths of the food of the 
 red-eyed vireo consisted of these insects. 
 
 Wrens and Mocking Birds (Troglodytidae). The cat- 
 bird and house wren are the best known members of this 
 family. The latter is the most valuable of all birds in 
 
AVES 
 
 241 
 
 FIG. 274. Nest of a chipping sparrow on the ground in a wheat field. Photo- 
 graph two thirds natural size. 
 
 destroying insects, and should be coaxed about our yards 
 by nailing up boxes in which it may nest. The entrance 
 to a box must not be more than an inch in diameter, as 
 otherwise the English sparrow would preempt the home. 
 A study of fifty-two wrens showed that ninety-eight per 
 cent of their food was of insects. 
 
 Nuthatches and Titmouse (Paridae). This is one of the 
 few families of birds remaining in middle and northern 
 
242 
 
 VERTEBRATA 
 
 FIG. 276. Red-eyed vireo. 
 Photograph one half life 
 size. 
 
 Fm. 275. Cedar bird one third life size. 
 Photographed in Academy of Natural Sci- 
 ences. 
 
 United States throughout the 
 winter. The white-breasted nut- 
 hatch seeks its food running up 
 and down the trees in summer 
 and feeds on seeds in winter. The black-capped chick- 
 adee or titmouse may be identified by its black crown 
 and throat. According to recent investigations if we 
 could persuade enough of these birds to dwell with us, 
 the plant lice pest, costing millions of dollars annually, 
 would be at an end. Over five thousand eggs of plant 
 lice have been found in the stomach of one chickadee. 
 Eggs of other injurious insects, as well as the adults, are 
 also eaten in large numbers. 
 
 Thrushes (Turdidae). The robin is by many wrong- 
 fully considered a harmful bird on account of the cherries 
 
AVES 
 
 243 
 
 and berries taken. The large number of cutworms, grass- 
 
 hoppers, and beetles eaten more than compensates for the 
 
 little fruit taken. _ __ __ i 
 
 Six robins shot in 
 
 Nebraska contained 
 
 two hundred and 
 
 sixty-five Rocky 
 
 Mountain locusts 
 
 and eighty-four 
 
 other insects. 
 
 The wood thrush 
 (Turdus mustelinus) 
 adds much to the 
 charm of the wood- 
 lands in eastern 
 United States by the 
 melody of its liquid, 
 flute-like note. It 
 remains in the North 
 during the summer 
 only, while its relative, the bluebird, a voracious insect 
 eater, dwells throughout the year in the latitude of New 
 York and southward. Meat bones hung in the trees 
 in winter and small boxes with inch and a quarter 
 entrances nailed up ten feet above the ground for 
 homes in summer will do much toward attracting this 
 valuable and beautiful blue-backed gem about the yard. 
 
 It is estimated that a brood of five young during their 
 thirteen days of home life will consume over one thou- 
 sand harmful insects, and more than half of the parents' 
 food consists of these injurious creatures. 
 
 m ' ~ Nest of s ^ tograph ne fourth 
 
244 
 
 VERTEBRATA 
 
 FIG. 278. Catbirds and nest. Photographed in the Academy of Natural Sciences, 
 Philadelphia. 
 
 Humming Birds and Swifts (Macrochires) 
 
 This order includes the smallest of birds and also a few 
 larger species. The most notable member is the ruby- 
 throated humming-bird feeding on the nectar of flowers, sap 
 of trees, and insects. The chimney swift, building its nest 
 of sticks glued together with saliva, and fixed to the chim- 
 
AVES 
 
 245 
 
 ney or inside of 
 deserted build- 
 ings, seizes its in- 
 sect food in flight, 
 as do also th e whip- 
 poor-will and 
 nighlhawk, com- 
 ing forth at even- 
 tide from their 
 forest retreats. 
 
 Woodpeckers 
 
 (Pici) 
 
 FIG. 279. Wren with food for her young. Photo- 
 graphed in the Academy of Natural Sciences. One 
 third life size. 
 
 This order is 
 composed of ar- 
 boreal birds, all of which with one exception, the sapsucker, 
 
 are preeminently 
 insectivorous birds. 
 They may be rec- 
 ognized by their 
 habits of picking 
 small holes in the 
 bark of trees to se- 
 cure the bark bee- 
 tles and larvae of 
 other injurious 
 beetles which dam- 
 age the forest trees 
 to the extent of 
 several millions of 
 dollars annually. 
 
 Fl. 280. White-breasted nuthatch photographed in the rp, j - ,, 
 
 Academy of Natural Sciences. One third life size. IHC largest 01 the 
 
246 
 
 VERTEBRATA 
 
 woodpeckers common near civilization is the flicker or 
 high-holer, also called yellow-hammer, easily distinguished 
 by the black crescent on the breast and the white rump 
 conspicuous in flight. It feeds largely on ants. The 
 
 FIG. 281. . 
 
 FIG. 281. 
 
 FIG. 281. C. 
 
 FIG. 281. D. 
 
 FIG. 281. The robin demonstrating how quickly hated insects may be transformed 
 into grace and beauty. A and J3, May first ; C, May ninth ; D, May fourteenth ; 
 E (page 247), May seventeenth, the day on which they flew away. Photograph 
 by N. F. Davis. 
 
AVES 
 
 247 
 
 FIG. 281'. E. 
 
 hairy woodpecker and the 
 downy woodpecker, very sim- 
 ilar in appearance, are the 
 ones seen about lawns and 
 parks. The red-headed 
 woodpecker nesting in the 
 hollow of telegraph poles 
 and trees is common in 
 many regions. 
 
 Cuckoos (Coccyges) 
 
 This order is represented 
 throughout eastern North America by the black-billed 
 and yellow-billed cuckoos, sometimes called rain crows. 
 
 They are valuable 
 summer residents 
 among the shrub- 
 bery and in the 
 orchards and 
 woods where they 
 devour great quan- 
 tities of hairy cat- 
 erpillars and other 
 insects. During 
 May and June, tent 
 caterpillars consti- 
 tute about half 
 their fare. The 
 belted kingfisher, 
 common in most 
 
 FIG. 282. The wood thrush at her nest. One fifth 
 
 life size. Photograph by N. F, Davis. parts OI Olir COUU- 
 
248 
 
 VERTEBRATA 
 
 try, is one of the few birds living on fish. It nests in 
 deep holes at the water's edge. 
 
 Hawks, Owls, and Eagles (Raptores) 
 
 The members of this order are called birds of prey, 
 although many of them feed largely on insects and 
 are therefore beneficial. They are characterized by a 
 
 FIG. 283. Young bluebird two weeks old just ready to fly. Two broods are 
 batched yearly in the cavity of this old fence post. Photograph one sixth life size. 
 
AVES 
 
 249 
 
 FIG. 284. Ruby-throated humming bird on its nest. 
 Photographed in the Academy of Natural Sciences, 
 Philadelphia. Half life size. 
 
 strongly hooked bill 
 
 and curved claws, 
 
 called talons, adapted 
 
 for seizing and tear- 
 ing flesh. Some of 
 
 them are of large 
 
 size, such as the 
 
 condor of South 
 
 America and the 
 
 California vulture, 
 
 which are the largest 
 
 birds of flight in the 
 
 world. 
 
 Hawks and Eagles 
 
 (Falconidae) . 
 
 Twenty years ago 
 
 the hawks were thought to be man's enemies, and bounties 
 
 were offered in some states for their scalps, resulting in 
 
 the paying out of 
 many thousands 
 of dollars for the 
 killing of birds 
 protecting the 
 agricultural inter- 
 ests, upon which 
 the success of the 
 nation depends. 
 They feed largely 
 on rats, mice, and 
 other destructive 
 creatures. Owing 
 
 FIG. 285. Chimney swift photographed from life. 
 One third natural size. 
 
VEKTEBRATA 
 
 FIG. 286. Nest of a chimney swift built in a barn. Photograph one third 
 natural size. 
 
 FlG. 287. Flickers ready for their first flight. The hole is the door to their home 
 Qne tenth life size. Photographed by Jessie Wells. 
 
AVES 
 
 251 
 
 to information lately furnished the lawmakers by the 
 zoologists, laws have been passed in many states protect- 
 ing all hawks except the goshawk, Cooper's hawk, and the 
 sharp-shinned hawk, which feed largely on song birds and 
 poultry. The sparrow hawk occasionally destroys a few 
 
 FlG. 288. Black-billed cuckoo. Photograph one third life size. 
 
 song birds, but atones for it by preying on the worth- 
 less English sparrows and grasshoppers. Of one hundred 
 and seventy stomachs of the red-tailed hawk examined, 
 one hundred and thirty-one contained mice, nine contained 
 rabbits and squirrels, six had snakes and insects, and in 
 only four was any poultry present; nevertheless, this val- 
 uable bird is popularly referred to as the hen hawk. 
 
252 VERTEBRATA 
 
 Only two species of eagles dwell in our land. The bald 
 eagle, after attaining the age of three years, is distinguished 
 from the golden eagle by its white-feathered head to which 
 the name is due. The golden eagle has been known to 
 destroy lambs and young deer, but the bald eagle is less 
 fierce, and neither has ever been known to attack children. 
 
 Owls (Bubonidse). This family includes all the owls of 
 
 FIG. 289. Foot of great horned owl. Photograph half natural size. 
 
 North America except the barn owl. With few exceptions 
 they are nocturnal birds, living largely on mice, gophers, 
 frogs, snakes, and rabbits. They have a strange habit of 
 regurgitating out of the mouth in the form of small pellets 
 such indigestible portions of the food as hair and bones. 
 An examination of these pellets shows the kinds of animals 
 upon which the bird has fed. It has thus been found that 
 all of the owls with the exception of the great horned owl 
 
AVES 
 
 253 
 
 are beneficial to the farmer. The screech owl and the 
 long-eared owl, so called on account of the tuft of feathers 
 near each ear, are widely distributed over the United 
 
 FIG. 290. Cooper's hawk or chicken hawk eighteen inches long. Photograph of 
 a mount by Neal of Easton. 
 
 States. Pellets from four of the latter species showed that 
 in fifty-nine days they had consumed three hundred and 
 forty-six mice, which if left unmolested would have con- 
 sumed many dollars' worth of the farmers' produce. 
 The order Gallince, including the much prized game birds, 
 
254 
 
 VERTEBBATA 
 
 partridge, grouse, and turkey, and the order Columbce, com- 
 posed of the doves, will not be discussed, as their repre- 
 sentatives are scarce in most localities. 
 
 The Herons (Herodiones) 
 
 This order includes the herons, storks, and ibises, which 
 have long necks and long legs for wading. They are shore- 
 
 FlO. 291. Sharp-shinned hawk one foot long. Photograph of a mount 
 by Neal. 
 
 loving birds feeding upon frogs and fish. The great blue 
 heron, wrongly called crane, is common in eastern North 
 America, where it may be seen wading about in the meadows 
 and swamps. In nesting, the herons usually form societies, 
 so that in the space of two or three acres one may count in 
 
AVES 
 
 255 
 
 the trees more than a hundred nests. The little blue heron 
 visits the creeks east of the Mississippi River. The snowy 
 heron or snowy egret is the most beautiful bird in the world. 
 Its head and back bear 
 numerous filmy plumes 
 which are so much sought 
 after to adorn the head 
 gear of women that the 
 species once so abundant 
 in Florida is now almost 
 exterminated. A law has 
 lately been passed pre- 
 venting the sale of these 
 plumes known as aigrettes. 
 That some effective means 
 to stop the use of song bird 
 plumage in millinery work 
 should be devised is evi- 
 dent when we consider the 
 number of birds annually 
 sacrificed on the altar of 
 woman's vanity. Forest 
 and Stream mentions a 
 dealer who in three months 
 supplied over eleven thou- 
 sand skins for the milliners, and the same person is said 
 to handle thirty thousand birdskins every year. A single 
 foreign order given a New York milliner called for the 
 death of over forty thousand of our beautiful birds, which 
 were sold at ten cents each. During four months seventy 
 thousand birdskins were sent from one Long Island vil- 
 
 FIG. 292- Sparrow hawk ten inches 
 long. Photograph from life. 
 
256 
 
 VERTEBBATA 
 
 FlG. 293. Red-sliouldered hawk at her nest in the tree top. Photographed in the 
 Academy of Natural Sciences, Philadelphia. One eighth life size. 
 
 lage to supply the peacock populace of New York. The 
 Audubon Society has proved itself a mighty force for good 
 not only in showing the evil wrought by collectors of birds 
 and their eggs, but also in rendering unpopular the use of 
 birds for millinery purposes. If every pupil will do his part 
 in that great missionary work of protecting the birds, their 
 nests, and young, in the coming years the dream of Shelley 
 may be nearer realization. 
 
AYES 
 
 25? 
 
 ' { No longer now the winged habitants 
 That in the woods their sweet lives sing away 
 Flee from the form of man ; but gather round, 
 And prune their sunny feathers on the hands 
 Which little children stretch in friendly sport 
 Toward these dreadless partners of their play. 
 
 . . . Happiness 
 And science dawn, though late, upon earth." 
 
 FIG. 294. Our national bird, the bald eagle. Photograph 
 of a mount by Neal. One sixth life size. 
 
258 
 
 VERTEBRATA 
 
 That birds limit in a large degree the outbreaks of injuri- 
 ous animals is shown by recent reports. An apple orchard 
 in Illinois was severely attacked by canker worms (Fig. 88) 
 and numerous species of birds came to feed on the pests. 
 Several individuals of each of thirty-six different species 
 were killed and the stomach contents examined by Pro- 
 
 FiG. 295. A, Screech owl. Photograph from life. One fifth natural size. 
 M, Long-eared owl. 
 
 fessor Forbes. Canker worms made up twenty per cent of 
 the food of the robins, fifteen per cent of the food of cat- 
 birds, two thirds of the food of the warblers, forty per 
 cent of the food of the vireos, fifty-nine per cent of the 
 food of the indigo bunting, sixty-one per cent of the food 
 of the chickadees, seventy-five per cent of the food of the 
 black-billed cuckoos, and practically all of the food of 
 the cedar birds. 
 
AVES 
 
 259 
 
 Similar striking facts are shown by Aughey's investiga- 
 tion during the outbreak of the Rocky Mountain locust, 
 when in a single year, 1874, they destroyed forty-five mil- 
 lions of dollars' worth of crops. For one meal, six robins 
 had eaten two hundred and sixty-five locusts; five catbirds, 
 
 FIG. 296. A friend of the birds. 
 
 one hundred and fifty-two; three bluebirds, sixty-seven; 
 nine chickadees, four hundred and eighty-one; twenty 
 swallows, five hundred and sixty-five: and eight flickers, 
 two hundred and fifty-two. Every species, of which there 
 were fifty present in that region, fed on the pests. Out- 
 breaks of army worms and field mice have also been checked 
 by the birds in a similar manner. 
 
 The pupils of every school should determine whether 
 the number of birds is increasing or decreasing from year 
 
260 VERTEBRATA 
 
 to year. An excellent method of determining this is to 
 count the nests to be seen in the trees as soon as the leaves 
 have fallen. Robins and some other birds use the same 
 nest for two or even three broods in one year, but on an 
 average it is safe to count only five birds reared from each 
 nest. Small boys and cats are the greatest enemies of 
 young birds near towns and cities. 
 
 The migration of birds is worthy of the attention of every 
 one. In the latitude of New York, the chief birds remain- 
 ing with us throughout the year are the owls, crows, wood- 
 peckers, cedar birds, song sparrow, English sparrow, 
 black-capped chickadee, and bluebird. Some of these 
 frequently go south during severe cold weather. The 
 other summer residents pass the winter in the South, 
 some, like the bobolinks, going as far as Brazil. 
 
 In many cases the migration trips are made by night 
 and often at a great height. The purple martin, the 
 kingbird, the swallows, and the orioles depart in September, 
 and the majority begin their southern journey in October; 
 but the bluebird, robin, and chipping sparrow remain 
 until November and return as early as March. The 
 latest comers in spring are the wood thrush, vireos, orioles, 
 bobolinks, and cuckoos, which arrive in May. The cause 
 of bird migration is not known. Cold weather may seem 
 to force them south, but why do they leave the warm 
 tropical regions abounding in food in the spring and come 
 to the bleak north? 
 
 The regions to which some of our species go for winter- 
 ing are quite definitely mapped out. The robins that 
 spend the summer in Canada have for their winter resi- 
 dence portions of the United States in the latitude of 
 
MAMMALIA 261 
 
 Washington, while the robins summering in northern 
 United States migrate to a winter home along the Gulf of 
 Mexico. The nighthawks, living in Alaska from May to 
 September, fly over five thousand miles to their congenial 
 winter home in Patagonia. Over fifty species of New 
 England birds winter in South America. Twenty-five 
 species from northern United States pass the winter in 
 Porto Rico, an equal number go to Cuba, and at least 
 twenty species remain during our cold season, in Jamaica. 
 Others, such as the red-eyed vireo, migrate to Central 
 America. 
 
 Every school should keep a record of the time of the 
 appearance of each species in the spring and its departure 
 in the autumn. The pupils should be encouraged to 
 report how many birds they have coaxed to dwell in the 
 yard and garden by putting out meat bones and bread 
 crumbs in winter, and erecting nesting boxes for summer. 
 
 19. MAMMALIA 
 
 The mammals are distinguished from all other verte- 
 brates by their habit of providing the young with milk 
 and by the possession usually of a hairy covering. Like 
 the birds they are distributed throughout both the warm 
 and cold regions of both hemispheres. Since the habits as 
 well as the structure of the different groups vary widely 
 it will be necessary to consider the characteristics of each 
 of the eleven orders. 
 
 Egg layers (Monotremata). The duck mole of Aus- 
 tralia is one of the three species of mammals which lay 
 eggs. It deposits hi its burrow on the bank of a stream 
 
262 VERTEBRATA 
 
 FIG. 297. The duck mole or duck bill. Photograph one fourth natural size. 
 
 two eggs about as large as those of a robin. The Echidnas, 
 of which there are two species, inhabit Australia and New 
 Guinea. The single egg deposited is placed in the abclomi- 
 
 FIG. 298. Kangaroos. Thejone at the left shows the opening to the pouch. 
 
MAMMALIA 
 
 263 
 
 nal pouch where the young one, soon hatching, is carried 
 for some weeks. 
 
 Pouched Mammals (Marsupialia or Didelphia). The 
 marsupials, though 
 not oviparous , ap- 
 proach that condi- 
 tion inasmuch as the 
 young are born in a 
 very immature condi- 
 tion and in most cases 
 are carried in the 
 pouch by the female 
 several weeks. The 
 largest species of the 
 kangaroos dwelling in Australia is the boomer, standing four 
 feet high and capable of clearing twenty feet at a single 
 bound. The opossums are the only marsupials living in 
 North America. The one representative in the United 
 
 FIG. 299. Virginia opossum. Photograph by 
 N. F. Davis. One eighth life size. 
 
 FIG. 300. The spiny ant-eater (Kchidna). Photograph one fourth life size. 
 
264 VERTEBRATA 
 
 States is the Virginia opossum found in nearly every 
 state. The young varying in number from six to twelve 
 are naked, blind, and about half an inch long at birth, 
 when the mother by means of her fore paws places them 
 in her pouch. Here they remain several weeks constantly 
 attached to the teats through which the mother pumps 
 the milk into their mouths. 
 
 Ant-eaters (Edentata). This order is so named be- 
 cause some of the species have no teeth. The armadillos, 
 remarkable for their covering of bony plates, inhabit 
 South America and southern North America, while the 
 ant-eaters dwell in South America, Asia, and Africa. 
 The Sloths live in South America only. 
 
 Sea cows (Sirenia). The members of this order are 
 characterized by the absence of hind limbs and the pres- 
 ence of paddle-like fore limbs adapted for an aquatic life. 
 The manatee is the only representative in our country. 
 It swims in the rivers of Florida. The fact that the flipper- 
 like fore limbs contain the same bones present in the ter- 
 restrial mammals, indicates that the ancestors of the 
 Sirenia were land mammals. 
 
 Whales, Dolphins, and Porpoises (Cetacea). These, like 
 the Sirenia, are entirely aquatic, and with few exceptions 
 live in salt water only. They are characterized by the 
 absence of hair and hind limbs, though in some species 
 rudiments of the latter are found beneath the skin, indi- 
 cating that the whales have descended from land animals 
 with two pairs of limbs. The toothless, or baleen whales, 
 are valuable both for oil and whalebone. The largest 
 species, the sulphur-bottom whale of the Pacific, attains a 
 length of ninety-five feet, One individual will yield three 
 
MAMMALIA 
 
 265 
 
 hundred barrels of oil and two tons of whalebone, The 
 toothed or sperm whales inhabit both the great oceans. 
 The dolphins occur in schools and 
 dart out and in the water at fre- 
 quent intervals. The common At- 
 lantic porpoise is the puffer seen 
 rolling in the breakers near the 
 shore. 
 
 Hoofed Mammals (Ungulata). 
 The members of this order are nota- 
 ble for the variation in the number 
 of digits (toes or ringers) from one 
 to five. The horses are one-toed; 
 the cattle and deer, two-toed; the 
 pigs, four-toed; and the elephant, 
 five-toed. This condition is ex- 
 plained by the theory of evolution, 
 declaring that all ungulates origi- 
 nally had five digits to each limb, 
 but in some cases one or more has 
 been lost because they were not of 
 advantage to the species. The an- 
 cestors of the horse known by fossil 
 remains exhibit four complete toes, 
 and the most ancient mammals, liv- 
 ing several millions of years ago, all 
 had five toes on each limb. Rudi- 
 ments of these lost digits are present 
 in the horse, deer, and cow. The digits are numbered 
 from the inside outward, i.e., from the thumb toward the 
 little finger. The horse walks on the end of the third 
 
 FIG. 301. Skeleton of a 
 liorsc that lived in Colo- 
 rado more than a million of 
 years ago. From Guide 
 Leaflet of the American 
 Museum by Matthews. 
 
266 
 
 VERTEBRATA 
 
 digit, so that the wrist and ankle, often wrongly called 
 the knee, are more than a foot above the ground, while 
 the real knee is close up to the body. Animals walking 
 on the ends of their toes are said to be digitigrade, in 
 
 PlG. 302. -~ Skeleton of the horse, a, rudiment of the fourth digit (splint bone) 
 about half as long as the third ; rf, second digit ; e, ankle ; w t wrist ; n, knee ; 
 m, femur ; /, forearm with large radius and rudimentary ulna ; h, humerus. 
 
 distinction to those walking on the flat of the foot, called 
 plantigrade. 
 
 The cattle family (Bovidce] includes the goats, sheep, and 
 cows, among the most celebrated of which are the American 
 bison (buffalo) now nearly extinct, and the Rocky Moun- 
 tain goat able to walk on almost perpendicular cliffs. 
 
MAMMALIA 
 
 267 
 
 The deer family (Cervidce) is well represented on all the 
 continents except Africa. With the exception of the 
 caribou only the males of the deer possess antlers, and they 
 are always shed annually, and usually in February or March. 
 A new growth be- 
 gins at once and 
 continues so rap- 
 idly that antlers 
 like those of the 
 elk measuring four 
 feet are renewed 
 in less than four 
 months. The elk, 
 the largest species 
 of the round- 
 horned deer, 
 abounds in the 
 
 vicinitv Of the Yel- FIG. 30S. Kocky Mountain goat. Photographed 
 Ui y in the Philadelphia Zoological Gardens. 
 
 lowstone Park. 
 
 The Virginia deer, also called white-tailed deer, inhabits 
 every state in the Union except Delaware, Oregon, Nevada, 
 California, and Arizona, but is most abundant in the 
 Adirondacks, Maine, Vermont, and Michigan. 
 
 The moose, the largest species of the deer family, reaches 
 a height of nine feet. The overhanging nose, high-humped 
 shoulders, and huge flat antlers of the male distinguish it 
 from the other deer. It is found in northern United 
 States, Canada, and Alaska. The caribou or reindeer, both 
 sexes of which bear slightly flattened antlers, occupy the 
 upper half of the continents of North America and Eurasia, 
 where they feed upon moss and lichens. The domestic 
 
268 VERTEBRATA 
 
 reindeer (Rangifer tarandus) is a native of Siberia whence 
 over fifteen hundred animals have been imported into 
 Alaska since 1892, and they have multiplied to the number 
 of several thousand. During the last few years the United 
 States Government has granted annually twenty-five 
 
 FIG. 304. Skull of a deer with the lower jaw removed. The burr at the base of 
 the antler shows where it separates. The absence of upper incisors and 
 canine teeth is characteristic of ruminants (cud chewers). 
 
 thousand dollars for the purpose of making the reindeer 
 a permanent resource for food and domestic service among 
 the Eskimos. 
 
 The camel of Africa, the 'llama of South America, and 
 the elephant of Africa and Asia have been trained to render 
 valuable service to man . The water sacs, which are numer- 
 
MAMMALIA 269 
 
 ous pouches on the wall of the stomach, enable the camel 
 to go many hours without water in the sandy Sahara. The 
 tusks of the elephant are the two upper overgrown incisor 
 
 FIG. 305. Wapiti or American elk. Photographed in the Philadelphia Zoological 
 Gardens. 
 
 teeth composed almost entirely of dentine, which furnishes 
 the ivory of commerce. 
 
 Gnawers (Rodentia). Any one of the four hundred 
 species of rodents living in America may be recognized by 
 the large chisel-shaped incisor teeth, of which there are two 
 in the lower jaw and either two or four in the upper one, 
 while the canine teeth are wanting (Fig. 309). 
 
270 
 
 VERTEBRATA 
 
 The squirrels (Sciuridce) are represented by the chip- 
 munks or ground-squirrels, usually striped, the red squirrel 
 living in northeastern United States, and the gray squirrel 
 
 inhabiting the for- 
 ests east of the 
 Rocky Mountains. 
 The red squirrel 
 deserves to be ex- 
 terminated, as it 
 drives away the 
 gray squirrel and 
 destroys the eggs 
 and young of the 
 song birds. The 
 marmots are bur- 
 rowing rodents 
 much larger than 
 the true squirrels. 
 The woodchuck (Marmota monax) abounds nearly every- 
 where east of the Rockies. Instead of storing up food 
 like the squirrels it hibernates during the cold season, and 
 when removed from its burrow in winter appears to be in 
 an unconscious condition. The heart beats but a few 
 times per minute and respiration is very slow, so that the 
 food stored up largely in the form of fat in its own body 
 enables it to pass the cold season without eating. The 
 prairie dog, ranging from Texas to Canada, is a social 
 animal dwelling in large colonies sometimes more than 
 fifty miles in length. 
 
 The rats and mice (Muridce) number about one hundred 
 <and seventy-five species in North America. The muskrat 
 
 FIG. 306. A moose pushing its way through the 
 underbrush. 
 
MAMMALIA 
 
 271 
 
 is aquatic in habit, dwelling in holes along the banks of 
 streams. The brown rat (Mus dccumanus) has spread 
 from its original home in western China throughout the 
 whole civilized world. About 1730 it migrated into 
 Russia, appeared in Paris in 1750, was introduced into 
 
 FIG. 307. Camel. Photographed in the Philadelphia Zoological Gardens. 
 
 America along the Atlantic coast in 1775, and by 1850 
 had spread to the Pacific coast. It destroys young poultry, 
 eggs, and grain. Like the house mouse, it multiplies 
 rapidly, producing three or four litters annually of from 
 five to ten each. 
 
 The hares and rabbits (Leporidce) are widely distributed. 
 The former have long ears and long legs, while in the latter 
 
272 
 
 VERTEBllATA 
 
 these organs are comparatively short. Rabbits intro- 
 duced into countries where their natural enemies, hawks, 
 owls, eagles, and carnivorous mammals are not sufficiently 
 abundant to keep them in check, have become great pests. 
 In Australia they devoured the grass to such an extent 
 
 FIG. 3U8. Photograph, of the elephant showing the exte 
 the trunk. 
 
 al nares at the end of 
 
 that thousands of sheep starved to death. Fifteen million 
 skins were exported from New South Wales in one year. 
 In some places the government has erected fences of wire 
 netting to keep the pests from destroying the crops. Since 
 the killing off of the coyotes and wolves in western United 
 States, the jack rabbits have increased enormously, so 
 
MAMMALIA 
 
 273 
 
 that at intervals 
 " drives" are held. 
 On these occasions 
 as many as twenty 
 thousand animals 
 are slain in one 
 day. 
 
 Bats and Flying- 
 Foxes (Chiroptera). 
 Unlike most of 
 the rodents, the 
 greater number of 
 the chiroptera are 
 beneficial on ac- 
 count of the harm- 
 ful insects they 
 
 destroy. They are nocturnal and spend the day in caves 
 and forests. The bones of the fingers are much extended 
 
 FIG. 309. Woodchuck or ground hog. Photograph 
 one fourth life size. 
 
 FIG. 310. The red bat photographed from beneath. Half life size. 
 
274 
 
 VERTEBRATA 
 
 so as to subtend the large membrane stretching from the 
 hind limb, thus affording the means of flight. Among 
 the insect eaters occurring in our land are the red bat and 
 brown bat flitting through the air at twilight. The fruit 
 eaters or flying foxes, including some species with a wing- 
 spread of three feet, inhabit southeastern Asia and adja- 
 cent islands. The vampire bats are confined to Central 
 
 FIG. 311. Short-tailed shrew 
 
 o thirds life size. 
 
 America and South America and the West India Islands. 
 While a few of them, such as the Javelin bat, suck the 
 blood from horses and cattle and even attack man, the 
 majority are insect or fruit eaters. 
 
 Insect Eaters (Insectivora). -Although members of 
 this order are common in every state, but few people have 
 seen them, because they pass their lives in underground 
 burrows seeking insects and earthworms. As their eyes 
 are of no use in the dark, they have become rudimentary 
 
MAMMALIA 
 
 275 
 
 in many species and appear as mere dark spots. The 
 shrews, numbering thirty-five species, are characterized by 
 a pointed nose and small feet, while the moles have ex- 
 tremely large fore feet enabling them to excavate rapidly 
 the tunnels whose elevated roofs form serpentine figures 
 over the lawns. The hedgehogs, distributed throughout 
 
 Fio. 312. Wild cat (Lynx rufus). Photographed in the American Museum of 
 Natural History. 
 
 Europe, Africa, Asia, and some of the adjacent islands, are 
 covered on the upper surface with an armature of spines, 
 and possess the power of rolling themselves up into the 
 form of a ball. 
 
 Flesh Eaters (Carnivora). Nearly a hundred species 
 belonging to this order dwell in North America. Their 
 distinguishing features are large canine teeth, flesh-cutting 
 
276 VERTEBRATA 
 
 molars, and clawed toes. The cats (Felidce) are repre- 
 sented in this country by the jaguar of Texas, the puma or 
 mountain lion of the western states, Adirondacks, and 
 Florida, and the bay lynx, called wildcat or catamount, 
 
 B*IG. 313. Red foxes at the entrance to their underground home. Photographed 
 in the American Museum of Natural History. 
 
 inhabiting the thickets of nearly all the states east of the 
 Mississippi. 
 
 The domestic cat is thought to be a descendant of the 
 Egyptian cat (Felis caffra) widely distributed in Africa. 
 The lion and tiger, dwelling in the Old World, are the most 
 formidable of the tribe. In India the tiger is said to 
 destroy twenty thousand cattle annually. Certain indi- 
 
MAMMALIA 
 
 277 
 
 viduals acquiring a love for human flesh are known as man- 
 eaters. To these, several hundred of the natives of India 
 fall victims every year. 
 
 The dogs (Canidce) include the wolves and foxes. The 
 coyote and prairie wolf breed hi the rocky caverns and 
 washouts of the Rocky Mountain region and the great 
 
 FlG. 314. The Weasel (Putorius erminea) in winter. One fourth natural size. 
 
 plains, and make life uncertain for the cattle, sheep, and 
 poultry. A study of structure and habits makes it evident 
 that many of the one hundred and fifty varieties of our 
 domestic dog (Canis familiaris) originated from wolves, 
 wliile it is probable that others are descendants of jackals. 
 The foxes, of which there are four species hi our country, 
 are much valued for their fur. The red fox (Vulpes ful- 
 vous), widely distributed east of the Mississippi, exhibits 
 
278 VERTEBRATA 
 
 a remarkable variation in the color of its fur. While ordi- 
 narily of a reddish hue it occasionally varies to a jet black. 
 The red skin is valued at only one or two dollars, but a 
 black one sometimes sells for as much as two thousand 
 
 FIG. 315. Polar bear (Thalarctosmaritimus). Photographed in the Philadelphia 
 Zoological Gardens. 
 
 dollars. The gray fox is confined to the more southern 
 portions of the United States. 
 
 The marten family (Muslelidce) includes the fish-loving 
 otter, slender-bodied mink and weasel, the marten, skunk, 
 and badger, all of which are valuable fur-bearing animals. 
 The weasel and mink are destructive to poultry, but the 
 weasel atones for his evil by terrorizing the rats and mice. 
 
MAMMALIA 
 
 279 
 
 Like many other creatures in the north the weasel changes 
 from brown to white in winter. The source of the white 
 ermine is the stoat or ermine occupying the northern part 
 of both hemispheres. 
 
 The bears ( Ursidce) are represented in our country by 
 four species, of which the black bear ( Ursus americanus) 
 has the widest range. It is found in many of the forests 
 
 FIG. 316. The California sea lion (Zalophus calif omianus). Photographed in the 
 Philadelphia Zoological Gardens. 
 
 from Florida to Alaska. The color varies frequently to a 
 brown in the western states, where it is called the cinnamon 
 bear. The large grizzly bear of the Rockies is said to have 
 killed and maimed more hunters than all the other bears 
 of the world combined. The polar bear inhabits the coast 
 of the Arctic Ocean, where it feeds upon fish and seals. 
 
 The Pinnipedia include those carnivora whose limbs are 
 adapted for swimming. They are the sea lions, seals, and 
 walruses. The large canines forming the long ivory tusks 
 in the upper jaw distinguish the walrus from the other two 
 
280 
 
 VERTEBKATA 
 
 groups. The sea lions resemble the seals, but have no 
 external ears and no hair or claws on the front flippers. 
 The neck of the sea lion is much longer than that of the seal. 
 Sealskin fur is not derived from a seal, but from the sea 
 lion (Callolaria ursina), breeding only in the region of the 
 Behring Sea, although making circuits in winter as far 
 south as San Francisco. 
 Primates. This order includes the lemurs, monkeys, 
 
 FIG. 317. Skull of man on the right and young chimpanzee on the left. Photograph. 
 
 and man, all of which have hands and handlike feet, and 
 in most cases the thumb is opposable to the fingers, so as 
 to grasp a limb. The lemurs of Madagascar are the lowest 
 Primates, and with the exception of their grasping hands 
 and feet resemble externally some of the Carnivora. The 
 common black and white lemur is about as large as a cat. 
 About twenty species of monkeys of a low order extending 
 from Mexico to Brazil are included in one family, the 
 marmosets. They are all small, but few being larger than 
 squirrels, and are characterized by toes with pointed claws, 
 
MAMMALIA 
 
 281 
 
 a nonopposable thumb, and the absence of wisdom teeth. 
 The Neiv World monkeys are marked by a flattened nose 
 with the nostrils separated by a broad septum. They 
 range from Mexico to Brazil. Many of them have pre- 
 hensile tails with which they are able to support themselves 
 from the limbs of trees. 
 
 The best known groups of the Old World monkeys are the 
 baboons, apes, and gibbons. The baboons have long, 
 doglike noses and 
 live only in Af- 
 rica. They travel 
 in troops of a dozen 
 or more, robbing 
 grain fields and 
 fighting fiercely 
 when attacked. 
 
 The anthropoid 
 apes (Simiidce), of 
 which there are 
 about ten species, 
 include those mon- 
 keys having no 
 tails and for the 
 mosL part bearing 
 a striking resem- 
 blance in structure 
 to man. The gib- 
 bons are of small 
 size, slender pro- 
 portions, and of low intellect. They inhabit Borneo, Su- 
 matra, the Malay Peninsula, and Siam, The gorilla (Gor- 
 
 FIG. 318. Gorilla shot and photographed in West 
 Africa. By permission of the Academy of Natural 
 Sciences. 
 
282 
 
 VERTEBRATA 
 
 ilia gorilla) is the largest, fiercest, and most manlike of the 
 apes. It is the only one which walks erect without being 
 taught, and in its home land along the equator of Africa 
 it is said to spend much time on the ground. It does not 
 thrive in captivity. Only one live specimen has ever 
 arrived in the United States. 
 
 The chimpanzee, half as large as the gorilla, has brain, 
 face, ears, and hands more manlike than those of any other 
 ape, and is the most intelligent of the group. Sally of the 
 
 FIG. 319. Photograph of a chimpanzee. 
 
 London Zoo could count up to five. Its home is in the 
 dense forests of equatorial Africa. The orang-outang, 
 about two thirds as large as the gorilla, may be distinguished 
 from the black-haired chimpanzee by its reddish hair, 
 
MAMMALIA 
 
 288 
 
 brown skin, and small ears. It manifests an intelligence 
 almost equal to the chimpanzee. The young are readily 
 trained to sit at a table, eat with a spoon, drink from a 
 cup, and give other performances. It lives in Borneo and 
 Sumatra. 
 
 Structure of a Mammal. The structure of a mammal 
 may be understood by dissecting any one of the smaller 
 forms, such as the rat, guinea pig, rabbit, or cat. Although 
 
 FIG. 320. Side view of the muscles of the cat's body. An irregular rectangular 
 piece has heen cut from each of the tAvo large side muscles and the two limbs 
 have been cut off near'the middle showing the bones white. From Davison's 
 " Mammalian Anatomy." 
 
 the description here given applies specially to the cat, 
 yet any of the other species named may be used, as the 
 structure of all is practically the same. The animal can 
 be painlessly killed in twenty minutes by placing it in a 
 small, tight box or tin can containing a cloth or piece of 
 cotton wet with an ounce of chloroform or ether. 
 
 The skin should be removed by making a slit in it along 
 the median ventral line and by pulling the cut edge outward 
 
284 
 
 VERTEBRATA 
 
 hu 
 
 and severing the white 
 fibrous connective tissue 
 uniting the skin to the 
 muscles. Many of the 
 five hundred muscles 
 forming the flesh are seen 
 to be composed of three 
 parts. The white glisten- 
 ing part usually connect- 
 ing the muscle at either 
 end with the bone is the 
 tendon, and the larger 
 middle portion is called 
 the belly. In many cases 
 the muscle fibers are at- 
 tached directly to the 
 bone without any inter- 
 vening tendon. The na- 
 ture of the thousands 
 of striated muscle fibers 
 forming the muscle is 
 easily demonstrated by 
 tearing into minute shreds 
 with two sharp needles 
 a bit of muscle placed in 
 a little water or alcohol 
 on a glass slide, and then 
 examining it under the 
 
 FIG. 321. Muscles on the outer side of the high power of the micro- 
 cat's fore limb. A piece has been cut from I 
 
 the triceps. The white cords in the region of SCOpe. A COVer glaSS 
 
 the foot are tendons; an, a ligamentous band. oVi^l^ U rlar^rl rm tVo 
 
 From Davison's" Mammalian Anatomy." SnOUlCL D6 plated On me 
 
MAMMALIA 
 
 285 
 
 specimen and care taken that there is sufficient liquid 
 to fill the space between the slide and cover glass. By 
 pulling on the muscles in the lower part of the limbs it 
 may be seen that those on the back side bend the digits 
 and are therefore called flexors, while those on the front 
 side straighten the digits and are accordingly named ex- 
 tensors. Those muscles attached to the upper limb regions 
 pulling them outward are the abductor -s, while those draw- 
 ing them inward like the great breast muscle are adductors. 
 
 Brain 
 
 Spleen* 
 Stomach \AovtaJena.Cava 
 
 Des. 
 Mon 
 
 Esophagus 1 rv ^ 
 
 Heart 
 
 Liver 
 
 \ n Jquntun, 
 Duodenum 
 
 FIG. 322. Diagram of the chief organs of a mammal. The bones are black, a, 
 opening from the nasal cavity s to pharynx ; bl, bladder ; ce, caecum ; di, dia- 
 phragm ; e, epiglottis ; n, nostril or anterior nares ; ov, ovary ; rf and ute t 
 uterus ; ru and lu, ureters ; x, pancreas ; vag, vagina. From Davison's " Mam- 
 malian Anatomy." 
 
 By cutting away the thin layer of muscle forming the 
 ventral wall of the body cavity the internal organs may 
 be examined. The diaphragm, a thin plate of muscle, 
 divides the thoracic cavity containing the heart, trachea, 
 lungs, and esophagus from the abdominal cavity contain- 
 ing the stomach, intestines, the large dark red liver com- 
 posed of several lobes adjacent to the diaphragm, the 
 pinkish-white pancreas lying along the bend of the intes- 
 
286 
 
 VERTEBKATA 
 
 tine near the stomach, the dark-red tongue-shaped spleen, 
 a kidney on either side of the backbone, and a pear-shaped 
 urinary bladder into which two ureters lead from the 
 
 kidneys. The thin 
 transparent mem- 
 brane lining the 
 abdominal cavity 
 and investing the 
 organs therein is 
 the peritoneum. 
 The similar mem- 
 brane in the thorax 
 is the pleura. These 
 membranes secrete 
 a colorless serum 
 and are therefore 
 called serous mem- 
 branes, to distin- 
 guish them from 
 the mucous mem- 
 branes lining the 
 alimentary canal 
 and all other cavi- 
 ties to which the 
 air has access. 
 
 By cutting a 
 small slit in the 
 windpipe distinguished by its numerous incomplete car- 
 tilaginous rings, and inserting and tying fast therein the 
 end of a small glass or thin tube through which to blow, 
 the lungs may be inflated as in inspiration performed by 
 
 Fig. 323. Photograph of a lung corrosion prepared 
 by Mr. Sylvester. The trachea with all of its 
 branches was filled with melted white wax and 
 the pulmonary artery was filled with red wax, and 
 the specimen then placed in a jar of acid to eat 
 away the lung tissue, t, trachea ; a, artery to right 
 lung ; 6, left bronchus giving off air tubes to the 
 left lung. The expanded air sacs at the ends of the 
 minute branchlets are broken off. FromDavison's 
 
 i " Mammalian Anatomy." 
 
MAMMALIA 
 
 287 
 
 the living animal. The two vocal cords may be seen by 
 cutting the larynx lengthwise. They are flat ligamentous 
 folds on either side 
 of the larynx. 
 
 The vessels re- 
 maining full of 
 blood are the veins. 
 The arteries are of 
 a lighter color, and 
 contain little or no 
 blood. The main 
 vein of the trunk 
 is the vena cava, 
 which opens into 
 the upper right 
 cavity of the heart, 
 called the right 
 auricle. From here 
 the blood passes 
 to the right lower 
 cavity, termed the 
 right ventricle, 
 which by the con- 
 traction of its 
 strong muscular 
 walls forces the 
 blood through the 
 pulmonary artery 
 to the lungs, to exchange the carbon dioxide, a waste 
 substance collected from all parts of the body, for 
 oxygen. The blood is returned from the lungs bysev- 
 
 FIG. 324. Cat's brain viewed from above, a, &, c, 
 convolutions of the cerebrum ; ce, and v, cerebel- 
 lum ; md, medulla oblongata ; n, stump of the 
 nerve supplying the shoulder region ; sp, spinal 
 cord ; ad, body of nerve cells forming the gray 
 matter ; ac, processes of nerve cells forming white 
 matter. Three fourths natural size. From Davi- 
 son's " Mammalian Anatomy." 
 
cb 
 
 n, 
 
 cc 
 
 FIG. 325. Cat's brain viewed from beneath. The numbers refer to the nerves 
 supplying the head and neck ; i, io, ir, ex, and x, muscles for moving the eye- 
 ball ; , optic nerve ; op, optic chiasm ; ol, olfactory lobe ; sy, cerebrum ; cb, 
 cerebellum ; an, medulla oblongata ; pv, pons Varolii ; cc, spinal cord. 
 Slightly enlarged, From Davison's "Mammalian Anatomy." (288) 
 
MAMMALIA 
 
 289 
 
 eral veins emptying into the left upper cavity known as 
 the left auricle and then goes to the left ventricle, which 
 by contraction of its walls propels the blood through 
 the aorta and its 
 branches to all 
 parts of the body. 
 The membranous 
 valves, held by 
 white glistening 
 cords, between the 
 auricles and ven- 
 tricles prevent the 
 backward flow of 
 the blood. 
 
 The nerves are 
 the white glisten- 
 ing cords extend- 
 ing along with the 
 blood vessels and 
 giving off numer- 
 ous branches to the 
 muscles and other 
 structures. They 
 are connected 
 either with the 
 spinal cord or the 
 brain. Those 
 nerves which cariy sense stimuli, such as sound or a pin 
 prick to the brain or spinal cord, are called sensory nerves, 
 while the others bearing impressions from the brain or 
 spinal cord to the muscles are termed motor nerves. The 
 
 FIG. 326. Nerve cell from the brain ; a, processes 
 by which it communicates with other cells near by ; 
 ax, long process or axis cylinder terminating in the 
 tail end of the spinal cord ; n, nucleus. Enlarged 
 two Lundred diameters. From Davison's " Mamma- 
 lian Anatomy." 
 
290 VERTEBRATA 
 
 spinal cord and brain form the central nervous system 
 which the microscope shows to be composed of millions 
 of cells with processes varying in length from a hundredth 
 of an inch to nearty a foot. The longer processes are 
 called fibers, and many of them bound together form a 
 nerve such as is most distinctly seen in the limbs. 
 
 The brain of mammals is composed of five parts: the 
 medulla oblongata, the cerebellum, the cerebrum visible 
 from above, and the rn'id brain and interbrain lying beneath 
 the cerebrum. The intelligence of an animal seems to 
 depend largely on the size and structure of the cerebrum. 
 In the lower mammals the surface is quite smooth, while 
 in the rabbit and cat it is somewhat convoluted, and in ape 
 and man the convolutions become very numerous. The 
 average weight of the male human brain is about three 
 pounds; of a female about two and two thirds pounds. 
 The human brain is one forty-fourth the weight of the body ; 
 the ape's one twenty-ninth; the rat's one eighty-second; 
 the sheep's one three hundred and fifty-first, and the ele- 
 phant's one five-hundredth. The brain of man is larger 
 than that of any other animal except the whale and ele- 
 phant. The brain of a large whale weighs over four pounds, 
 while that of a large elephant will weigh about ten pounds. 
 
 The skeleton of the cat consists of more than two hundred 
 bones united to each other by tough bands of tissue called 
 ligaments. The three parts of the skeleton are the head, 
 trunk, and extremities. Except the lower jaw, the bones 
 of the head are immovably united to each other. The 
 bones of the trunk are capable of only limited motion, but 
 free movement occurs between several of the limb bones. 
 A typical mammalian fore limb consists of a shoulder blade 
 
MAMMALIA 
 
 291 
 
292 VERTEBRATA 
 
 or scapula, the arm bone or humerus, the ulna and radius 
 in the forearm, several small bones in two rows forming 
 the carpus or wrist, and five metacarpal bones in the hand, 
 each bearing three phalanges, except the first, which has 
 only two. In the hind limb the femur occupies the thigh 
 region, while the tibia and fibula in the lower part of the 
 leg join the several small bones of the ankle to which are 
 united the five bones of the foot, called metatarsals, each 
 bearing three phalanges, except the first, which has only two. 
 In many forms some of the digits are wanting and others 
 are more or less rudimentary, as in the cattle, horses, and 
 pigs. In some cases the ulna and radius are grown to- 
 gether, as are also the tibia and fibula, and in these species 
 the ulna and fibula are usually rudimentary. 
 
PART IV 
 ANIMAL LIFE 
 
 20. FROM EGG TO ADULT 
 
 Eggs of Animals. With the exception of the Protozoa, 
 all species produce specialized cells capable under certain 
 conditions of developing into new animals similar to the 
 parents. Such cells are known as ova or eggs. These are 
 so small in some of the invertebrates as to be invisible to 
 the naked eye, while in some of the fish the}' are as large 
 as a pinhead, and in reptiles and birds many times larger- 
 The egg of the alligator is more than two inches in diameter, 
 
 FIG. 328. Eggs of vert 
 woodpecker 
 
 tebrates, a, pond turtle ; b, black snake ; c, garter snake ; rf, 
 ; e, lizard. Photograph two thirds natural size. 
 
 and that of the ostrich is more than six inches. The real 
 difference between the small egg of the fish and the large 
 egg of the bird is in the amount of the yolk and albumen 
 
294 ANIMAL LIFE 
 
 stored up as food for the young. Within the shell of a hen's 
 egg is sufficient food to nourish the growing chick, called 
 the embryo, until it is able to run about. If a fresh egg be 
 placed in water and a circular piece of shell removed with 
 the scissors, a white spot a quarter of an inch in diameter 
 lying on the yolk is seen. This is a young chick composed 
 
 PIG. 329. At the left a fresh hen's egg showing the young chick at the center. 
 At the right an English sparrow one day old. Photograph. 
 
 of several hundred cells which have developed during 
 twenty-four hours from the one cell formerly occupying 
 this place. Some birds are in a helpless condition when 
 hatched, and must be fed by the parents several days before 
 they can fly or walk. The eggs of frogs and toads contain- 
 ing but little food material for the young are small, and in 
 growing the whole egg may be seen with the naked eye 
 to divide into two cells within two or three hours after 
 
FROM EGG TO ADULT 
 
 295 
 
 FIG. 330. Strings of toads' eggs each of which is a single cell. Photograph nat- 
 ural size. 
 
 being deposited in the water. An hour later four cells 
 are visible, then eight cells, after which division occurs 
 more rapidly (Fig. 332). 
 
 Many animals retain their eggs in the body during 
 development. Such are certain flesh flies, plant lice, 
 some of the sharks, the copperhead, rattlesnake, and most 
 mammals. 
 
 Development of Young. In numerous species, the 
 young does not continue its development uninterruptedly 
 but at certain periods rests and undergoes remarkable 
 
296 
 
 ANIMAL LIFE 
 
 FIG. 331. Amphibian egg of two 
 cells with the furrow forming to 
 divide it into four cells. Photo- 
 graph through the microscope 
 enlarging twenty diameters. 
 
 changes in form and structure. 
 The egg of the jellyfish does 
 not produce directly the free- 
 swimming parent form, but 
 develops into what is known as 
 the hydra tube (Fig. 203), which 
 after a time by transverse di- 
 vision gives rise to several 
 jellyfish. The egg of a tape- 
 worm eaten by an animal 
 becomes in a favorable host 
 a somewhat globular body 
 known as the cysticercus or 
 larva. In this condition it may live for months or 
 possibly years until the flesh containing it is eaten 
 by the proper host 
 for the develop- 
 ment into the com- 
 plete tape form. The 
 larva of the cat's 
 tapeworm lives in the 
 mouse, and the tape- 
 worm of the dog is a 
 cysticercus in the rab- 
 bit (Figs. 184, 185). 
 
 Among the insects 
 very marked differ- 
 ences in form occur 
 during the life of 
 
 FIG. 332. Frog's eggs from three to ten hours 
 
 the yOUng. In SOme old. All stages from four cells to thirty-two 
 
 i , ,-, cells may be noted. Photograph enlarged 
 
 orders, such as the four times. 
 
FROM EGG TO ADULT 
 
 297 
 
 Neuroptera, Coleoptera, Diptera, Lepidoptera, and Hymen- 
 optera, as many as four stages are distinguished in the life 
 
 FIG. 333. One fourth of the eggs laid by a silk-worm moth. Twice natural size. 
 
 cycle. The transformation from one stage to the next is 
 called metamorphosis. 
 
 The egg hatches into the larva, which is a wingless and 
 often wormlike form havino; but little resemblance to the 
 
 FIG. 334. Promethea moth, larva and adult. Photograph nearly natural size 
 
298 ANIMAL LIFE 
 
 parent. The larval stage may continue from 
 three days to three years, depending largely 
 on the species but somewhat upon the food 
 and temperature. It is longest in the Coleop- 
 tera and Neuroptera. Before entering the 
 third stage, that of pupa t the larva some- 
 times forms a case of particles of earth, or 
 weaves a cocoon from its silk glands or from 
 hairs of its body (Fig. 75). The deathlike 
 sleep of the pupa continues from a week to a 
 year, depending upon the species. No food 
 is taken and any temperature from twenty 
 degrees below zero to one hundred degrees 
 above does not seem to harm the insect, but 
 the wonderful reorganization of structure 
 necessary to assume the form of the parent 
 does not take place except during mild 
 weather. The adult stage is usually a winged 
 form, which may not live more than a week, 
 as in the case of many moths, or may exist 
 five or six years, as in the case of the queen 
 honey bee. 
 
 Some insects, such as the locusts, grass- 
 hoppers, cicadas, dragon flies, and May flies, 
 do not exhibit any marked difference in form 
 between the larval and pupal states, and are 
 therefore spoken of as having an incomplete 
 metamorphosis (Figs. 7, 140). The young is 
 then usually called ihenymph 
 
 FlG. 335. Metamorphosis of the cicada . . . .. 
 
 as it occurred between 8 P.M. and and Continues active at all 
 
 times. Often the life of the 
 
FROM EGG TO ADULT 299 
 
 adult insect is passed in a realm quite different from that 
 of the larva. The mature dragon flies, May flies, and 
 hellgramite are inhabitants of the air, while the larval 
 young dwell in the water. The adult cicadas love the 
 pure air and sunshine, but their larvae are subterranean 
 wanderers. 
 
 Many of the crustaceans exhibit a complete metamor- 
 phosis, and in numerous species three or four stages are 
 discernible. In the case of the small crustaceans (Ento- 
 mostraca), including the barnacles and shrimps, the larval 
 form hatching from the egg is known as the nauplius. It 
 differs from the adult in having usually but one eye and 
 three pairs of leglike appendages which later become trans- 
 formed into the antennules, antennae, and mandibles. 
 The body is not segmented. In the barnacles a second 
 larval stage occurs, called the cypris, characterized by a 
 two-valved shell, six pairs of swimming feet, and paired 
 compound eyes. Certain of the larger crustaceans (Mala- 
 costraca) exhibit two stages in development known as 
 zoea and my sis. The larval stages last but a few days, 
 and in any species are passed through in the egg. 
 
 Some of the mollusks, especially the bivalves, pass 
 through a larval state known as the veliger. It is a minute, 
 free-swimming form. In the case of the fresh-water mussel 
 a second larval stage occurs, while as a parasite it is at- 
 tached to a fish. The eggs of the sea-urchin and starfish 
 do not hatch directly into forms resembling the parents, 
 but give rise to young differing as widely from the adult 
 as the caterpillar differs from the butterfly. 
 
 Even among vertebrates, as in the case of some fish and 
 all amphibians, the development from egg to adult is 
 
300 
 
 ANIMAL LIFE 
 
 indirect. The larva of the lamprey eel presents features 
 of such contrast to its parent that for many years it was 
 
 FIG. 336. Metamorphosis of a shrimp, a, nauplius ; b, first zosea stage ; c, sec- 
 ond zosea stage ; d t mysis stage ; e, adult. From Weismann after MUller. 
 
 considered an animal of different species and named Ammo- 
 coetes. It has an over-arching upper lip instead of a 
 round sucking mouth, rudimentary eyes, and gill pouches 
 opening into the pharynx instead of into a respiratory 
 
FROM EGG TO ADULT 
 
 301 
 
 tube. It spends four or five years in the mud along the 
 banks of the stream, while the adult is a free swimmer 
 
 2 
 
 FIG. 337. Life cycle of the frog passed through in four months. 1, mass of eggs; 
 2, month-old legless tadpole. Photograph one half life size. 
 
 (Fig. 215) in the ocean. The young of the bony eel is 
 likewise very different in form from its parent. 
 
 Very remarkable 
 transformations occur 
 among the amphibians. 
 Most of them hi the 
 adult state are air 
 breathers, but with few 
 exceptions the larvse 
 
 Fio 33S. Axolotl or larval form of an am bly- 
 /toma. Photograph from life. 
 
ANIMAL LIFE 
 
 are aquatic. The common toad, though a lover of the 
 dryest soil, habitually repairs to the quiet pool in late 
 spring to deposit its five thousand eggs in a gelatinous 
 
 FlG. 339. Mature Ainblystoma one half natural size. 
 
 string, from whence issue in a week the well-known black 
 tadpoles, legless and lungless, and in fact with no sem- 
 blance to their warty 
 mother. They breathe by 
 means of gills, to which 
 there is a small opening 
 on the left-hand side of the 
 neck. In a month or two 
 hind legs appear and the 
 front ones break through 
 the skin as the tail begins 
 to be absorbed. Mean- 
 while, lungs have developed 
 witliin and the young, an 
 inch or less in length, are 
 
 ready for life On land. FIG. 340. Embryo snake within the egg 
 <_ f ,-, , . from which the top of the shell has 
 
 Progs frequently continue been cut away. 
 
SENSES OF ANIMALS 303 
 
 in the larval stage over winter, hiding in the mud at the 
 bottom of the ponds. One of the urodeles, the axolotl, 
 usually continues in its larval condition throughout life. 
 The drying up of the water causes it to assume the adult 
 form when it is known as an amblystoma. Cold and lack 
 of food may prolong the larval life of some species several 
 months. 
 
 Among the higher vertebrates the developing young, up 
 to the time when it assumes the characteristic form of 
 the parent, is called the embryo. 
 
 21. SENSES OF ANIMALS. 
 
 Sense of Feeling. There are probably no animals, 
 however simple in structure, which do not respond to cer- 
 tain kinds of stimuli. While it is true that none of the 
 protozoa or sponges and but few of the worms and mol- 
 lusks can see or hear, yet the sense of feeling seems to be 
 present in all animal life. The amoeba can distinguish 
 between a particle of sand and a bit of flesh. The Para- 
 mceeium brought from darkness into bright light responds 
 by vigorous movements, owing doubtless to the fact that 
 the protoplasm of all parts of the body is sensitive to the 
 light rays, but the animal can not be said to see. The 
 more complex the nervous system the more acute is the 
 sense of feeling, which is the only sense with organs 
 widely distributed over the body. The most sensitive 
 parts in the Hydra and sea anemone (Fig. 342) are the 
 tentacles. The loss of a leg or wing or even of a portion 
 of the body of an insect seems to cause the creature little 
 or no pain. With a pair of sharp scissors one may 
 cut a third of the abdomen off the mosquito while it is 
 
304 
 
 ANIMAL LIFE 
 
 sucking blood, and the parasite will in some cases continue 
 feeding. 
 
 Among the higher vertebrates some areas of the skin are 
 more sensitive than others. If the points of two phis be 
 pressed to the skin at a distance of less than two inches 
 
 PIG. 341. The slipper animalcules (Paramceciuni). Photograph from life through 
 the microscope. 
 
 apart on the middle of the human back, only one point 
 will be felt, but on the tip of the tongue two separate 
 points may be distinguished when only one twenty-fifth 
 of an inch apart. In the higher animals the sense of feel- 
 ing depends upon the presence of special nerve termina- 
 tions from which lead nerve fibers to the spinal cord or 
 
SENSES OF ANIMALS 305 
 
 brain. In the mesentery of the cat the oval nerve ter- 
 minations are just large enough to be clearly visible to the 
 naked eye (Fig. 343). 
 
 The sense of taste is located in the mouth or near the 
 entrance to it. Among mammals it depends upon certain 
 
 FIG. 342. Sea anemone, m, mouth ; the projecting mass at the right is a bud 
 which will soon form a new animal. Photograph two thirds natural size. 
 
 nerve terminations in the mucous membrane of the tongue, 
 palate, and neighboring regions. Special flask-shaped 
 endings are numerous in the several large papilla arranged 
 in a V-shape at the back of the tongue. So acute is the 
 sense of taste in the human that a woman is said to have 
 detected one part of quinine in five million parts of water. 
 Little is known concerning the sense of taste in the 
 
306 
 
 ANIMAL LIFE 
 
 FIG. 343. Sensory nerve ter- 
 mination in the mesentery of 
 the cat. From Davison's 
 " Mammalian Anatomy." 
 
 lower vertebrates, but numerous 
 experiments have been made with 
 insects. Most caterpillars will re- 
 fuse all but one or two kinds of 
 leaves, and many bugs will die of 
 starvation rather than suck the 
 juice of plants to which they are 
 not accustomed. When the sugar 
 upon which bees are feeding is ex- 
 changed for pulverized alum, the 
 insects splutter and spit in a way 
 that indicates a well-developed 
 sense of taste. Ants love sugar, 
 but if strychnine is mixed with it 
 
 they reject the food at once. The organs of taste in 
 
 insects are minute pits containing fine 
 
 taste hairs. They are present in the 
 
 maxilla and tongue of ants, bees, and 
 
 wasps, and on the proboscis of the 
 
 flies. 
 The sense of smell varies widely in 
 
 efficiency among the different animals. 
 
 It is well developed in most terrestrial 
 
 mammals, but more or less rudimen- 
 tary in the other classes of vertebrates. 
 
 A dog familiar with the smell of 
 
 his master can track him through a 
 
 crowded street with the same ease 
 
 that we can follow a man by sight. A 
 
 deer will discern the presence of man 
 
 a half mile distant to windward. It 
 
 FIG. 344. Head of the 
 bumblebee, a, anten- 
 na ; g, glossa or tongue 
 used in licking the nec- 
 tar from flowers ; l t 
 paraglossa; m, maxil- 
 lae. Photograph. 
 
SENSES OF ANIMALS 307 
 
 is probaHe that a few birds and also fish use the sense 
 of smell in seeking food. The special end organs of this 
 sense in the vertebrates is located in the mucous membrane 
 lining the upper parts of the nasal cavity, whence a pair 
 of nerves convey the stimuli to the brain. 
 
 With the exception of arthropods, but little is known 
 concerning the sense of smell among the invertebrates. 
 Many insects have a keen sense of smell. A piece of decay- 
 ing meat so covered that it can not be seen will, on a warm 
 day, attract numerous flies, some of which apparently scent 
 it at a, distance where no odor is discernible to man. Many 
 of the social insects recognize the members of their house- 
 hold by smell, and the male of some species seeks his mate 
 by the olfactory sense. Among insects the organs of smell 
 are located in the antennae or palps. Male bumblebees 
 with the antennae removed can not find their mates (Fig. 
 344). Some crustaceans seem to possess organs of smell 
 on the antennules. 
 
 The sense of hearing is most acute in mammals and birds. 
 The organ of hearing, which is a portion of the internal 
 ear located on either side of the head, responds to certain 
 vibrations productive of sound waves in the atmosphere. 
 It is probable that all normal vertebrates with the excep- 
 tion of some fish and certain tailed amphibians are capable 
 of hearing. In the frog, the large round tympanic mem- 
 brane back of the eye (Fig. 239) is similar to the tympanic 
 membrane of birds and mammals located at the inner end 
 of a short canal on either side of the head. It transmits 
 the vibrations affecting it to the inner ear, which is an 
 irregular sac filled with liquid, and containing the termina- 
 tions of the nerve of hearing. No tympanic membrane 
 
808 ANIMAL LIFE 
 
 is present in fish, salamanders, or snakes, which fact ac- 
 counts in part for their partial deafness. 
 
 More simple auditory organs are found among some of 
 the invertebrates. These consist of small sacs containing 
 a clear liquid with one or more tiny lime nodules, called 
 otoliths. Specialized cells often bearing vibratile hairs 
 line more or less of the inner surface of the sac. Organs 
 of hearing or equilibration are present in the margin of the 
 umbrella of certain jellyfish, in the head of a few worms, 
 in the foot of the mussel, in the head of the snail, in the 
 first segment of the antennules of the crayfish, and in some 
 other crustaceans in the tail. Hearing among insects is in 
 many species quite acute, and it is probable that they are 
 aware of some sounds that make no impression on our 
 ears. In a few insects a vibrating tympanic membrane 
 occurs as may be seen in the common locust, having the 
 ear on the side of the first abdominal segment. The true 
 grasshoppers and crickets have an ear on the front leg. The 
 oval tympanic membrane may be seen with the naked eye 
 on the outer surface of the tibia of the common large 
 cricket. It has the same location in ants. Certain other 
 insects possess a complex organ of hearing at the base of 
 each antenna. 
 
 Sight is undoubtedly the most important sense of all for 
 animals living in the light, because it not only aids them 
 greatly in securing food, but also in escaping from their 
 enemies. All vertebrates have eyes or rudiments of them. 
 Moles living underground, insects, crustaceans, fish, and 
 amphibians inhabiting caves, and some fish living at great 
 depth in the sea have eyes of such a rudimentary char- 
 acter as to be of no use. The larger mammals can sight 
 
SENSES OF ANIMALS 
 
 309 
 
 objects at a distance of many miles, but the keenest vision 
 is probably possessed by birds. A fish hawk at a distance 
 of two hundred feet will spy a fish in the stream when 
 human vision can not detect it fifty feet away. The 
 chimney swift, 
 wheeling through 
 the summer air, no 
 doubt, sees the 
 minute insects con- 
 stituting its food. 
 Most of the lower 
 vertebrates are 
 decidedly short- 
 sighted. A toad 
 does not recognize 
 a fly at a distance 
 of more than two 
 or three feet, and 
 few common fish 
 distinguish food 
 beyond five feet. 
 
 The structure of the vertebrate eye is admirably adapted 
 for its function. The eyeball is composed of the tough, 
 thick sclerotic coat, the thin black choroid coat, and the 
 pinkish retina almost surrounding the vitreous humor which 
 is separated from the aqueous humor by the crystalline 
 lens adjustable for far and near vision. The parts of an 
 eye of a cat, cow, or fish may be easily seen by cutting it 
 in two with a sharp knife. The structure is especially well 
 shown in an eye frozen before being cut. 
 
 Many of the cdeleriterates, echinoderms, worms, and 
 
 rt 
 
 FIG. 345. Section of the cat's eye enlarged twice. 
 aq, aqueous humor ; c, cornea ; ci, ciliary pro- 
 cesses ; cp, capsule surrounding the crystalline 
 lens ; ch, choroid coat ; i, iris ; lg, ligament of the 
 lens ; m, muscle to adjust the lens for far and near 
 sight ; opn, optic nerve leading to the brain ; rt, 
 retina ; sc, sclerotic coat. From Davison's 
 " Mammalian Anatomy." 
 
310 ANIMAL LIFE 
 
 mollusks have no eyes, but they are usually sensitive to light. 
 The simplest eyes are found in the jellyfish, and organs of 
 sight somewhat resembling those of the vertebrates are 
 present in the scallop (Pecten) and cephalopods (squid, cut- 
 tlefish, etc.). The snail has well-developed eyes on stalks. 
 The insects and crustaceans have acute vision, but at 
 a distance of only a few feet. Both compound and simple 
 eyes are present in most insects. If the compound eye of 
 a house fly be placed under the low 
 power of the microscope the surface 
 will appear marked off in hexagonal 
 areas. These are the ends of cones, 
 each of which may function as a sepa- 
 rate eye. The queen bee has five thou- 
 sand of them, the drone twelve thou- 
 sand > the dra S n fl y twent y thousand, 
 
 tenna ; e, compound an d SO me beetles twenty-five thousand. 
 
 eye; the three black . 
 
 dots are the simple Ihe simple eyes, called ocelli, located 
 near the middle of the forehead, are 
 just visible to the naked eye in such large forms as the 
 locust in which there are three. These are probably used 
 for very near vision. Spiders have no compound eyes, 
 but from six to eight ocelli larger than those of insects. 
 
 22. PROTECTION FROM ENEMIES 
 
 Every living animal from the amoeba to man has enemies 
 seeking its destruction, and it is only by special adapta- 
 tions that the species persists. The huge elephantlike 
 Titanotheres and Uintatheres which a few millions of 
 years ago roamed about in Western United States, became 
 
PROTECTION FROM ENEMIES 811 
 
 extinct because they had no means of protecting them- 
 selves from the furious saber-toothed tigers and other blood- 
 thirsty carnivores of those days. The buffalo of the west- 
 ern plains, the fur seal of Alaska, and the trout of the 
 mountain stream are being overcome in the struggle for 
 
 FIG. 347. Larva of caddis fly. Natural size. 
 
 existence, because they have no means of adequately pro- 
 tecting themselves from their arch enemy, man. 
 
 Many animals are provided with an external armor 
 preventing the attack of would-be foes. The sea urchins 
 are covered with spines, many of the mollusks are inclosed 
 
 FIG. 348. Photograph of io, a poisonous caterpillar. 
 
 in calcareous shells, some of the marine worms live in hard- 
 walled tubes, and the larvae of some insects such as the 
 caddis flies dwell in protecting tubes, while many cater- 
 pillars are covered with stiff or poisonous hairs. The hard 
 shell of the crustaceans and the adopted home of the hermit 
 
312 
 
 ANIMAL LIFE 
 
 crab are effective means in reducing the mortality among 
 these forms. The hard shell of the chelonians, the thick 
 skins of the alligator, tapir, and hippopotamus, the series 
 of bony plates covering the armadillo, and the spines of 
 the hedgehog, form armors of great value in the midst 
 of hostile associates. 
 
 Special weapons of defense have been developed among 
 some groups, as in the case of the wasps and bees which 
 prevent the robbing of their homes and the killing of the 
 young, by the use of poisonous stings. Men have been 
 known to die as the result of an attack by a colony of bees. 
 The tarantula and tropical centipeds protect themselves 
 
 FIG. 349. The rattlesnake defending itself against an enemy, f, poison fang; h, 
 hood holding the tooth against the roof of the mouth when not in action. 
 Photograph of posed dead snake. One third life size. 
 
 by attacking the enemy with their poisoned mandibles, 
 while the scorpion releases itself from its tormentor by 
 applying its poisonous fang at the end of the tail. The 
 torpedo, a flat-bodied fish of the Atlantic coast, and the 
 six-foot electric eel of the South American waters give a 
 
PROTECTION FROM ENEMIES 318 
 
 severe electric shock to any foe daring to touch them. 
 Some of the catfish possess poisoned barbs in the thoracic 
 fin which are used in contests. A few of the snakes have 
 a pair of long teeth, called fangs, in the upper jaw, through 
 which they inject into any creature disturbing them a 
 deadly poison. The rattlesnakes, copperhead, and south- 
 ern moccasin are the only poisonous snakes to be feared 
 in our country. 
 
 Among mammals the weapons of defense are varied. 
 The antlers of the deer and the horns of the cattle are often 
 used with telling effect against their foes. The tusks of 
 
 FIG. 350. Kallima butterfly on the right, leaf on left. Photograph life size- 
 
314 
 
 ANIMAL LIFE 
 
 the elephant render him a formidable opponent. The 
 long sharp incisors of the rodents and the pointed teeth of 
 the bats afford them sufficient aid in contests with larger 
 animals. The large canines of the carnivora and the strong 
 
 sharp claws of the 
 lion and tiger are 
 weapons of great 
 power. Some of the 
 carnivores, espe- 
 cially the skunks, 
 protect themselves 
 by the ejection of a 
 nauseous- smelling 
 fluid detested by 
 dogs, foxes, and 
 wolves. 
 
 Many animals 
 without a protective 
 armor or special 
 weapons of defense 
 seek safety in flight. 
 Such are the hares, 
 kangaroos, and some 
 birds. Others es- 
 cape by assuming 
 such attitudes and 
 colors as to make it 
 difficult for their enemies to distinguish them from the sur- 
 rounding objects. The leaf butterfly (Kallima) of India 
 when at rest on certain bushes is so similar to the leaves 
 that even the birds fail to distinguish the difference. The 
 
 FIG. 351. The walking stick (Diapheromerafem- 
 orato). Natural size. 
 
PROTECTION FROM ENEMIES 
 
 315 
 
 katydids, so numerous in late summer, have a green color 
 and venation of the wings, making them so inconspicuous 
 among the green leaves that the birds seldom detect them 
 unless they move. The walking stick insects resemble so 
 closely the twigs of the trees among which they live that 
 only the acutest vision spies the creatures so long as they re- 
 main motionless. I have known as many as twenty locusts 
 to sit in the grass within the range of distinct human vision 
 and yet be invisible until they were disturbed. Such 
 protective resemblance prevents the birds and other ene- 
 mies from exterminating the species. 
 
 The measuring worms, larva? of geometrid moths, imi- 
 tate so closely the 
 short rough twigs 
 that I have had to 
 touch the suspi- 
 cious object with 
 my hand before I 
 could be quite sure 
 that it was really 
 an animal. Many 
 of the green larvae 
 feeding on green 
 foliage escape the 
 eyes of their pur- 
 suers because of 
 their protective 
 colors. Some of 
 the crabs take on the somber color of the rocks and 
 stones among which they dwell, and sometimes bear on 
 their shells growths of seaweed and hydroids. Spiders 
 
 FlG. 352. The projection on the right is a geometrid 
 larva. Photograph life size. 
 
ANIMAL LIFE 
 
 FIG. 353. Spider crab often found covered with seaweeds and hydroids so as to 
 appear like a stone or stick. Photograph by Overton. One third natural size. 
 
 FlG. 354. Tree frog. A, after assuming a protective color ; B, before assuming 
 the dark protective color of the bark which it took on fifteen minutes later. 
 
 Photograph nearly half life size. 
 
PROTECTION FROM ENEMIES 317 
 
 in Java resemble so closely bird droppings that a trained 
 eye can not detect the difference unless at close range. 
 
 The markings of many fish are such as to harmonize 
 so completely with the variously colored bed of the stream 
 that the casual observer will not see them when only a few 
 feet distant in clear water. The tree frog is a notable 
 example of the ability of an animal to adapt its color to its 
 environment. It is able to change its color from a very 
 dark hue to a very light one in about twenty minutes, and 
 so perfectly does it agree in color with the surface of a stone, 
 a lichen, or the bark of a tree that often one is not aware 
 of its presence until he has accidentally placed his hand 
 on it. The common frogs are likewise protected by the 
 ability to change the color of the skin. Certain lizards 
 and snakes render themselves very inconspicuous by 
 taking advantage of protective coloration. 
 
 A woodcock on her nest has been known to have so 
 much faith in the protection afforded her by the brown- 
 
 G. 355. Adult woodcock and twoyotmg rendered inconspicuous by their envi- 
 ronment. Photographed in American Museum. 
 
318 
 
 ANIMAL LIFE 
 
 FIG. 356. The whip-poor-will showing protective coloration. Photographed in the 
 Academy of Natural Sciences, Philadelphia. One third life size. 
 
 FIG. 357. Protective resemblance in the bobwhite. Photographed in the Acad- 
 emy of Natural Sciences. 
 
PROTECTION FROM ENEMIES 
 
 319 
 
 leaf plumage of April that she would permit a person to 
 approach within a foot or two of her nest. A light snow- 
 fall occurring a few days later made the same bird con- 
 
 FIG. 358. The ptarmigan in summer. Photograph of mounted specimen. One 
 third life size. 
 
 spicuous, and she would fly from her nest before the ob- 
 server was nearer than fifty feet. The whip-poor-will as it 
 sits among the dead leaves in the depth of the forest appears 
 not unlike a mass of leaves some of which are browner 
 than others. The hunter, standing within ten feet of a 
 
320 ANIMAL LIFE 
 
 large flock of quail, can not see a bird until it flies, because 
 the dull-colored plumage so effectually resembles the 
 autumn leaves and tangled grass. The little screech owl 
 with his gray and brown feathers becomes inconspicuous 
 against the somber-hued barks of the forest. The ptar- 
 migan adjusts its plumage in accordance with the season, 
 
 FIG. 359 The ptarmigan in winter. Photograph of mounted specimen. 
 
 being brown in summer and white in winter. The arctic 
 fox and hare exhibit the same seasonal change. Most 
 animals of the arctic regions are white, as that is the most 
 protective color for the land of snow. The weasel in the 
 northern part of the United States and Canada is brown 
 in color during the warm months, but becomes after snow- 
 fall in early winter a pure white, except the tip of its tail. 
 
 Some animals are protected by their likeness to the form 
 of others which for various reasons are left unharmed. 
 
PROTECTION FROM ENEMIES 321 
 
 This phase of protective coloration is known as mimicry. 
 Certain flies resemble the stinging bees so closely that one 
 must catch them before he can be quite sure of their 
 identity. Some butterflies have wings like those of a 
 few species which are left untouched by the birds because 
 
 PIG. 360. The snowy owl visiting the United States only in winter. Photo- 
 graph of specimen mounted by Neal. One sixth life size. 
 
 of their bad flavor. The spotted adder (Fig. 248), a com- 
 mon harmless snake, when disturbed by an enemy coils 
 and vibrates the end of its tail much after the fashion 
 of the rattlesnake. 
 
 Were it not for protective coloration and mimicry among 
 animals certain species would doubtless have suffered ex- 
 
322 
 
 ANIMAL LIFE 
 
 FIG. 361. The weasel in summer with its prey, the mouse. Photographed in the 
 American Museum of Natural History. One sixth natural size. 
 
 tinction. It must be understood that these character- 
 istics are secured to the species, not by its own will power, 
 but through a, process of variation and natural selection. 
 
 FIG. 362. The weasel in winter. Photographed in the American Museum of 
 Natural History. 
 
PARASITISM 323 
 
 During many years in the past those which did not possess 
 protective features were killed by the ever-pursuing ene- 
 mies, while the survivors transmitted to their offspring 
 their special protective characteristics. 
 
 23. PARASITISM 
 
 Symbiosis. There are certain species of animals which 
 are always found in association with certain other species, 
 because in the struggle for existence they are mutually 
 helpful. The ants are often to be seen in company with 
 the plant lice which feed on the sap in the tender twigs and 
 leaves. From the alimentary canal of the plant lice exudes 
 a sweet fluid much sought after by the ants. The ants 
 assist the lice by transporting them to the tenderest parts 
 of the plant, and in some cases during inclement weather 
 even remove them to places of shelter. This condition 
 of intimate association for mutual benefit is known as 
 symbiosis. Some of the crabs bear on their back sponges 
 which render them less easily visible to their enemies, and 
 the crab repays the kindness by carrying the sponges to 
 good feeding-grounds. 
 
 True Parasites. A still closer association between 
 species, where only one derives any benefit, represents a 
 condition designated parasitism. The animal which thrives 
 by feeding on the living blood or tissue of another called 
 the host is a parasite. Parasitic animals are found among 
 nearly all the subkingdoms, but they are the most numer- 
 ous among the protozoans, worms, and arthropods. Only 
 about a dozen species of vertebrate parasites are known. 
 They are the lamprey eels (Fig. 215) and hagfish, which 
 
324 
 
 ANIMAL LIFE 
 
 FIG. 363. Photograph from life of the mouth of 
 the lamprey eel sucked fast to a piece of glass. 
 Natural size. 
 
 become the guests of 
 other fish whose blood 
 and mucus they suck 
 by attaching to their 
 sides. 
 
 Parasitic Protozoa. 
 Among the Proto- 
 zoa, the commonest 
 parasites are the 
 Amoeba dysenterica, in- 
 habiting the intestine 
 of man and causing 
 one kind of dysentery; 
 the Plasmodium malarice, residing in the human blood 
 corpuscles and producing malarial fevers; the Opalina, 
 of which hundreds 
 are present in the 
 large intestine of 
 the frog, and the 
 Gregarina, abun- 
 dant in the alimen- 
 tary canal of the 
 earthworm, lob- 
 ster, and many 
 beetles. 
 
 Parasitic Worms. 
 Of parasitic 
 worms there are 
 more than a hun- 
 dred species, most 
 of which live at the 
 
 FIG. 364. The malarial parasite photographed 
 through a microscope magnifying one thousand 
 diameters. Two individuals are present in the 
 red blood corpuscles. 
 
PARASITISM 
 
 825 
 
 expense of the vertebrates. The most dreaded of the round 
 worms is the Trichina living in the flesh of hogs, rats, dogs, 
 and man. One animal becomes infected by eating the flesh 
 of another containing the parasites which upon reaching 
 the stomach of the new host bring forth many 
 young ones. These migrate through the 
 walls of the alimentary canal into the mus^ 
 cles and remain there in a living condition 
 many months, never again becoming active 
 until eaten by a new host. The government 
 meat inspectors have found as many as 
 seventeen thousand hogs containing this par- 
 asite in one year. A microscopic worm, 
 Filaria, occurring in the blood of man in the 
 tropical regions, produces various disorders. 
 Among the larger parasites is the stomach 
 worm, Ascaris lumbricoides, from three to six 
 inches long, affecting children, and various 
 other species of Ascaris are common in nearly 
 all mammals. They hold on to the mucous 
 coat of the stomach or intestine by means 
 of a hook at the hind end, and feed on the 
 digested food. Eggs are produced at the rate 
 of about fifteen thousand daily, and passing 
 out with the excrement may reach the water 
 supply and infect new individuals. Strongylus is a genus 
 containing many species of minute, round worms parasitic 
 in the mammals, birds, and frogs. Some kinds occupy 
 the digestive system while others are present only in the 
 respiratory organs. Nine out of every ten cats harbor 
 round worms of some kind. 
 
 FIG. 365. Tri- 
 china. 1, fe- 
 male ; 2, male. 
 Enlarged fifty 
 times. 
 
826 
 
 ANIMAL LIFE 
 
 The flat worms are parasitic in all classes of vertebrates. 
 The liver fluke, annually causing the death of thousands 
 of sheep in Great Britain and South America, inhabits the 
 bile ducts in its adult stage, while during its early develop- 
 ment it swims free in the water and later becomes para- 
 sitic in the pond snail. After a time it escapes from the 
 snail and becomes encysted on a grass blade, where it re- 
 mains until eaten by the sheep. 
 
 The tapeworms, various species of which inhabit the ver- 
 tebrates from fish to man, attain the largest size of any of 
 
 the parasites, speci- 
 mens having been 
 reported over fifty 
 feet in length. They 
 are characterized by 
 a small head (scolex) 
 bearing hooks or 
 suckers for anchor- 
 age in the wall of 
 the alimentary tract, 
 a tapelike body com- 
 posed of numerous 
 segments, called 
 proglottides, and 
 the absence of a 
 digestive canal. They are nourished by the absorption 
 through their body walls of the digested liquid food of 
 the smaller intestine. The eggs, which the worms mature 
 by the thousands daily, can not develop within the host, 
 but pass out, and upon being taken in with food or drink 
 by certain animals hatch into spherical forms with six 
 
 FIG. 366. A tapeworm from the cat. h, head; 
 p t posterior end. Nearly life size. 
 
PARASITISM 
 
 327 
 
 hooks. Very soon each one migrates from the alimentary 
 canal to the muscles, liver, or peritoneum, and forms about 
 itself a sac or cyst, and is then known as a cysticercus. 
 Before any further growth can occur it must reach the 
 alimentary canal of the same species as that in which 
 its parent lived. Tcenia solium, a tapeworm occasionally 
 present in man, passes its larval stage in the flesh of the 
 pig, while the cysticercus of the other human tapeworm 
 is found in beef. In 
 some regions one out 
 of every five rabbits 
 contains the cysticerci 
 of the dog's tapeworm 
 in the liver or perito- 
 neum. They are oval 
 white bodies from a 
 fourth of an inch to 
 half an inch in diam- 
 eter. It is also quite 
 easy to find the cysti- 
 cerci of the cat's tape- 
 worm in the liver of 
 the mouse. 
 
 Parasitic Arthropods. 
 - The protozoans and 
 worms are all internal 
 parasites, but among 
 the arthropods are 
 found both internal and external feeders. To the latter 
 group belong most of the mites and ticks of the class 
 Arachnida. The hair mite (Fig. 150) is common in 
 
 FIG. 367. The mite producing sheep scab. 
 Much enlarged. 
 
328 
 
 ANIMAL LIFE 
 
 human oil glands supplying the hair. The microscopic 
 itch mite buries itself beneath the skin and causes the 
 disease of itch. Several other species of mites affect the 
 domestic animals and cause the falling out of the hair 
 and other disturbances. 
 
 The cattle tick (Boophilus boms) affects the cattle of 
 the Southern states, Mexico, and Cuba. Like many 
 external parasites, it sometimes leaves one victim to 
 
 PIG. 368. The cattle tick, female and male. Much enlarged. After Howard. 
 
 attack another later, and in so doing transfers the germs 
 of disease from the sick to the healthy. The cattle tick 
 has thus been found to be the chief if not the only means 
 of spreading the fatal Texas fever among herds of cattle, 
 and it is on this account that all cows shipped north must 
 first pass through the dipping tanks of petroleum or other 
 insecticidal liquid. Several species of ticks affect the 
 domestic animals. 
 The lice, of which there are more than forty species 
 
PARASITISM 
 
 329 
 
 FIG. 369. Bed bug. Side view shows 
 the piercing beak. Photograph twice 
 life size. 
 
 living on birds and mammals, differ from the true mites 
 and ticks in having only three pairs of legs, and the body 
 is divided into three parts characteristic of all insects. 
 Because of their parasitic habits the wings have been lost. 
 They secure their food by sucking the blood or by feeding 
 on the hair and feathers. 
 Only three species affect 
 man. 
 
 The bedbug and many 
 of the flies are what may 
 be termed temporary para- 
 sites as they are present 
 on the host only at inter- 
 vals. Among the fleas, 
 Pulex irritans is the one 
 annoying the dog, cat, and man. The eggs are often 
 laid on the hair of the cat or dog and the slender wrig- 
 gling larvae live in the 
 dirt filling the cracks 
 of the floor or similar 
 places. The female of 
 several species of mos- 
 quitoes attacks all warm- 
 blooded animals and 
 often conveys to man 
 serious diseases, such as 
 malaria, filariosis and 
 yellow fever. 
 
 Many insects are parasitic during their larval life, but 
 independent during the adult stage. The larvae of several 
 species of botflies dwell during the larval state either in 
 
 FIG. 370. Cat and dog flea enlarged fifteen 
 tim es . After Howard. 
 
330 
 
 ANIMAL LIFE 
 
 the alimentary canal or just beneath the skin of the mam- 
 mals. The young of the horse bot dwell in the stomach, 
 
 FIG. 371. Anopheles, the parasitic mosquito, infecting man with the malaria 
 germ. Photograph enlarged three times. 
 
 while those of the cow migrate, as soon as hatched, from 
 the alimentary canal to the back, just beneath the skin, 
 through which they make holes to 
 breathe and later escape. 
 
 All of the ichneumon flies, of 
 which there are more than a thou- 
 sand species, are parasitic in other 
 insects during the larval state. 
 Their presence usually means death 
 to the host. . They are, therefore, 
 of great service in keeping in check harmful species, such 
 as the cabbage worm, tussock moth, fall webworm, and 
 cotton caterpillar. Out of a hundred larvae of moths and 
 
 FIG. 372. Larva of the ox 
 bot (warble) removed from 
 beneath the skin of the back. 
 Photograph life size. 
 
PARASITISM 
 
 881 
 
 FIG. 373. Larva of the Catalpa sphinx moth frdm which are issuing the larva* 
 of ichneumon flies. The Avhite ovoid bodies are the cocoons in which the 
 larvae transform to adults. Over a hundred parasites were present in this host. 
 Photograph about life size. 
 
 butterflies collected in late summer or autumn nearly one 
 half will usually be found to contain the parasites of 
 either the ichneumon or chalcis flies. 
 
 The chalcis flies are small, and some species deposit 
 their eggs on the skin instead of within the insect, and 
 
 FIG. 374. Thalessa, an ichneumon inserting its two-inch ovipositor in a beech tree 
 to lay an egg in the burrow of the horn tail, a wood borer upon which the young 
 ichneumon will feed. The two curved hairlike supports steady the ovipositor. 
 Photograph. 
 
332 
 
 ANIMAL LIFE 
 
 FIG. 375. Five larvae of a chalcis fly in a bunch on a caterpillar. Photograph 
 nearly twice life size. 
 
 certain species parasitize the eggs of the harmful insects, 
 thus rendering great service. Tachina flies aid in the 
 good work also. Their minute eggs are 
 glued to the skin of the host separately 
 (Fig. 26). 
 
 In cases where the young live an in- 
 dependent life and the adults are para- 
 sites, marked degeneration often occurs, 
 which is especially noticeable among the 
 crustaceans. Sacculina exhibits in youth 
 the characteristic features of its order, but 
 after becoming a parasite on the crab in 
 later life, the legs, eyes, and mouth parts are entirely lost 
 and it absorbs nourishment from its host by numerous del- 
 icate, rootlike suckers. Other peculiar crustaceans, known 
 
 FIG. 370. -A Tachin 
 fly- Photograp 
 
 slightly enlarged. 
 
PAKASITISiM 
 
 833 
 
 as fish lice, live as parasites attached to the gills or ex- 
 ternal surface of fish and other aquatic forms. Of these the 
 Lerneans are most remarkable in respect to degeneration. 
 They occur on all aquatic creatures from the coelenterates 
 and echinoderms to the whales. Out of a dozen codfish 
 I examined on the Maine coast, eight contained one or 
 
 FlG. 377. Nauplius or larva 
 ofLernea branchialis. Pho- 
 tographed through the micro- 
 scope. 
 
 FIG. 378. Adult female Ler- 
 nea branchialis. The 
 branched process at the left 
 enables it to hold fast in the 
 gills. Photograph life size. 
 
 more individuals of Lernea branchialis embedded in the 
 gills. The male of this species leads an independent life. 
 This brief discussion of parasites shows that but few, 
 if any, of the species above the protozoa are exempt from 
 having their bodies made the feeding ground for smaller 
 creatures. If certain species of insects occur in vast 
 numbers one season, few will be present the following 
 year owing to destruction by parasites. The life of these 
 paupers means death to many of their hosts, and so large a 
 part do they play in the world of physical life that Dr. 
 Smith says, " Without them there would be no possibility 
 of an existing vegetation." 
 
334 ANIMAL LIFE 
 
 24. VANISHING SPECIES 
 
 The fossil remains of animal life embedded in the rocks 
 testify that more than fifty thousand species have vanished 
 within probably thirty million years. The stone records 
 indicate that during the ancient past no one species sur- 
 vived longer than two or three million years, while some 
 may have existed only a few thousand years. In the 
 earth's youth, the comparatively rapid changes in climate, 
 soil, and food, together with the appearance of new ene- 
 mies, made it necessary that any species to win in the 
 struggle for existence should change its habits and struc- 
 ture to harmonize with its environment. The penalty for 
 failure to do this was extinction. There is a continual 
 warfare in nature not only between certain different species, 
 but also among the individuals of the same species. Of 
 the one hundred or more spiders hatched from the eggs in a 
 cocoon only a few attain full size, the weaker being eaten 
 by the stronger. Of the million eggs deposited by a shad, 
 probably less than a score give rise to adults, as many will 
 die from lack of food and others must go to satisfy the 
 carnivorous appetite of larger fish. Of a dozen quail 
 reared in a single nest, only a few of the more hardy and 
 wideawake will be able to endure the rigorous winter and 
 escape the ever-pursuing enemies. The fulmar petrel is 
 one of the most abundant of birds in certain regions of the 
 seas, but the female lays only one egg yearly. It has 
 scarcely any enemies. Rabbits, though producing three 
 litters of from four to six each in a season, are on the de- 
 crease in the Eastern States, owing to the presence of 
 
VANISHING SPECIES 335 
 
 so many foxes, dogs, mink, men, and raptorial birds. In 
 the Western States the rabbits have lately increased 
 to such an extent that public drives or hunts are arranged, 
 by which as many as twenty thousand are taken in a single 
 day. This increase is due to the fact that the wolves and 
 coyotes, which formerly preyed on the rabbits, have year 
 by year had their ranks lessened by the shotgun, the trap, 
 and poisoned bait. In parts of New Zealand, where car- 
 nivorous animals are few, the imported rabbits have multi- 
 plied to such an extent as to consume all the grass, thereby 
 causing the sheep to starve to death. Thus the ascendency 
 of one group of animals often means the disappearance of 
 another. This is especially true of the introduction of a 
 parasite into a new country where the hosts have not be- 
 come more or less adapted to withstanding its attacks. 
 The smallpox germ introduced into Iceland in 1734 killed 
 more than half the population, and almost equally fatal 
 results occurred when the disease first visited Greenland. 
 
 It is therefore evident that the extermination of a species 
 depends on several factors, most important of which are 
 the presence of numerous enemies and the lack of proper 
 food. During the age of man, including perhaps not much 
 over a hundred thousand years, several species of verte- 
 brates have become extinct, among which are the huge 
 mammoth (a near relative of the elephant), Steller's sea 
 cow, the great auk, and the moas or giant birds of New 
 Zealand. 
 
 In 1871 Colonel Dodge drove for twenty-five miles along 
 the Arkansas River through an unbroken herd of buffalo. 
 Millions of these noble animals fed on the western plains. 
 A few years later the completion of the Northern Pacific 
 
336 
 
 ANIMAL LIFE 
 
 FIG. 379. The mammoth, the ancestor of the elephant. From a painting by 
 Knight in the American Museum of Natural History. 
 
 Railroad brought the hide hunter to the grazing grounds, 
 and by 1883 scarcely a thousand buffalo were in existence. 
 Congress has many times failed to do its duty in enacting 
 proper laws for the preservation of our animal wealth. 
 
 Until a half century ago moose were abundant in the 
 Adirondacks and many other wooded regions in the north- 
 ern states, but the ceaseless slaughter continuing for years 
 unchecked has exterminated the species in most of the 
 states except Maine, Wyoming, Idaho, and Minnesota. 
 The prong-horned antelope has been saved from utter 
 destruction in most of the states it inhabits by the enact- 
 ment of proper laws. In Routt County, Colorado, it is 
 estimated that only about fifty antelope survive, while 
 fifteen years ago there were nearly fifty thousand. In the 
 
VANISHING SPECIES 
 
 337 
 
 same State, the mule deer is said also to be on the verge of 
 extinction. Any animal valuable for flesh, fur, or feathers 
 is destined to be one of the vanishing species unless pro- 
 tected by law from its great enemy, man. The beaver, 
 celebrated for its architectural 
 skill and intelligence, has fled 
 from most of its former haunts in 
 the Eastern and Middle States, 
 and now exists only in small 
 numbers from the Rio Grande 
 in Texas northward to the limit 
 of trees, and southeastward 
 through Canada to New' Eng- 
 land. The fur-bearing Alaska 
 sea lion, wrongly called seal, 
 which for many years furnished 
 more than a million dollars' 
 worth of sealskin annually, will 
 within another decade become 
 so few as to be of little com- 
 mercial value unless the killing of mothers at sea is 
 stopped. In 1873 a special agent of the government esti- 
 mated the number of seals living on the Prib'ilof Islands 
 to be over three millions. In 1890 the number was con- 
 sidered to be less than one million, and in 1903 a careful 
 investigation showed that only about two hundred thou- 
 sand were yet living. 
 
 Not only mammals, but likewise birds and fish, are van- 
 ishing before the terrific slaughter of man. The woodcock, 
 wild turkey, prairie chicken, and wild pigeon abounded in 
 many regions a quarter of a century ago. To-day the 
 
 FIG. 330. The buffalo (bison). 
 Photographed in the Philadel- 
 phia Zoological Gardens. 
 
338 ANIMAL LIFE 
 
 woodcock have deserted entirely many of their former 
 feeding grounds east of the Mississippi, and are scarce 
 everywhere. The wild turkey survive only in a few heavily 
 timbered regions in Florida, Virginia, Pennsylvania, Texas, 
 and perhaps one or two other States. The prairie chicken, 
 once so numerous on the western plains, can not last much 
 beyond another decade, and the wild pigeon was thought 
 to be practically extinct in 1899, but a few scattered flocks 
 have since been discovered. The enormous numbers of 
 pigeons present in the Eastern States forty years ago is 
 clearly shown by Audubon's description of them as ob- 
 served in Kentucky. 
 
 " Let us now inspect the places of nightly rendezvous. 
 . . . My first view of it was about a fortnight subsequent 
 
 FIG. 381. The wild pigeon (Ec-topisteus migratorius). Photographed in the 
 Academy of Natural Sciences, Philadelphia. One sixth life size. 
 
 to the period when they had made a choice of it. ... As 
 the period for their arrival approached, their foes anxiously 
 prepared to receive them. . . . The sun was lost to our 
 view, yet not a dozen had arrived. Everything was ready, 
 
VANISHING SPECIES 339 
 
 and all eyes were gazing on the clear sky, which appeared 
 in glimpses through the tall trees. Suddenly there burst 
 forth a general cry, ' Here they come.' . . . Thousands 
 were soon knocked down by the pole men. The birds 
 continued to pour in. The fires were lighted and a magnifi- 
 cent as well as wonderful and almost terrifying sight pre- 
 sented itself. The pigeons arrived by thousands, alighted 
 everywhere, one above another, until solid masses as large 
 as hogsheads were formed on the branches all around. 
 Here and there the perches gave way under the weight 
 with a crash, and falling to the ground destroyed hundreds 
 of birds beneath, forcing down the dense groups with which 
 every stick was loaded. It was a scene of uproar and 
 confusion. I found it quite useless to speak or even to 
 shout to those persons who were nearest to me. Even 
 the reports of the guns were seldom heard, and I was made 
 aware of the firing only by seeing the shooters reloading. 
 
 " No one dared to venture within the line of devasta- 
 tion. . . . The pigeons were constantly coming, and it 
 was past midnight before I perceived a decrease in the 
 number of those that arrived." 
 
 The investigations of Hornaday, as cited in a previous 
 chapter, show that many species of birds are being so per- 
 secuted by the egg hunters, the small boy, and the cat, 
 that their numbers have been lessened one half within 
 fifteen years, and soon we may expect several species to 
 become extinct unless through education public sentiment 
 is changed. 
 
 The supply of alligators has decreased about ninety- 
 eight per cent since fashion smiled on belts, pocket-books, 
 and hand bags made of alligator hide. If the demand for 
 
340 ANIMAL LIFE 
 
 tortoise-shell articles continues on the increase another 
 decade or two, the hawkbill turtle will share the fate of 
 the buffalo. The salmon, trout, and lobster, once supply- 
 ing millions of dollars' worth of fine food annually, are 
 reported to be decreasing in an alarming manner owing to 
 the recklessness with which lax laws permit them to be 
 caught. Of the twenty-eight rivers formerly inhabited 
 by the salmon, only eight now contain them, and in one 
 district where in 1896 three hundred thousand cases of 
 
 FIG. 382. The brook trout. 
 
 salmon were put up, scarcely any fish were taken three 
 years later. While the brook trout will probably always 
 be cultivated in ponds, where its finer qualities degener- 
 ate, there is scarcely a possibility of its continuance in the 
 unprotected forest streams longer than a decade or two. 
 
 The government authorities of the various states as well 
 as of the United States within recent years have become 
 aware of the fact that in order to preserve the vast wealth 
 of our country represented by wild animal life, stringent 
 protective laws and an enlightened public sentiment must 
 be created. The recreation and sport afforded by the 
 legitimate hunting of wild game is a great conserver of 
 
VANISHING SPECIES 341 
 
 FIG. 383. The lobster. Photograph one fifth life size. 
 
 nervous energy, and when statistics show the millions of 
 dollars bound up in the untamed fish, fowl, and beast, 
 there can be no doubt about the wisdom of spending a 
 large amount of money to maintain this wealth in forest 
 and stream. The value of our fish products annually is 
 fully fifty million dollars. The annual government appro- 
 priation for the maintenance of the fish industry is a half 
 million dollars. From July, 1901, to July, 1902, the bureau 
 of fisheries distributed eggs and young fish to the number 
 of 1,414,523,374. In addition, 81,020,000 young lobsters 
 were planted in favorable localities along the seacoast. 
 Thus by the aid of the State and the United States Fish 
 Commissions hundreds of streams have been stocked with 
 trout, bass and other game fish, and lobster fishing has 
 been made a productive industry in many regions along 
 the coast. 
 
 When boys and girls as well as men and women realize 
 that every act tending toward the preservation of our bene- 
 ficial wild animals manifests true patriotism, history will 
 record a full century without the extinction of a single 
 valuable species of animal life. 
 
342 ANIMAL LIFE 
 
 25. ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 
 
 A study of the universe and of the rocks forming the 
 crust of the earth shows that conditions were such many 
 millions of years ago that no life could have existed on this 
 planet. It is therefore evident that living things at some 
 time in the past must either have been developed from life- 
 less material or reached the earth from some other heavenly 
 body. Scientists find no evidence in favor of the latter 
 theory, and we are therefore forced to believe that at some 
 period after the surface of the earth became cool, spon- 
 taneous generation occurred, i.e., a particle of lifeless earth 
 was transformed into a living thing. 
 
 The conception of the ancient as well as some of the 
 more modern philosophers in regard to the origin of animals 
 is entirely erroneous. Aristotle held that some animals 
 spring from putrid matter, that certain insects develop 
 from dew, that worms originate in the mud of wells, that 
 fleas arise from very small portions of corrupted matter, 
 and bugs proceed from the moisture on animal bodies, and 
 lice from the flesh of other creatures. Van Helmont, of 
 the seventeenth century, gives detailed directions for 
 creating mice out of wheat and stagnant water. The 
 learned Alexander Ross, about the year 1700, declares 
 there is no doubt that worms are generated from cheese 
 and that butterflies, locusts, grasshoppers, snails, eels, and 
 such like originate from putrid matter. 
 
 Before the days of the compound microscope and care- 
 ful scientific research, spontaneous generation was thought 
 to be going on continually, but by numerous carefully con- 
 ducted experiments of Spallanzani, Schultze, Schwann, 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 343 
 
 and Pasteur it was demonstrated about fifty years ago that 
 spontaneous generation does not occur under present con- 
 ditions in this world. All animals originate from their 
 parents by means of fission, spore formation, budding, or 
 
 FIG. 384. Amoeba showing formation of two animals from one by fission. 
 
 eggs. Fission, consisting in the division of the animal 
 into two parts, is common among the Protozoa and occurs 
 in a few species of worms. Spore formation may be seen 
 in some of the Protozoa, such as the malarial parasite, in 
 which case the animal forms a cyst or thick coat around 
 
344 
 
 ANIMAL LIFE 
 
 itself and divides into several fragments. The cyst then 
 burst, and each fragment or spore becomes a separate 
 animal. As noted in a previous chapter, budding takes 
 place in the hydra and many other coelenterates and in a 
 fow worms. Reproduction by eggs occurs in all species 
 
 above the protozo- 
 ans. The eggs and 
 spores of some of 
 the microscopic ani- 
 mals are so small 
 as to require very 
 high magnifying 
 power to define them 
 clearly, and when 
 dry are capable of 
 
 inthe air by currents 
 
 thereby gaining access to open vessels of water or other 
 fluids suited to their development. Until fifty years ago 
 people thought that broth or milk boiled in an air-tight 
 jar sometimes spoiled because particles of the materials 
 were transformed into minute living bodies. At present 
 it is well understood that the life in the sealed and heated 
 jars was due to minute germs or spores of plant life, called 
 bacteria, some of which are not killed by being boiled a 
 half hour. 
 
 Up to the present time nearly a half million different 
 kinds or species of animals have been described, and more 
 than a hundred new species are discovered every year, so 
 that it is probable that there are no less than a million 
 species of animals dwelling on this planet. That a pair of 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 345 
 
 each of these was created direct from lifeless material seems 
 very improbable, though until 1859, when Charles Darwin 
 published his " Origin of Species," this was generally be- 
 lieved. The Bible describes briefly the creation of the 
 various groups of 
 animals on several 
 successive days. 
 These days instead 
 of being twenty- 
 four hours, as for- 
 merly understood, 
 are now considered 
 to have been long 
 periods of time, 
 each equaling sev- 
 eral million years. 
 The earth's surface 
 was once entirely 
 covered with water 
 holding in solution 
 or suspension large 
 quantities of min- 
 eral matter, which settling to the bottom from time to time 
 hardened into strata (layers) of rock. The skeletal portions 
 of the animals dying also dropped to the bottom, and oft- 
 times left the indelible impressions of their bodies in the 
 forming rock, or the skeletal structure was itself replaced 
 with stone (fossilized). By contraction of the earth's crust 
 certain portions were forced up out of the water and made 
 ready for habitation by land animals. These coming to the 
 water to drink or rushing into the lakes to escape from their 
 
 FIG. 386. Bacteria causing consumption (tubercu- 
 losis) ; six or seven germs resembling minute rods 
 are present. Photograph magnified one thousand 
 diameters. 
 
346 
 
 ANIMAL LIFE 
 
 enemies sometimes perished, and their skeletons were like- 
 wise entombed in the sediment-forming rock and there 
 became fossilized. Therefore, each successive stratum or 
 layer of rock containing the remains of the life of former 
 ages serves as the leaf of a book giving a description of the 
 
 animate world be- 
 fore the era of man. 
 By careful compu- 
 tation scientists 
 have determined 
 that life has proba- 
 bly existed on the 
 earth for a period 
 of from twenty mil- 
 lion to one hundred 
 million years. The 
 fossil remains show 
 that the inverte- 
 brates lived here more than a million years before there 
 were any vertebrates; the fish preceded the amphibians 
 by several million years, while as much more time elapsed 
 before the advent of reptiles, which dwelt here at least 
 two or three million years before the appearance of birds. 
 There is evidence indicating that man has been on the 
 earth from fifty thousand to a hundred thousand years, 
 and it is possible that he has been here even a million 
 years. 
 
 " From lower to higher, 
 From simple to complete, 
 This is the pathway of eternal feet ; 
 From earth to lichen, 
 
 FIG. 387. A piece of rock containing the fossil re- 
 mains of several animals. Photographed in Am- 
 erican Museum of Natural History. 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 84? 
 
 From herb to towering tree, 
 From cell to creeping worm, 
 From man to what shall be ; 
 This is the lesson of all time, 
 This is the teaching of the voice sublime." 
 
 The sequence of forms in the successive rock strata 
 makes it evident that under the stress of a rapidly changing 
 environment certain individuals of a species changed in 
 habit and structure so as to persist in the struggle among 
 
 FIG. 388. Photograph of the fossil feet of three-toed horses iu the Museum of 
 Natural History. 
 
 associates for food, and thus gave origin to a new variety 
 or kind of animal, while those of the species which did not 
 change to a more advantageous habit and structure be- 
 came extinct. For instance, records clearly show that the 
 
B48 ANIMAL LIFE 
 
 ancestor of our horse was a three-toed uigulate scarcely 
 larger than a sheep and with teeth adapted to feed on succu- 
 lent vegetation, such as the warm, moist climate of those 
 early days afforded. As the ground, then wet and swampy, 
 became hard, and the juicy vegetation gave way to the 
 dryer grasses, the lateral toes became shorter in certain 
 
 FIG. 389. Skeleton of Mesohippus bairdi, the three-toed ancestor of our horse. 
 This animal was about the size of a sheep. After Farr. 
 
 individuals, and the third digit grew longer and stronger, 
 thus enabling them to escape their carnivorous pursuers, 
 while all those individuals whose limbs and teeth did not 
 vary so as to aid them to escape the increasing carnivorous 
 animals and masticate the dry grasses, were exterminated. 
 Thus age after age those horses whose lateral toes became 
 smaller while the third one grew longer, giving them greater 
 speed, persisted and multiplied, but those with large, lateral 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 349 
 
 toes as an encumbrance fell prey to 
 their pursuers. This process of de- 
 veloping new species is called evolu- 
 tion by variation and natural selection. 
 The ancestor of the three-toed horses 
 were four-toed animals whose remains 
 are found in the layers of rock be- 
 neath those containing the three-toed 
 ones. By this process of variation 
 and natural selection the four-toed 
 forms were derived from a five-toed 
 mammal with such a generalized FIG. 390. -Photograph of 
 
 t foot of four-toed horse 
 
 Structure that Other Of itS progeny in American Museum of 
 
 Natural History. 
 
 developed into sheep, cows, and deer 
 
 in accordance with the various foods and changing factors 
 
 FIG. 391. After Matthews in Guide Leaflet of American Museum of Natural History. 
 
350 
 
 ANIMAL LIFE 
 
 in nature to which they were subjected. Thus, by varia- 
 tion and natural selection numerous and widely different 
 kinds of animals arose. 
 
 Variation in the individuals of certain species, and there- 
 fore evolution, is occurring at the present time, but much 
 
 Fro. 392. The four-toed horse restored from a study of its fossil skeleton. From 
 Guide Leaflet of the Museum of Natural History, New York. 
 
 more slowly than during the world's infancy, when climate, 
 food, and other factors were changing more rapidly. An 
 observer, seeing for the first time the very dark and very 
 light forms only of the Catalpa caterpillar, would at a 
 glance declare them two different species, but after find- 
 ing specimens with all the gradations in shade from light 
 to dark (Fig. 394), he would be forced to consider the two 
 unlike individuals to belong to the same species. If, in the 
 future, the four intervening forms shown in the figure be- 
 come extinct and the adults of number one and number 
 six differ as widely as the larvse and remain constant in 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 351 
 
 their characteristics, scientists would be warranted in 
 recognizing the two forms as separate species. 
 
 A species of moth of the genus Saturnia, brought from 
 Texas to Switzerland, where the young fed on the European 
 
 PIG. 393. The Mastodon, an early ancestor of the elephant and long since extinct. 
 From a painting by Knight in the American Museum of Natural History. 
 
 walnut, presented after one generation such marked differ- 
 ences from the same species whose young fed in Texas on 
 the black walnut, that entomologists gave it a new name. 
 The brine shrimp, Artemia salina, lives in slightly brackish 
 water, while Artemia milhauseni occurs only in very salt 
 water. If salt be gradually added to the vessel containing 
 the former species, it will in a few generations during the 
 months of a single summer, transform into the latter species. 
 Likewise, Artemia milhauseni will, in a few months, change 
 
352 
 
 ANIMAL LIFE 
 
 into Artemia saUna upon the gradual addition of fresh 
 water. The crustaceans and fish of the Mammoth Cave, 
 though differing greatly in certain features from the forms 
 
 FIG. 394. Variation in the Catalpa caterpillar. Photograph natural size. 
 
 in the waters just outside, give unmistakable evidence of 
 being their direct descendants. 
 
 Other evidences of evolution are furnished by rudimen- 
 tary structures, which are present in all of the higher verte- 
 brates. Some of the lizards, having only one pair of legs, 
 have rudiments of the other pair beneath the skin. The 
 rudiments of the hind legs in the Python are apparent ex- 
 ternally. No functional hind limbs are present in any of 
 the whales, but several species possess small structures 
 
ORIGIN OF THE DIVERSE FORMS OF ANIMAL LIFE 853 
 
 beneath the skin in the position of the hind limbs. Teeth 
 are present in the jaws of the whalebone whales, but they 
 never appear above the surface, and 
 the young of the ruminants have 
 buried in the gums minute upper 
 incisors, though they do not de- 
 velop into functional teeth in the 
 adults. The vermiform appendix, 
 occurring in man and the anthro- 
 poid apes, is of no use, but in their 
 ancestors it may have played an 
 important part in digestion, as the 
 corresponding portion of the ali- 
 mentary canal does yet in the rab- 
 bit, groundhog, and other forms. 
 The splint bone, about ten inches 
 long on either side of the lower part 
 of the horses' limb, serves no useful 
 purpose now. All of these useless 
 structures clearly indicate that they 
 were of larger size in the far-off an- 
 cestors in whom their presence was 
 of great use. 
 
 Still further testimony, favoring 
 a belief in evolution, is given by the 
 study of Embryology which deals 
 with the development of the young 
 from the egg. In very young stages the higher verte- 
 brates are seen to resemble the adult forms of some of the 
 lower animals. The chick, when taken from an egg 
 incubated for three days, is found to have gill slits and 
 
 FIG. 395. Skeleton of the 
 fore limb of the horse. 
 sc, shoulder blade ; h, hu- 
 merus ; r, radius ; ua, 
 ulna; m 3 , third metacar- 
 pal; m 4 , splint bone or 
 fourth metacarpal ; p t 
 phalanges. From Davi- 
 son's " Mammalian Anat- 
 omy." 
 
354 
 
 ANIMAL LIFE 
 
 gill arches and an entire circulatory system, strikingly 
 similar to the same structures in the fish. The brain is 
 fishlike also. In some young birds taken from the egg, 
 
 FlG. 396. Fore limbs of vertebrates showing similarity of structure. A, sala- 
 mander ; B, turtle ; C, very young bird ; Z>, adult bird ; E, dog ; F, man. 
 
 the wing strongly resembles in structure the limb of a 
 lizard. 
 
 These facts, cited in the preceding paragraphs together 
 with much other information discovered by the zoologist 
 and geologist, lead to the conclusion that at first there 
 existed on earth only a few forms of simple life similar to 
 the amoeba, and from these acted on by the rapid changes 
 of climate, soil, water, and food, have arisen all the varied 
 forms of animal life. 
 
INDEX AND GLOSSARY 
 
 Adaptations, 311-323. 
 
 Adder, 214, 216. 
 
 Air bladder, 196, 198. 
 
 Air sacs of birds, 227. 
 
 Alligator, 221, 339. 
 
 Alternation of generations, 172, 
 
 173. 
 
 Amblys'toma, 200, 201, 302. 
 Ambula'cral, 162. 
 Ameiu'rus, 190. 
 Ammocoe'tes, 186, 300. 
 Amoa'ba, 179-182, 324. 
 Amphib'ia (Gr. amphi, both, and 
 
 bios, life), 27, 199-211. 
 eggs of, 294-296. 
 Anaconda, 220. 
 Anat'omy, 11. 
 Anem'one, 174. 
 Angle worms, 152-154. 
 Anguillu'la, 155. 
 Animalcule, a minute animal, 
 
 178, 180. 
 Annulat'a (L. annulus, ring), 25, 
 
 150-154. 
 Anodont'a, 143. 
 Ano'lis, 212. 
 Anoph'eles, 41, 42, 182. 
 Ant-eater, 263, 264. 
 Antelope, 336. 
 Anten'nae, 32, 68, 120, 307. 
 Anthon'omus, 108, 109. 
 Anthrenus, 113, 114. 
 Anthropoid apes, 281. 
 Ant-lion, 117. 
 Ants, 24, 56-57. . 
 
 cows of, 98. 
 Anu'ra, 204. 
 
 Apes, 281. 
 
 Aph'idse, 95. 
 
 Aphis, 97. 
 
 Apple tree borer, 24, 111. 
 
 worm, 87. 
 
 AquaVic, dwelling in the water. 
 Aquaria, 19. 
 Ar&ch'nida (Gr. arachne, spider) < 
 
 26, 125-132. 
 Arbac'ia, 164. 
 Archaeop'teryx, 227. 
 Argi'ope, 130. 
 Armadillo, 264. 
 Armored scales, 103. 
 Army worm. 24, 48, 85. 
 Arte'mia, 351. 
 Ar throp' o da (Gr. arthron, joint 
 
 and poda feet), 26, 30-40. 
 
 parasitic, 327-333. 
 Ascaris, 325. 
 Asparagus beetles, 24. 
 Aspidiotus, 98-102. 
 Assassin bugs, 105. 
 Aste'rias, 161-165. 
 Audubon society, 24. 
 Auricle, the cavity of the heart 
 
 which receives the blood, 
 
 289. 
 
 Aves, 27, 226-261. 
 Ax'olotl, larva of the Ambly- 
 
 stoma mexicanum, 209, 302. 
 
 Baboons, 281. 
 Bacteria, 344, 345. 
 Baltimore oriole, 24, 235. 
 Bark beetle, 24, 109. 
 Bark lice, 98-104. 
 
 355 
 
356 
 
 INDEX AND GLOSSARY 
 
 Barnacles, 139, 140, 299. 
 Bats, 273, 274. 
 Bead snake, 216. 
 Beans, insects affecting, 278, 279. 
 Bear, 278, 279. 
 Beaver, 337. 
 Bee, eye of, 310. 
 Bee keeping, 23. 
 Bee martin, 232. 
 Bees, 52-55. 
 Beetles, 107-115. 
 Bedbug, 24, 104. 
 Bell animalcule, 180. 
 Beneficial insects, 47, 48, 51-56. 
 Bl'nary fission, a method of re- 
 production in which the or- 
 ganism divides into two equal 
 parts, 179, 182. 
 Bi61'ogy, the study of plant and 
 
 animal life, 11. 
 Bird day, 24. 
 
 Bird, external features, 229. 
 Birds, 226-261. 
 
 decrease in, 227. 
 
 destruction of, 255-257, 339. 
 
 eggs of, 234. 
 
 food of, 24. 
 
 in relation to insects, 258. 
 
 migration of, 24,. 260. 
 Bison, 266. 
 Blackbirds, 236. 
 Black crab, 116. 
 Black snake, 214, 216. 
 
 eggs of, 293. 
 Black swallowtail, 72. 
 Bladder worm, 159. 
 Blind crayfish, 141. 
 Blissus leucop'terus, 105. 
 Blowfly, 46. 
 Bluebird, 243, 248, 259. 
 Blue crab, 138. 
 Blue sharks, 188. 
 Boa constrictor, 220, 221. 
 Bobolink, 235. 
 
 Bobwhite, 318. 
 Boll worm, 23. 
 Bonibyc'idae, 74. 
 Bones of bird, 354. 
 
 of cat, 290, 291. 
 
 of dog, 354. 
 
 of horse, 266, 353. 
 
 of man, 354. 
 
 of salamander, 354. 
 
 of turtle, 354. 
 Bony fish, 189. 
 Borer, apple tree, 111. 
 
 locust, 111. 
 
 maple, 112. 
 
 peach tree, 89, 90. 
 
 pine tree, 112. 
 
 Borers, certain insect larvse, 
 mostly of beetles and moths, 
 dwelling in trees, 89. 
 Botflies, 48-50, 330. 
 Box tortoise, 222. 
 Brain of cat, 287, 288. 
 
 mammals, 290. 
 Breeding of amphibians, 207. 
 Brine shrimp, 351. 
 Brittle star, 166. 
 Brontosau'rus, 226. 
 Brush-footed butterflies, those 
 with imperfect and hairy fore- 
 legs, 69. 
 Buc'cal, 179. 
 Buffalo, 266, 335, 336, 337. 
 
 moth, 24, 113. 
 Bufo, 207. 
 Bugs, 91. 
 
 Bulletins and circulars of Agri- 
 cultural Department of U. S., 
 23, 24. 
 
 Bull frog, 205. 
 Bull head, 189. 
 Bumble bee, 54, 306. 
 Butterflies, 68-73. 
 Butterfly , protective resemblance, 
 313. 
 
INDEX AND GLOSSARY 
 
 357 
 
 Cabbage butterfly, 71. 
 fly, 47. 
 worms, 67, 72, 73. 
 
 Cabinets for insects, 17. 
 
 Caddis fly, 311. 
 
 Caeca (se ka) (L. ccecus, blind), 
 163. 
 
 Camel, 268, 271. 
 
 Canidae, 277. 
 
 Canker worms, two species of 
 moth larvae which destroy 
 the foliage of fruit trees, 24, 
 85, 86, 258. 
 
 Car'apace, the dorsal part of the 
 hard shell of crustaceans and 
 turtles, 133, 222. 
 
 Caribou, 267. 
 
 Carniv'ora (L. caro, flesh, and 
 voro, devour), 28, 275-280. 
 
 Carpet beetle, 24, 113. 
 
 Cartilaginous fish, 187-189. 
 
 Catal'pa caterpillar, 350, 352. 
 
 Catalpa moth, 47, 64, 65. 
 
 Catamount, 276. 
 
 Catbird, 240, 244, 258. 
 
 Caterpillar, the larva of a moth 
 or butterfly, 74. 
 
 Catfish, 189, 190. 
 
 Cats, 276. 
 
 Cattle, 266. 
 
 Cattle tick, 328. 
 
 Cave animals, 308. 
 
 Cave fishes, 192. 
 
 Cedar bird, 240, 242, 258. 
 
 Cell, a microscopic portion of 
 semifluid life-substance called 
 protoplasm, usually sur- 
 rounded by a thin membrane 
 and containing a nucleus, 
 178, 289, 293, 294. 
 
 Centiped, 18, 24, 132. 
 
 Cerambyc'idae, 111. 
 
 Ceta'cea (L. cetus, whale), 28, 
 264. 
 
 Chalcis flies, 67, 68, 331. 
 
 Chalk formers, 183. 
 
 Chameleon, 212. 
 
 Chatterers, 240. 
 
 Chelo'nia, 222-225. 
 
 Chickadee, 242, 258, 259. 
 
 Chimney swift, 244, 249, 250. 
 
 Chimpanzee, 282. 
 
 Chinch bug, 12, 105. 
 
 Chipmunks, 270. 
 
 Chipping sparrows, 238, 239. 
 
 Chippy, 238. 
 
 Chirop' ter a (Gr. cheir, hand, and 
 pteron wing), 28, 273, 274. 
 
 Ch lor 'e tone, a one per cent solu- 
 tion added to from five to 
 ten times as much water 
 renders aquatic animals un- 
 conscious, 21, 210. 
 
 Chloroform, 19. 
 
 Chrys'alid, the pupal stage of a 
 butterfly, 71. 
 
 Cica'da, 92-95, 298. 
 
 Clams, 142, 143. 
 
 Class, 26. 
 
 Classification of animals, 25-29. 
 
 Clavicorn beetles, 113. 
 
 Clear-winged moths, 89, 90. 
 
 Click beetles, 113. 
 
 Clothes moth, 24, 88, 89. 
 
 Clover seed midge, 61. 
 
 Clupea, 190, 191. 
 
 Cobra, 220. 
 
 Coc'cidae, 98. 
 
 Coccinel'lidaa. 114. 
 
 Cochineal insect, 103. 
 
 Cockroaches, 24, 38. 
 
 Co coon', the case formed of soil, 
 hair, silk, or other material, 
 in which many insects pass 
 the pupal stage, 77, 88, 90, 
 331. 
 
 Coddling moth, 23, 87, 88, 125 
 
 Codfishes, 193. 
 
858 
 
 INDEX AND GLOSSARY 
 
 Ccelenterata (se len' ter a'ta) (Gr. 
 koilos, hollow, and enteron, 
 intestine), 25, 167, 175. 
 
 Cceloine (se'lome), body cavity, 
 157, 168. 
 
 Cold-blooded animals, 196. 
 
 C5l e op' te ra (Gr. koleos, sheath, 
 and pteron, wing), 27, 107, 
 115. 
 
 Commen'salism, 177. 
 
 Condor, 249. 
 
 Congo snake, 203. 
 
 Conjuga/tion, a process of union 
 whereby protoplasm is trans- 
 ferred from one organism to 
 another, 180. 
 
 Cooper's hawk, 251, 253. 
 
 Copperhead, 218, 219. 
 
 Coral, 175. 
 
 Corn worm, 84. 
 
 Cotton boll weevil, 12, 23, 108. 
 
 worm, 84. 
 caterpillar, 68. 
 insects affecting, 23. 
 
 Cow bird, 236. 
 
 Coyotes, 277. 
 
 Crabs, 136-138. 
 
 Cranberries, insects affecting, 23. 
 
 Crane, 254. 
 
 Crane flies, 44. 
 
 Crawfish, 135, 136. 
 
 Crayfish, 135, 136. 
 
 Creation of animals, 342-354. 
 
 Cricket, 3G, 37. 
 
 Crinoids, 166. 
 
 Crocodilia, 221, 222. 
 
 Crotalidffi, 216. 
 
 Croton bug, 38. 
 
 Crows, 233, 235. 
 
 Crnsta'cea (L. crusla, crust), 26, 
 133-141. 
 
 Crustaceans, metamorphosis of, 
 299, 300. 
 
 Cryptobran'chus, 203. 
 
 Cuckoos, 247, 251, 258. 
 
 Cucumber beetles, 24. 
 
 Culex, 39, 41, 42, 44. 
 
 Curcu'lio, 107. 
 
 Currant saw fly, 58. 
 
 Cuttlefish, 149. 
 
 Cutworms, 82-84. 
 
 Cy'anide jar, 19. 
 
 Cyclpstom'ata, 185-187. 
 
 Cypris, 139. 
 
 Cysticercus (sis ti sur' kus) (Gr. 
 kystis, bladder, and kerkos, 
 tail), the larval stage of a 
 tape worm, 159, 296, 327. 
 
 Damsel flies, 119, 120. 
 Daphnia, 139. 
 Deer, 267, 268. 
 Desmognathus, 201, 203. 
 Diapherom'era, 314. 
 Diaphragm, 285. 
 Digitigrade. 266. 
 Digits, 265, 292. 
 Diaspis, rosse, 103. 
 Digestive system. 
 
 Cat, 285. 
 
 Crayfish, 134. 
 
 Fish, 197, 198. 
 
 Frog, 209. 
 
 Honey bee, 53. 
 
 Locust, 123. 
 Dipnoi, 185, 195. 
 Diplodocus, 226. 
 Drp'tera (Gr. di, two, and ptera, 
 
 wings), 27, 39-51. 
 Disease, insect carriers of, 24. 
 Dobson, 116. 
 Dog-day fly, 94. 
 Dogfish, 188. 
 Dogs, 277. 
 Dolphins, 264. 
 Dinosau'ria, 225. 
 Downy woodpeckers, 247. 
 Dragon flies, 118. 
 
INDEX AND GLOSSARY 
 
 359 
 
 Drone fly, 48. 
 Drones, 52, 55. 
 Duck bill, 261. 
 Duck mole, 261, 262. 
 
 Eagles, 248, 249, 252, 257. 
 Ear, 199, 307, 308. 
 Earthworms, 152-154. 
 Echid'na, 262, 263. 
 Echinoidae, 165. 
 
 Echinoder'mata ( Gr. echinos, 
 hedgehog, and derma, skin), 
 25, 161-167. 
 Economic zoology, 12. 
 Ec'toderm (Gr. ectos, outside, and 
 
 derma, skin), 168. 
 Ectopisteus migratorius, 338. 
 Edenta'ta, 27. 
 Eel, electric, 312. 
 
 lamprey, 185. 
 
 mud, 204. 
 Eggs, 293-296. 
 
 of amblystoma, 203. 
 
 of birds, 234. 
 
 of Lepidoptera, 90. 
 
 of moth, 297. 
 Egret, 255. 
 
 ElaVmobran'chii, 185, 187-189. 
 Elater'idse, 113. 
 Electric eel, 312. 
 Electric fish, 189. 
 Elephant, 268, 269, 272. 
 Elk, 267, 269. 
 
 El'ytra, pleural of el'ytron. 
 El'ytron (Gr. elytron, case), the 
 thickened anterior wings of 
 beetles and some other insects. 
 Em'bryo, 294, 303. 
 Encysted, 182. 
 
 Ephemer'ida(Gr. ephemeras, last- 
 ing a day), 26, 117. 
 En'doderm, 168. 
 English sparrow, 237, 294. 
 EntomSs'traca, 299. 
 
 Equipment, 14. 
 
 Evolution of animals, 342-354. 
 
 Eye of cat, 288. 
 
 fish, 198. 
 
 insects, 120. 
 
 locust, 34. 
 Eyes, 308, 310. 
 
 Fall web worm, 64. 
 
 Families, 28. 
 
 Feeling in animals, 303-306. 
 
 Fel'idae, 276. 
 
 Fertilization, 172. 
 
 Fiddler crabs, 137. 
 
 Fig culture, 24. 
 
 insect, 61. 
 Filaria, 325. 
 Finches, 236. 
 Firefly, 112. 
 Fish, 185-199. 
 Fish, characteristics of, 196. 
 
 hearing in, 307. 
 
 lice, 333. 
 
 products, value of, 341. 
 Fission, 179. 
 Flatfish, 194. 
 
 Flatworms, 157-161, 326, 327. 
 Fleas, 61, 329. 
 Flicker, 246, 250. 
 Flies, 24, 39-51. 
 Flounders, 194, 195. 
 Flycatchers, 230-232. 
 Flying fish, 192. 
 Flying foxes, 273. 
 Food of nestling birds, 24. 
 Forest tent caterpillar, 78, 81. 
 Forest snail, 148 
 Forests, insects affecting, 24. 
 For m&l'de hyde, 18. 
 Formaline, 18. 
 
 Forelimbs of vertebrates, 354. 
 Fossil animals, 225, 345-350. 
 
 birds, 227. 
 mammals, 265- 
 
360 
 
 INDEX AND GLOSSARY 
 
 Foxes, 276, 277. 
 Fresh water clams, 143. 
 Frog, development of, 301. 
 
 structure of, 209-211. 
 Frogs, 204-206. 
 Frogs' eggs, 294-296. 
 
 Galley worm, 133. 
 
 Gall flies, 59-63. 
 
 Gallinse, 253. 
 
 Gang'lion, a group of nerve cells, 
 
 123. 
 
 Garden spider, 129. 
 Garter snakes, 214, 293. 
 Gem'mules (L. gemma, bud), 176. 
 GSn'era, plural of genus. 
 Genus, 28. 
 Ge o ineV ri dae (Gr. ge, earth, and 
 
 metron, measure), 85. 
 Gibbons, 281. 
 Gila monster, 213. 
 Gill arches, the three or four 
 
 bony arches on either side of 
 
 the pharynx of fishes bearing 
 
 the gill tufts, 198. 
 Gills, organs of respiration used 
 
 by most aquatic animals, 162, 
 
 189, 204, 302. 
 Gland, a structure for secreting a 
 
 useful substance, 78. 
 Glass snake, 212. 
 Globigerina, 183. 
 Glow worm, 113. 
 Golden robin, 236. 
 Goose barnacles, 140. 
 Gordius, 156. 
 Gorilla, 281. 
 Grackles, 236. 
 
 Grain, insects injurious to, 23. 
 Grain weevil, 108. 
 Grape-vine louse, 97. 
 Grandady -long-legs, 130. 
 Grantia, 175. 
 Grasshopper, anatomy of, 123. 
 
 Grasshoppers, 30, 31. 
 
 sounds of, 37. 
 Grass spider, 126. 
 Great horned owl, 262. 
 
 auk, 335. 
 Green frog, 205. 
 Green turtle, 224. 
 Ground hog, 270. 273. 
 Gymnophiona, 207. 
 Gypsy moth, 80, 126. 
 
 Hairy woodpecker, 247. 
 
 Halibut, 194. 
 
 Hares, 271. 
 
 Harlequin bug, 106. 
 
 Harvest flies, 93. 
 
 Harvestmen, 130. 
 
 Hawk moths, 73, 74. 
 
 Hawkbill turtle, 224. 
 
 Hawks, 12, 248, 249, 253, 254, 
 
 255, 256. 
 Hearing, 307. 
 Heart of Amphibian, 210. 
 
 of crayfish, 136. 
 
 of mammal, 287. 
 
 of reptile, 226. 
 Hedgehogs, 276. 
 Heel fly, 49. 
 Helix, 149. 
 Hellbender, 203. 
 Hellgramite, 116. 
 Heloderma, 213. 
 He mlp' te ra (Gr. Aemi, half, and 
 
 pteron, wing), 26, 91-107. 
 Hen hawk, 251. 
 Hermit crab, 173, 138. 
 Herons, 254, 255. 
 Herrings, 190. 
 Hessian fly, 50, 125. 
 Hgterop'tera, 104. 
 Hibernation, passing the winter 
 
 in a dormant condition, 31. 
 High-holer, 246, 250. 
 Hippocampus, 193. 
 
INDEX AND GLOSSARY 
 
 361 
 
 Hirudo, 161. 
 
 Holothuroi'dea, 166. 
 
 Honey bee, 52-54, 121, 298. 
 
 Honey dew, 57. 
 
 Hop louse, 24, 97. 
 
 Hornet, 56. 
 
 Horn tail, 331. 
 
 Horse hair worms, 156, 167. 
 
 Horse bot, 330. 
 
 Horse, limb of, 353. 
 skeleton of, 266. 
 
 Horses, 266, 266, 347-350. 
 
 Host, 323. 
 
 House flies, 24, 45. 
 
 Humming birds, 244, 249. 
 
 Hydra, 168-170, 344. 
 
 Hydroids, 170, 171, 172. 
 
 Hyla, 205, 206. 
 
 Hymenop'tera (Gr. hymen, mem- 
 brane, andpteron, wing), 27, 
 62-68. 
 
 Ichneumon flies, 63-67, 331. 
 Ima'go, the adult form of an in- 
 sect, 73, 91. 
 Infusoria, 178-180. 
 Injurious insects, 12, 23-24, 34, 
 
 48-50, 124, 125. 
 Instinct in animals, 55. 
 Insec'ta (L. in, in, and seco, cut), 
 
 26, 30-126. 
 Insecticide, a substance used in 
 
 killing insects, 23, 114. 
 Insectiv'ora, 27, 274, 275. 
 Insects, 30-126. 
 feeling in, 303. 
 hearing in, 308. 
 injurious, 12, 23, 24, 34, 48- 
 
 50, 124, 125. 
 parasitic, 329-333. 
 preservation of, 16. 
 smell in, 307. 
 structure of, 121, 128. 
 taste in, 306. 
 
 lo, 311. 
 
 Itch mite, 131, 328. 
 
 Jaguar, 276. 
 
 Jar fly, 94. 
 
 Jays, 235. 
 
 Javelin bat, 274. 
 
 Jellyfish, 173, 174, 296. 
 
 Jigger, 131. 
 
 June beetle, 110. 
 
 Kallima butterfly, 313, 314. 
 Katydid, 31, 315. 
 Kangaroos, 262, 263. 
 Killing of animals, 18, 114. 
 Kingbird, 230, 232. 
 Kissing bug, 105. 
 
 Labium, lower lip, 32, 42. 
 Labrum, upper lip, 32, 42. 
 Ladybird beetles, 101, 102, 114. 
 Lamellicorn beetles, 110. 
 Lamprey eel, 187-188. 
 Larva, the first active young stage 
 
 of many animals, 39, 90, 207, 
 
 208, 298, 301, 302. 
 Leaf rollers, 86. 
 Leaf butterfly, 313, 314. 
 Leaf-eating beetles, 115. 
 Leeches, 150-162. 
 Lemurs, 280. 
 Leopard frog, 206. 
 Lepidop'tera (Gr. lepis, scale, and 
 
 pteron, wing), 26, 68-91. 
 Lepidosiren, 195. 
 Lepomis, 193. 
 Leporidse, 271. 
 Lernea, 333. 
 Leucoselenia, 175. 
 Lice, 24, 67, 95-98, 328, 329. 
 Lightning bug, 112. 
 Limax, 149. 
 Liver fluke, 326. 
 Linnaeus, 28. 
 Lion, 276. 
 
362 
 
 INDEX AND GLOSSARY 
 
 Lion, mountain, 276. 
 Lizards, 211-213. 
 
 egg of, 293. 
 Lobster, 136, 341. 
 Locust, anatomy of, 32-34, 123. 
 
 borer, 111. 
 
 Carolina, 36. 
 
 red-legged, 35. 
 
 Rocky Mountain, 12, 35. 
 Loggerhead turtle, 224. 
 Long-eared owl, 253, 258. 
 Longicorn beetles, 111. 
 Lucanus, 111. 
 Lumbricus, 152. 
 Lung fishes, 194. 
 Lungs of salamanders, 201. 
 Lynx, 275, 276. 
 
 Mackerel, 192, 193. 
 Madrepor'ic, 162. 
 Maggot, 47, 122. 
 Magpie, 235. 
 Malacostraca, 299. 
 Malarial parasite, 183. 
 Malaria mosquito, 41, 42. 
 Mamma/lia (L. mamma, breast), 
 
 27, 261-292. 
 
 Mammal, structure of, 283-292. 
 Mammoth, 335, 336. 
 Man, age of, 335. 
 Manatee, 264. 
 Mandibles, 32. 
 Man-eater, 188, 277. 
 Mantle, 145. 
 Maple borer, 89. 
 
 gall, 61. 
 
 louse, 97. 
 
 scale, 103. 
 Marmoset, 280. 
 Marmots, 270, 273. 
 Marsu'pia'lia (L. marsupium, a 
 
 pouch), 27, 263, 264. 
 Marten, 278. 
 Mastodon, 351. 
 
 Maxillae, 32. 
 
 May flies, 117. 
 
 Meadow lark, 24, 236. 
 
 Mealy bug, 103. 
 
 Measuring worms, 85, 315. 
 
 Medicinal leech, 151. 
 
 Medu'sje, 172. 
 
 Mgso hip'pus, 348. 
 
 Metamor'phosis (Gr. meta, over, 
 and morphe, form) the change 
 from one stage to another in 
 the development of the young, 
 61, 90, 91, 93, 121, 295-302. 
 
 Mice, 270, 271. 
 
 Microscope, a convex lens or a 
 combination of several such 
 lenses for magnifying objects, 
 21. 
 
 Migration of birds, 24, 260. 
 
 Milk snake, 214, 216. 
 
 Milkweed butterfly, 69. 
 
 Millipeds, 132. 
 
 Mim'icry, 214, 321. 
 
 Mink, 278. 
 
 Mite, 131, 327. 
 
 Moa, 335. 
 
 Moc'casin, 214, 219. 
 
 Mole, 275. 
 
 Molting, shedding the outer skin 
 or feathers, 215, 221. 
 
 Molting of crustaceans, 137. 
 of insects, 31. 
 
 Mollus'ca, 26, 142-150. 
 
 Molluscoi'da, aquatic worms 
 which, to the casual observer, 
 appear like plants, 25. 
 
 Monarch butterfly, 69. 
 
 Monkeys, 280 283. 
 
 Monotremata, 27, 261-263. 
 
 Moose, 267, 269, 330. 
 
 Mosquitoes, 24, 39-45.- 
 
 Moth, eggs of, 297. 
 
 Moths, 68, 73-91. 
 
 Mounting of animals, 18- 
 
INDEX AND GLOSSARY 
 
 363 
 
 Mourning cloak, 70. 
 Mouth parts of insect, 32. 
 
 of mosquito, 46. 
 Mud eel, 204. 
 Mud fish, 196. 
 Mud puppy, 203. 
 Mud wasps, 55. 
 Mur'idae, 270. 
 Mus, 271. 
 Museum pest, 114. 
 Muscles, 283-285. 
 Mussel, 143, 144. 
 Muskrat, 270. 
 Mya, 142. 
 
 Myri&p'oda (Gr. myroi, ten 
 thousand, and poda, feet), 26, 
 132. 
 
 Mysis, 299. 
 Mytilaspis, 102. 
 
 Nares, 210. 
 Natural History, 11. 
 
 selection, 322, 347-350. 
 Nau'plius, one of the larval forms 
 of crustaceans, 299, 300, 333. 
 Nautilus, 150. 
 Necturus, 203. 
 
 Nem' a thel mm' thes (Gr. nema, 
 thread, and helminth, worm), 
 25, 155-157. 
 Ngrn'atocyst, 168. 
 Nemertini, 161. 
 Nephrid'ia, organs of excretion 
 
 in the lower animals, 154. 
 Nerves, termination of, 305, 308. 
 Nervous system of bee, 121. 
 
 of cat, 289. 
 
 of crayfish, 134. 
 
 of fish, 197, 198. 
 
 of frog, 209, 211. 
 NeurSp'tera, 26, 116. 
 Newt, 199, 200 
 Night walker, 152. 
 Noctuidse, 82. 
 
 Nomenclature, 28. 
 
 Notochord, 186, 187. 
 
 Nuthatches, 241, 245. 
 
 Nut weevil, 107. 
 
 Nymph, the young form of insects 
 which do not have a complete 
 metamorphosis, 31, 36, 298. 
 
 Oak galls, 60, 67. 
 
 Oak-leaf rollers, 87. 
 
 Ocelli, simple eyes of insects, 34. 
 
 Odonata, 26, 118. 
 
 Opalina, 327. 
 
 Operculum, 189. 
 
 Ophidia, 213, 221. 
 
 Ophion, 66. 
 
 Ophisau'rus, 212. 
 
 Ophiuroi'dea, 166. 
 
 Opossum, 263, 264. 
 
 Orang-outang, 282. 
 
 Orchard, birds affecting, 24. 
 
 Order, the several groups of an- 
 imals composing a class or 
 subclass, 26. 
 
 Organism, an individual plant or 
 animal, 11. 
 
 Origin of species, 342-354. 
 
 Orioles, 235. 
 
 Or'nithorhyn'chus, the duck mole, 
 262. 
 
 Orthop'tera (Gr. orthos, straight, 
 and pteron, wing), 26, 30-38. 
 
 Ovip'arous, producing eggs, 213 
 
 Ovipositor (L. ovum, egg, and 
 positum, placed), a projection 
 from the end of the abdomen 
 of insects used in egg-laying, 
 33, 57, 94. 
 
 Owls, 12, 32, 248, 252, 253, 258. 
 
 Owlet moths, 82. 84. 
 
 Ox bot, 24, 49, 330. 
 
 Oyster, 143. 
 crab, 13&. 
 
 Oyster-shell scale, 102. 
 
364 
 
 INDEX AND GLOSSARY 
 
 Painted terrapin, 223. 
 Partridge, 254. 
 PSr a mce' cium, 178. 
 Parasites, organisms feeding on 
 living tissues, whether plant 
 or animal, 
 
 of fish, 332, 333. 
 
 of honey bee, 51. 
 
 of insects, 330-332. 
 
 of man, 131, 155, 158-160. 
 Parasitism, 323-334. 
 Par'thenogen'esis, the production 
 of young from eggs not fer- 
 tilized, as in some cases 
 among plant lice, ants, bees, 
 and wasps, 54, 95, 96, 161. 
 Passeres, 231. 
 
 Peach tree borer, 24, 89, 90. 
 Pea louse, 97. 
 Pearl oysters, 144. 
 Pearly nautilus, 150. 
 Pear slug, 24. 
 Peas, insects affecting, 24. 
 Pea weevil, 108. 
 Perching birds, 231. 
 Peritoneum, 198, 210, 286. 
 Pernicious scale, 98. 
 Petrel, fulmar, 334. 
 Petromyzon, 180. 
 Pewee, 232. 
 Phoebe, 232. 
 Phorodon, 97. 
 Photinus, 112. 
 
 Phyla, same as subkingdom, 28. 
 Phylloxera, 97. 
 Physiology, 11. 
 Pieris, 71. 
 Pigeon hawk, 264. 
 Pigeon, wild, 338. 
 Pill bugs, 140. 
 Pilot, 218, 219. 
 Pimpla inquisitor, 64. 
 Pine-bark beetle, 110. 
 Pine tree borer, 112. 
 
 Pinnipg'dia, 279. 
 
 Pisces, 27. 
 
 Puma, 276. 
 
 Planaria, 160. 
 
 Plantigrade, 266. 
 
 Plant lice, 95-98. 
 
 Plastron, 223. 
 
 Plat' yhelmin' thes (Gr. platys, 
 flat, and helmins, worm), 25, 
 157-161. 
 
 Plethodon, 201. 
 
 Pleura, 286. 
 
 Pleuronec'tes, 194. 
 
 Plum curcu'lio, 107. 
 
 Poisonous lizard, 218. 
 snakes, 313. 
 
 Polar bear, 278. 
 
 Pollina'tion by insects, 54, 62. 
 
 Pol'yp, a fixed individual animal 
 of the Coelenterata, 170. 
 
 Polyphemus, 75. 
 
 Pond snail, 147, 148. 
 
 Porlf'era, 25, 167, 176-177. 
 
 Porpoises, 264. 
 
 Potassium cyanide, 19. 
 
 Potato beetle, 115. 
 
 Prairie dog, 270. 
 
 Preservation of material, 15. 
 
 PrTmates (L. primum, first), 28, 
 280-283. 
 
 Proglot'tides, 159. 
 
 Proinethea, 76, 297. 
 
 Protective coloration, 313-823. 
 
 Proteus, 203. 
 
 Pro'tochorda'ta, 27. 
 
 PrO'toplasm, the semi-liquid ma- 
 terial forming the greater 
 part of the cells, 179, 180. 
 
 PrOtozo'a (Gr. protos, first, and 
 zoon, animal), 25, 178-184. 
 
 Pseu'dopods (Gr. pseudeo, false, 
 and poda, feet), 182. 
 
 Ptarmigan, 319, 320. 
 
 Pulex, 329. 
 
INDEX AND GLOSSARY 
 
 365 
 
 Pupa, the last stage in the develop- 
 ment of an insect before as- 
 suming the adult form, 40, 91, 
 298. 
 
 Pupate, to transform into the 
 state of a pupa, 74. 
 
 Python, 219, 220, 352. 
 
 Quahog, 142. 
 
 Quail, incorrect name for bob- 
 white, 318. 
 Queen, 52, 55, 66. 
 
 Rabbits, 214, 216, 334, 836. 
 
 Racer, 214, 216. 
 
 Rain worms, *52. 
 
 Raja, 189. 
 
 Rana, 205. 
 
 Raptores, 248. 
 
 Rats, 270, 271. 
 
 Rattlesnake, 217, 318. 
 
 Rays, 187, 189. 
 
 Red-backed salamander, 201. 
 
 Red bat, 278. 
 
 Red-tailed hawk, 251, 256. 
 
 Reed bird, 235. 
 
 Regeneration, the renewal of a 
 
 lost part, 154. 
 Reindeer, 23, 267. 
 Reproduction in animals, 844. 
 Reptilia, 27, 211-226. 
 Rhizop'oda (Gr. rhiz, root, and 
 
 poda, feet), 180. 
 Rice bird, 235. 
 Roaches, 88. 
 
 Robin, 242, 246, 247, 258, 259. 
 Rocky mountain goat, 266, 267. 
 
 locust, 12, 85, 259. 
 Rodentia (L. rodens, gnawing), 28, 
 
 269. 
 
 Rose aphids, 96. 
 
 Rose-breasted grosbeak, 236, 237. 
 Rose, insects affecting, 59. 
 Rose scale, 103. 
 
 RO'tifers, microscopic worms of ten 
 present in stagnant water, 161 . 
 
 Round worms, 155, 157, 325. 
 
 Rudimentary structures, those 
 which by evolution have be- 
 come too small, to be of use as 
 the toe on either side of the 
 foot of a cow or pig, 352. 
 
 Ru'minants, hoofed animals which 
 chew the cud, 268, 853. 
 
 Sacculi'na, 332. 
 Salamanders, 200-204. 
 Salmon, 191, 340. 
 Salvelinus, 192. 
 Sand dollars, 166. 
 Sand wasps, 55, 
 Sanina, 89. 
 
 San Jose scale, 24, 98-102. 
 Saw fishes, 189. 
 Sawflies, 57-59. 
 
 Scale insects, sucking insects 
 which excrete material form- 
 ing a covering for the body, 
 23, 24, 98-104. 
 Sceleporus, 212. 
 Scolopendra, 133. 
 Scomber, 192, 193. 
 Scorpion, 132. 
 Screech owl, 253, 258. 
 Scurfy scale, 103. 
 Sea anem'one, 174, 806. 
 
 cow, 264, 335. 
 
 cucumber, 166. 
 
 horse, 193. 
 
 lily, 167. 
 
 lion, 279, 280, 887. 
 Seal, 280, 337. 
 Sea urchin, 164-166. 
 Senses of animal, 303-810. 
 Serous membranes, 286. 
 Sertularia, 172. 
 Sesia acerni, 89. 
 Sesiidse, 89. 
 
366 
 
 INDEX AND GLOSSARY 
 
 Seventeen-year cicada, 92, 298. 
 locust, 92, 298. 
 
 Shad, 191, 334. 
 
 Shade trees, insects enemies of, 
 23, 79, 83. 
 
 Sharks, 187-189. 
 
 Sharp-shinned hawk, 251, 254. 
 
 Sheep tick, 51. 
 
 Shellfish, 142-147. 
 
 Ship worm, 144. 
 
 Shrew, 274, 275. 
 
 Shrimp, 141, 300. 
 
 Silk worm culture, 23. 
 
 Silk worms, 75-78. 
 
 Silver-fish, 24. 
 
 Silver-spotted fritillary, 70. 
 
 Siren, 204. 
 
 Siren'ia, 28, 264. 
 
 Skate, 189. 
 
 Skeleton of cat, 290. 
 horse, 266. 
 
 Skinks, 212. 
 
 Slipper animalcules, 178. 
 
 Sloths, 264. 
 
 Slug, 148. 
 rose, 59. 
 pear, 59. 
 
 Smell, 306, 307. 
 
 Snail, 147, 148. 
 
 Snake embryo, 303. 
 
 Snakes, 213-221. 
 
 Snapping turtle, 223. 
 
 Snout beetles, 107. 
 
 Snowy owl, 321. 
 
 So'mites (Gr. soma, body), 33. 
 
 Song sparrow, 239, 240. 
 
 Sow bug, 140. 
 
 Sparrow hawk, 251, 255. 
 
 Sparrows, 236-240. 
 
 Species, 28. 
 
 Sperm, the male cell which, unit- 
 ing with the egg, fertilizes it, 
 thus rendering it capable of 
 developing into a new ani- 
 mal, 170, 172. 
 
 Spermatozo'a, plural of sperma- 
 tozoon. 
 
 Spermatozoon, same as sperm. 
 
 Sphinx moths, 73. 
 
 Spider crab, 316. 
 
 Spiders, 125-130. 
 
 Spinnerets of spiders, 129. 
 
 Spinning moths, 74. 
 
 Spiny ant eater, 263. 
 
 Splint bone, 266, 353. 
 
 Sponges, 175-177. 
 
 Spontaneous generation, the de- 
 velopment of a living body 
 from dead material, 342-344, 
 
 Spores, 182, 343. 
 
 Sporozd'a, 182. 
 
 Spring peeper, 206. 
 
 Spruce beetles, 109. 
 
 Squalis, 187. 
 
 Squamata, 211. 
 
 Squash bug, 24, 105. 
 
 Squid, 149. 
 
 Squirrels, 270. 
 
 Stable fly, 46. 
 
 Stag beetle, 111. 
 
 Starfish, 161, 165. 
 
 Stegomy'ia, 41. 
 
 Sternum, 33. 
 
 Stinging insects, 51-56. 
 
 Strawberry weevil, 24, 109. 
 
 Strongylus, 325. 
 
 Struggle for existence, 334. 
 
 Subkingdoms, 25-28. 
 
 Suckers, 190. 
 
 Sunfishes, 193. 
 
 Survival of the fittest, 334. 
 
 Swallows, 240. 
 
 Swallowtails, 71. 
 
 Swifts, 244, 249, 250. 
 
 Symbio'sis, 323. 
 
 Syrphus flies, 48. 
 
 Tach'ina flies, 47, 332. 
 Tadpole, 207, 208, 301, 302. 
 Taenia, 158, 327. 
 
INDEX AiND GLOSSARY 
 
 367 
 
 Talons, 249. 
 
 Tape worms, 158, 326, 327. 
 
 Tarantulas, 126. 
 
 Taste, 305. 
 
 Teleos'tomi, 185, 189-199. 
 
 Tendon, 284. 
 
 Tent caterpillar, 78-82. 
 
 Terguin, 33. 
 
 Terrapin, 223. 
 
 Terrestrial, living on land. 
 
 Thales'sa, 66, 331. 
 
 Thainno'phis, 214. 
 
 Thorax, 32. 
 
 Threadworms, 155-157. 
 
 Thrushes, 242, 243, 247. 
 
 Tick, 51, 327, 328. 
 
 Tiger, 276. 
 
 Tin'ea, 88, 89. 
 
 Tine'idse, 88. 
 
 Tine'ola, 88. 
 
 Titmouse, 242. 
 
 Toad, 23, 206, 267. 
 
 eggs, 294, 295. 
 
 Tobacco, insects affecting, 23. 
 Tomato-worm moth, 74. 
 Torpedo, 189. 
 Tortoises, 222, 223. 
 Tortricidae, 86. 
 Tra'chea, 34. 
 Trapdoor spider, 128. 
 Tree frog, 205, 206, 316. 
 Trichina, 155, 156, 325. 
 Troch el min' thes (Gr. trochos, 
 wheel, and helmins. worm), 
 aquatic worms, 25. 
 Trout, 192. 
 Tulip tree scale, 103. 
 Turtle, egg of, 293. 
 Turtles, 222, 224. 
 Tussock moths, 79, 83. 
 Tympanic membrane, 397, 308. 
 
 Umbo, 145. 
 
 Ungula'ta (L. unguis, nail), mam- 
 mals bearing hoofs, 28, 265. 
 
 Unio, 143. 
 Urchins, 165. 
 Urodela, 200-204. 
 Ur'sidse, 279. 
 
 Vampire bats, 274. 
 Vanessa, 71. 
 Variation, 347-352. 
 
 in color, 278, 279, 320-323. 
 Veliger, 299. 
 
 Venomous, poisonous, 216, 218. 
 Ventricle, the cavity of the heart 
 
 sending forth blood, 289. 
 Venus, 142. 
 
 Vermes, worms, 150, 161. 
 Vermiform appendix, 353. 
 Vertebrata, 27, 185-292. 
 Vesper sparrow, 239. 
 Vinegar eel, 155. 
 Vireo, 242, 243, 258. 
 Vivip'arous, giving birth to young 
 
 instead of laying eggs. 
 Vocal cords, 287. 
 Vorticel'la, 180. 
 Vulpes, 277. 
 Vulture, 249. 
 
 Walking stick, 37, 314. 
 
 Walruses, 279. 
 
 Warble-fly, 330. 
 
 Warblers, 258. 
 
 Wasps, 55, 59. 
 
 Water boatman, 106. 
 
 Water fleas, 138, 139. 
 
 Water moccasin, 214. 
 
 Water snake, 215. 
 
 Weasel, 277, 278, 322. 
 
 Weevils, 23, 24, 107. 
 
 Whales, 264, 352. 
 
 Wheat, insects affecting, 23, 50, 
 
 57. 
 
 midge, 51. 
 
 Whip-poor-will, 245, 318. 
 Wildcat, 275, 276. 
 
868 
 
 INDEX AND GLOSSARY 
 
 Wild pigeon, 338. 
 Wire worms, 118. 
 Witch-hazel galls, 61. 
 Wolves, 277 
 
 Woodchuck, 270, 273, 337. 
 Woodcock, 317. 
 Wood lice, 141. 
 Woodpecker, 245, 259, 293. 
 Wood thrush, 243, 247. 
 Wood tortoise, 222. 
 Workers, 52, 56. 
 Worms, 25, 26, 150-161. 
 
 parasitic, 324. 
 Wrens, 240, 241, 246. 
 
 Yearbooks of Department of Ag- 
 riculture, 23. 
 
 Yellow fever mosquito, 41. 
 Yellowjacket, 55. 
 Young, development of, 294-303. 
 
 Zoaea, 299. 
 
 Zoology, 11. 
 economic, 12. 
 
 Zo'ophytes (Gr. zoon, animal, 
 and phyton, plant), plantlike 
 animals, such as hydroids, 
 172. 
 
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