NRLF B 3 272 ODt, HORACE GUNTKORF Scientific Literature San Wego, California yLA&{ z? THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID FIELD ZOOLOGY CRARY A TEXT-BOOK OF FIELD ZOOLOGY INSECTS AND THEIR NEAR RELATIVES AND BIRDS BY L. E. CRARY ASSISTANT PROFESSOR OF BIOLOGY AND GEOLOGY, KANSAS STATE NORMAL COLLEGE, EMPORIA. WITH ONE HUNDRED AND SEVENTEEN ILLUSTRATIONS PHILADELPHIA P. BLAKISTON'S SON & CO. 1012 WALNUT STREET 1911 COPYRIGHT, 1910, BY P. BLAKISTON'S SON & Co. Printed by The Maple Press, York, Pa. AUTHOR'S PREFACE. This book is intended primarily for students who have had little previous knowledge of insects, or animals of any sort. The animals chosen for discussion have been the more familiar ones which live with us from day to day. Two modes of approach to the subjects of study are in- tended : the investigative study of the animals themselves, as provided for in the directions for field work with the different groups of animals ; and the class discussions of the facts observed, in their bearing upon each other and upon the many problems which living beings are continually offering for our solution. In the latter phase of study the teacher must be a large factor. One cannot put into a text-book all there is in a subject The present form of the book is the outcome of its progressive use in the school-room, and thus has, at least, the merit of having been tried. The method of presentation of the subject is based upon two lines of belief : first, that life is one of the most interesting facts of creation, if not the most interesting; and, second, that life is a continuous fact, of common powers but various in its expression, whether one proceeds from the simple to the complex, from the early to the late, or from the low to the high. These are facts that are usually reserved for the student who has already acquired some body of knowledge of animal life; but younger stu- dents, beginners, find quite as much delight and profit M347653 vi AUTHOR'S PREFACE. in the discovery of their own similarities to forms of life unlike themselves, and in the fact that life powers are not theirs by right to the exclusion of other animals, which may even transcend them in some of these powers. The writer stands indebted to several authors whose work has covered a much larger field, notably Comstock, Folsom, Galloway, and Kellogg, and the many excellent workers in the Government Biological Survey and the Bureau of Entomology. Courteous permission was given to use various illustrations, by Henry Holt & Co., by Doubleday, Page & Co., of New York, and by James T. Hathaway, of New Haven, Conn. TABLE OF CONTENTS. PART I. INSECTS. CHAPTER PAGE I. Introduction to insects . . . . ... .. .- i II. Special senses of insects ........ 7 III. Vital processes of insects. ....... 20 IV. Development and metamorphosis .. ..... . 32 V. Insects and their classification ...... 42 VI. General suggestions for field work on insects. . .... . . . .. , . . . . ., . . 46 VII. Field work on Coleoptera ...:... 59 Coleoptera 67 VIII. Field work on orthoptera ., . . 79 Orthoptera , ...... . ..... ,, . . 87 IX. Field work on hemiptera . 98 Hemiptera . . . ... ..... . . . . 107 X. Field work on lepidoptera . . . . . . . 119 Lepidoptera . . . . . . . . , . . . . 125 XI. Field work on hymenoptera ... . . . 139 Hymenoptera ... ... . ....... 149 XII. Field work on diptera . . . ... . . . 176 Diptera . . . . . , .. . . . . . ... 183 XIIL Odonata . . . . . . . ... . .. . . 207 XIV. Ephemerida 213 XV. Plecoptera .............. 217 XVI. Neuroptera ....... . . . . . . 221 XVII. Siphonaptera ... . .5.. ..;... 226 vii Vlll TABLE OF CONTENTS. PART II. ARTHROPODA EXCLUSIVE OF INSECTS AND CRUSTACEANS. CHAPTER PAGE XVIII. Near relatives of insects . . . . . . . .'231 XIX. Key to families of spiders . . . . . . . 246 PART III. BIRDS. XX. General suggestions for field work on birds 249 XXI. Introduction to birds 252 XXII. Physical features of birds . . . ... . 262 XXIII. Migrations and nesting habits . \- .,. . 274 XXIV. Food of nestling birds . . .... . . . . 287 XXV. Nervous system and special functions . . 296 XXVI. Passeres .... 307 XXVII. Picariae . V'.Y. . . . . . '*. . . .- . 312 XXVIII. Psittaci . .... . . . . . . . -/. 316 XXIX. Raptores , 318 XXX. Columbae . . . . . . . . . . . . . . 320 XXXL Gallinae . . .' , . . '. . . . . . . . . 322 XXXIL Limicolae. . . . . .. '. ". '"'; '. , . . ; .. . . 327 XXXIII. Herodiones. . ...;...!.. \ .', 331 XXXIV. Alectorides . . . ,"/ . ^ . . , , .\ . 334 XXXV. Lamellirostres . . . . .... . . . . 337 XXXVL Steganopodes. . } . . . . . . . ... 343 XXXVII. Longipennes 347 XXXVIII. Pygopodes . .. . ....... . '. : . 350 INDEX . .... . . ": . . . " . , . . . 357 LIST OF ILLUSTRATIONS. 1. Skull of a grasshopper . 4 2. Portion of compound eye of a fly ....... 8 3. Median ocellus of a honey bee . 9 4. Antenna of a carrion beetle . . . . 12 5. Tactile hair 14 6. Nerve endings in tip of labial palpus of a fish moth . 1 6 7. Ear of a grasshopper . . . . . ; . . . . . . . 17 8. Locust from lateral aspect, auditory organ ... 18 9. Auditory hairs of a mosquito ......... 18 10. Antenna of a mosquito . * . . . . ... . . 19 1 1 . Tracheal system of an insect . . ... . . . . . 21 12. Tracheal gill of a Mayfly ......-. 22 13. Digestive system of a beetle .......... 25 14. Stages in development of nervous system of a dipter water beetle . .' . . .... 29 15. Concentration in nervous system of a dipter . . 30 1 6. Hypermetamorphosis of Epicauta cinerea . . ... . 34 17. Larva of tomato worm .... . ....... 35 18. Pupa of tomato worm .... . ' . ' : . '. .-. . . 36 19. Adult of tomato worm ..,'...-,..... 37 20. Development of squash bug .......... 41 21. Diagram of insect net 1 .... 49 22. Dip net ..................... 50 23. Drying board 55 24. Great water scavenger ..'... 61 25. Egg case of water scavenger . . . . _ . . . . 61 26. Larva of water scavenger 62 27. A flower beetle, Euphoria inda 62 28. Some California ladybird beetles 70 29. The searcher 71 ix [ LIST OF ILLUSTRATIONS. FIG. PAGE 30. Ventral aspect of a carabid beetle 72 31. Various forms of antennae 75 32. Legs and tarsi of beetles . . .' . . . . .... 76 33. Metamorphosis of a beetle, Cyllene pictus .... 77 34. Hypermetamorphosis of Epicauta cinerea .... 78 35. Locust with external parts named 88 36. Short-horned grasshopper 89 37. Long-horned grasshopper 90 38. Cricket-like grasshopper. . . 91 39. Croton bug - 93 40. Oriental cockroach 93 41. Native cockroach 94 42. Praying mantis 95 43. Dapheromera femorata 96 44. Giant waterbug 100 45. Development of a cicada 103 46. Front wing of an hemipter .......... 107 47. Mouth parts of an hemipteron . . . . . . . . . 108 48. Short-winged chinch bug . . . . . . . . , . . 113 49. Soldier bug , . . . . . . . . . . 117 50. Assassin bug . .... . . ...... .... 117 51. Lepidopter wing to show scales . . ..... . 125 52. A, front wing of monarch butterfly to show venation "...........126 B, hind wing of monarch butterfly to show venation . . .... . . ... 126 53. Head of a butterfly . . . .... . . . . . . . 127 54. Adult of tomato worm . . . ; 128 55. Sphinx moth at petunia flower 128 56. Wing of moth to show jugum ' . . 129 57. A, wing of moth to show' frenulum ....... 130 B, wing of butterfly to show frenulum substitute. 130 58. Artificial ant nest : .... 143 59. Thalessa linator ............... 151 60. Pigeon horntail . ^ ... 152 LIST OF ILLUSTRATIONS. XI FIG. PAGE 61. Mouth parts of a honeybee . , . ... . . . 153 62. Tongue of a honey bee . . . . ........ . . . 153 63. Head and mouth parts of a honey bee . . . . . 156 64. Honeybee, worker, etc . i& . . . ... . . . 158 65. Portion of brood comb of honey bee, one queen cell 159 66. Modifications of leg of worker honey bee ... . 162 67. Nest of mud dauber . . _. . , . ! . -. . . . . . 163 68. Honey bee showing wax scales 169 69. Cicada killer . ... . .... ..... . . . 169 70. Tarantula killer 170 71. Nest of "paper wasp . . ,- . .- . . 174 72. Blow fly 177 73. Mouth parts of a horse fly 184 74. Antennae of flies ... 185 75. Ocelli and compound eyes of a fly 186 76. Metamorphosis of an oviparous fly, Phormia regina 187 77. Stable fly . 189 78. Mouth parts of house fly . . ; .. . . . ; . . . 189 79. Foot of a house fly * 190 80. A house fly ;.. ^ . . . . ./ . . . . . 190 81. Mouth parts of a female mosquito 194 82. Life history of a mosquito . ... . i -. ... . . 195 83. Female Anopheles with antenna of male .; j . . . 197 84. Antennae of a mosquito (Culex) . . 4 . . . . . 199 85. A flower fly . .' 201 86. A bee fly . . .' . . . . . . ... . ...... 203 87. Stages in development of a dragon fly ..... 210 88. Nymph and adult of a May fly. . . . . . . . . 214 89. Nymph and adult of a stone fly . .. . . '. . . ' . 218 90. Lace-wing depositing eggs .......... 222 91. Larva of a dobson ..."...... 223 92. Adult dobson 224 93. A mantispa .,..-...;.......... 225 94. Egg, pupa, and adult dog flea ........... 228 95. A milliped ..... . .-, . . ....... 232 Xii LIST OF ILLUSTRATIONS. FIG. PAGE 96. A centiped 233 97. A scorpion 237 98. The archaeopteryx 254 99. Conirostral bill of a canary 262 100. Falcatee bill of a crossbill 262 101. Fissirostral bill of swallow ^ . . . . 263 102. Fissirostral bill of a chimney swift 263 103. Hooked and cered bill of a hawk 263 104. Tenuirostral bill of a nuthatch . . 264 105. Hind limb or leg and foot of a bird 265 1 06 Front limb or wing of a bird *. . . .-270 107. Typical passerine foot 307 108. Loggerhead shrikes 309 109. Syndactyle foot of a picarian bird 312 no. Belted kingfisher 314 in. Zygodactyle foot of a parrot 317 112 Semipalmate foot of a plover 328 113. Lobat-e foot of a coot 336 114. Wood duck . . 341 115. Totipalmate foot of a pelican 344 1 1 6. Pelican 345 117. Palmate foot of a tern 347 PART I. r " ..-;; INSECTS. I ' y "... ^ CHAPTER I. INTRODUCTION TO INSECTS. Biology. Biology, the word, is made from the two Greek nouns bios, meaning life, and logos, meaning speech, reason, word, that is, something given with authority. Hence biology discusses life in its many phases, its structural means of maintaining itself, and its power of perpetuating itself from one generation to another. Biology, then, concerns itself with both plants and animals, and we have plant biology and animal biology. Zoology. Zoology is built from the two Greek nouns zoon, meaning an animal, and logos; hence zoology is the discus- sion of animal life in its many phases of activity and power. The systematic zoologist divides the many forms of animal life into branches according to their large similarities and dissimilarities. He may, for example, establish the two classes, Protozoa one-celled, non-differentiated animals, very simple in structure; and Metazoa many-celled i 2 FIELD ZOOLOGY. animals, many of them highly differentiated. Under the second class, he may establish such branches as the Coelenterata, animals with a continuous body cavity, this cavity having but a single opening, which serves both as mouth and as anus; Echinodermata, animals of radiate structure, no backbone, and the body surface beset with spines (from e chinos, a hedgehog, and dermos, skin) ; Mollusca, including such animals as snails and clams; Arthropoda, animals with organs of locomotion jointed in successive segments, literally joint-footed (from arthron, meaning joint or articulation, and poda, meaning organs of locomotion) ; and Chordata, animals having a nervous cord, or a backbone, or both. The last-named branch includes such animals as the sea squirts with only a ner- vous cord; and the fishes, the frogs, the reptiles, the birds, and the mammals, with a vertebrate skeleton. This work confines itself to the study of portions of two of these branches the Arthropoda; and the Aves, or birds, under the Chordata. Under the branch Arthropoda are found insects, scorpions, mites and ticks, millipeds and centipeds, spiders, and the large class of the crusta- ceans. The crustaceans will be left for consideration else- where, and we shall confine our study to the insects with their near relatives, and birds. The class Insecta includes only the insects, and it is itself divided according to the similarities and dissimi- larities of the many kinds of insects. The name insect is applied to such animals as have the body cut into successive segments. These segments are for the most part grouped so as to form three general regions, the head, the thorax, and the abdomen. The whole body may be composed of distinct and similar segments, as in the caterpillar; or may be greatly modified INTRODUCTION TO INSECTS. 3 to serve some special purpose, as in the honey bee. The segments composing the head are, in most insects, so fused as to form a single box-like head-covering of one sclerite only. In the larva, the separate head sclerites are usually to be found. The three segments forming the thorax are, in many insects, so fused as to be separated with difficulty; but are observable in the generality of insects, being seen most easily on the under side of the body. Catch two or three large jumping grasshoppers, the sort that do not fly so well as they jump. Put one into the killing-bottle and let it stay there while you examine the others. Seize one of them by the abdomen carefully and you will be likely to realize the strength of the muscles of its strong hind legs. If human beings were able to kick as vigorously in proportion to their size, woe to their enemies ! There would be left neither vestige nor trace. Let the hopper try its jaws on your finger, and you will sense the efficiency of leverage in the jaw muscles. Set it on the table and measure the length of its jump. This indicates good muscle, and stiff skeleton for fasten- ing the muscles to. All grasshoppers are injurious, so no harm will be done by putting these into the killing-bottle after finishing the experiment. Now take out the other hopper from the killing bottle, and with a sharp knife sever the thorax from the abdomen ; cut off the head also, and let fresh water run through the thorax till all the soft internal parts are washed away. What is left will be chiefly muscular tissue, the complex muscular system of the thorax. Accompanying these muscles may be seen the white fibers of the nervous system, but the muscular tissue may be plainly seen, part of it consisting of strands fastened to the top sclerites of the thorax, part fastened to the sides, and part crossing to reach the first joint of the 4 FIELD ZOOLOGY. leg on either side, while still another part of the mass will be found to pass laterally to attach to the ribs of the wings. Now for the mouth parts : Give your living grass- hopper a fresh young grass leaf, and watch it through the reading-glass. On the head will be found several pairs of jointed organs with which it seizes and handles the leaf. B FIG. i. Skull of a grasshopper, Melanoplus differ entialis. a, antenna; c, clypeus; e, compound eye; /, front; g, gena; /, labrum; Ip, labial palpus; m, mandible; mp, maxillary palpus; o, ocelli; oc, occiput; pg, post-gena; v, vertex. (Folsom.) The mandibles are first used; they seize the leaf; the maxillae break up the green bits into smaller pieces ; then is seen the labium or under lip, which seems to have no further use than to turn the food bits round and round and keep them from falling out of the mouth. Besides these, at the side of the mouth opening and well in front, are two pairs of hair-like appendages which are constantly INTRODUCTION TO INSECTS. 5 in motion in and out of the food mass; these are the palpi or feelers; one pair is attached to the labium and the other pair to the maxillae. It is thought that there are developed on these palpi of the grasshopper the taste buds which give the insect its taste impressions, its sense of relish or disapproval of the food under consideration. On the front of the head, well toward the eyes, are the antennas, and these are sense organs for all insects, though not giving the same sensation in all cases. Touch the antenna of your' grasshopper very lightly, and it gives a quick jerk. Threaten without striking, and, if the insect does not jump away, the same response will be given. Make a loud noise near the insect's antennae, and the antennae will wave about as if in response. As to other insects, some use the antennae as ears, while others use thefn as noses. The true uses of the grasshopper's antennae are not known. Here is an opportunity for some- one with time and patience, to discover a valuable fact. As to the abdomen, in most adult insects the abdomi- nal segments are fairly distinct and similar, thus retaining the form of the primitive type of insect ; for in insects, as in all animals, the simplest form is the undiflerentiated or similarly-segmented type or individual. The insect's body wall is cuticle, but it is rendered firm and horny by the addition of a substance called chitin, a substance which serves for the protection of the soft internal organs, and also for the attachment of the many muscles necessary in running, flying, fighting, home- making, and other activities of insect life. There is no internal skeleton, .but the chitinized cuticle serves the purpose of an exoskeleton. From this exoskeleton, especially in the thorax, many processes of the body wall project inward for- the attachment of the muscles of the 6 FIELD ZOOLOGY. wings and the legs. The insect's body wall is rendered flexible by the fact that between any two segments there is a non-chitinized area; these chitinized areas with the non-chitinized areas between constitute sclerites, and the degree of flexibility depends upon the depth of the infold- ing of the soft, non-hardened cuticle between any two sclerites. Looking the grasshopper straight in the face, there will be seen a sclerite coming down from the upper part of the face and nearly covering the mandibles, the maxillae, and the other mouth parts. This is the labrum or upper lip; it is hardly to be called an appendage of the mouth, but is rather a fold of the cuticle covering the mouth. The mandibles usually consist, as in the grasshopper just studied, of one segment. The labium usually forms one single piece, but in many of the insects it is modified into several pieces, as in the flies, the bugs, and the butterflies. In certain insects, some of the other mouth parts may be reduced to mere rudiments or may be lost altogether, not developed because functionless. At the side of the grasshopper's head may be seen the large compound eyes. With a hand lens these will be seen to be composed of a large number of very small flat faces, instead of forming one smooth, globular surface like the human eyeball. Just inside the margin of each compound eye may be found two of the simple eyes, and lower down in a groove of the grasshopper's face is the third simple eye. These look like tiny beads. A house- fly has three of these simple eyes, but they are set in a much smaller triangle between the two compound eyes and more nearly on top of the head. CHAPTER II. SPECIAL SENSES OF INSECTS. Sight. Both simple and compound eyes are found on most insects; but some have either kind alone, and a few have no eyes at all. The most primitive living insects to-day have eyes, and the larvag of the complex insects have simple eyes. Hence, if the highest individual in any given class repeats the life history of the individuals below it, it is only fair to suppose that the possession of eyes is inherent in all insects; and, where there is a lack of eyes, it must be attributed to disease or some other environ- mental conditions bringing about non-development or disuse, and therefore degeneracy of the part not used. The compound eye is not an aggregation of simple eyes; the two sorts of eyes differ in structure, and there is good evidence that they are not derived from the same line of body differentiation. The compound eyes of insects are two in number, and are usually situated on the upper head areas, a little to one side of the middle line. They are usually conspicuous; in the dragon fly and the house fly they are large in proportion to the rest of the head. The dermestidse, the pests of the insect collector, count the head of a dragon fly a rich treat and will eat out the soft internal parts, leaving the corneal facets quite clear. Many insects, as the butterflies, the dragon flies and the house flies, have an enormous number of facets, 7 8 FIELD ZOOLOGY. in some insects numbering as high as thirty thousand. Behind each facet is an eye element which is supposed to enter the nerve tract by a separate nerve fiber. . This eye element includes a cone of crystalline clearness, with the tapering end enveloped more or less completely by pigment. Behind each cone are retinal cells, ganglionated nerve cells, and nerve fibers, all finally passing into the optic tract, or the tract of the optic nerve. Each of these eye elements is supposed to perceive only that part of the object which is directly in front of its surface. Since the nerve fibers pass separately from each eye ele- ment into the optic nerve, it is nc possible that the sensations are received separately by the optic lobes of the brain. Whether FIG. 2. Portion of compound they are put together by the eye of fly, Calliphora vomitoria, interpreting hea d ganglion to radial section, c, cornea; i, ins . . form an image as in the human If the pigment; n, nerve fibers; nc, nerve cells; r, retinal pigment; t, trachea. (Folsom, after Hick- son.) eye, is very doubtful, impressions are interpreted separately, the insect has sight in no such sense as has the human being; but the visual impression must be a composite of the image, made up of as many parts as there are corneal facets on the side of the head next to the object. Such sight is called mosaic sight. It' would follow, then, that insects whose eyes pro- ject much beyond the head contour, which possess the largest number of facets, and which, in addition, can turn the head through the greatest possible angle, must have the SPECIAL SENSES OF INSECTS. most nearly complete mosaic of the object at which they look, that is, come nearest to seeing as we ourselves see. The simple eye appears externally as a convex bead- like object, and as such is a transparent area of the head cuticle, thickened so as to protrude from the surface of the head. This makes a lens, convex on the outer side and indicating that, by means of the simple eyes, such sight as the insect has must be near- sight. Through this lens the light rays pass to a layer of specialized skin cells with pigment pres- ent . Directly back of the lens there is also a more or less developed vitreous body, its development varying with the order of insects. Fibers from the Cells of the pigment layer FIG. 3. Median ocellus of honey-bee, Apis mellifera, in sagittal section. h, hypodermis; /, lens; n, nerve; p, iris pig- ment; r, retinal cells; v, vitreous body. passing tO the Cephalic (Folsom, after Redikorzaw.) ganglion. The eye is a part of the nervous system, and the nervous system arises as a differentiation of the surface cells of the animal of primitive type. For instance, in the sponge, where the body is like a sack, the body consists of three layers, two of them in contact with the water in which the sponge lives. The outer one of these layers, the ectoderm, discharges the functions of our tactile merge into the tract of an optic nerve branch 10 FIELD ZOOLOGY. corpuscles, not to speak of functions attributed to other organs of ours, as those organs that give us the sensations of light and darkness, heat and cold, all of them differ- entiated parts of our complex nervous system. The cells of the interior layer of the body, the entoderm, perform the functions of our highly elaborated alimentary system, while the skeleton of the sponge is the product of the working energy of the middle layer of cells, the mesoderm. This general division of functions holds true for other animals from the sponge to the complex animals; the primitive ground sense, not localized, but distributed over the body surface in the simple animal, becomes the nervous system of the more complex animal and is there differentiated into touch, sight, taste, hearing, smell, temperature, and other sensations believed to be inter- preted by the reflex or the spinal system. But an organ, on its first appearance, is little differentiated from the surrounding tissue, and only gradually reaches higher levels of perfectness; hence the simple eye is probably an earlier expression of a light sensitive, chiefly useful in distinguishing light from darkness; while the compound eye may be said to represent a later and more complex organ of sight. The function of the simple eye is not certainly known. In those animals which see most definitively, that is, which come nearest to forming a perfect image, the simple eye has gone through no develop- ment from its primitive structure, while the compound eye, in these insects, has the greatest number of facets, seeming to indicate that the compound eye is the effective organ of sight. Again, as to the simple eye : wherever in any animal, simple or complex, pigment is present in the skin cells, those cells must be sensitive to light; that they are so SPECIAL SENSES OF INSECTS. II may be proved in several ways. For this reason scien- tists are disposed to regard the simple eye rather as an organ sensitive to differences in the amount of light falling upon them. This light sense is a dermal possession of many of the lower animals ; some of the minute one-celled animals living in the water respond to changes in the light intensity. The earthworm, with no eyes at all, is sensible of the fact that it has come above ground, and turns downward again. Your own skin, exposed to sun- light, responds to the action of the light without any volition of yours, and you say that you freckle or tan. Bees sometimes know their hive by the color; whether this sense plays any part in the wonderful "homing instinct" of these insects is not certain, but they use this sense in seeking food, as do many other animals, insomuch that we say bees prefer certain colors of flowers, while flies as a rule prefer other colors. It seems likely that butterflies' bright colors are useful as recognition marks to guide others of their kind. A clue as to the other possible uses of bright markings on butterflies' wings may be found in the fact that the wings of old butterflies are frayed and often have pieces torn from them, as if bird enemies had aimed for the wing spot instead of for some more vital part. Smell. Smell is a sense highly developed among insects. Among bees and ants the development of this sense seems not equalled elsewhere in the animal kingdom. Who has not at some time seen ants swarm in from some un- known place toward the sugar jar or the plate of frosted cake? It could not have been chance, for their path led through many difficulties. Honey bees have been 12 FIELD ZOOLOGY. known to find a plate of honey left on the kitchen table. A human being could hardly have smelled the honey at close range. In the case of human beings, the olfactory nerve of one person may carry stimuli for certain odors, and not be at all responsive for other odors. Again, it is difficult for a human being to discriminate between odors somewhat similar, as odors of different flowers, different teas, or different foods. Personal clean- liness generally obliterates for us any olfactory recognition mark of our own race ; and yet the approach of a member of a different race is an instant olfactory suggestion. Out of all this must come this concession : the fact that we do not perceive an odor does not prove that the olfactory sense of some other living being may not respond to it. . - The immediate smelling organs in the case of insects are exceedingly small papillae or pits, at the bottom of which a fiber from the olfactory lobe of the brain ganglion is spread under the thin body tegument. These organs are often found on the antennae. Carrion beetles have what seem to be unmistakably olfactory organs on their antennae and also on their palpi. Flesh flies, which are so often attracted considerable distances by the odor of decaying meat, lose this means of finding their food after their antennae are removed (Hauser). Many moths use this sense as a means of recognition of the other sex, and have been proved by experiment to be unable FIG. 4. Antenna of a burying beetle, Necrophorus Americanus, showing sense pits in end segments. SPECIAL SENSES OF INSECTS. 13 to find their mates when the antennae have been removed or coated. On the wings of the big red-brown monarch butterfly are pockets in which are carried scent scales. Ants are thought to be able to perceive odors in so far as to recognize members of their own colony, the path over which a nest-mate has passed or which they them- selves have recently traversed, and to know an enemy by the fact that the new ant smells different from their nest-mates. There are plenty of instances which might be cited to prove that man is really inferior to many of the lower animals in the small range of discrimination possible in his olfactory sense. The elephant, the deer, the fox, the wolf, the dog, all bear evidence to an olfactory sense wonderful in its development. Our impressions of delight, aversion; comfort, danger; friend, foe, are more often the result of mental processes. In most affairs of life we think why we should feel, rather than instinctively feel without thinking. Yet, in cases so new that no previous experience could reason out an explanation, we may act from instinctive feeling we say that we scent danger. There is no question that this sense played an important part in the life of primitive man as it does to- day in the preservation of lower animals. It is certain that some insects, at least, if not the majority of them, find their food by the sense of smell. The food-getting instinct is probably the lowest though the most valuable of the instincts, and the sense of smell is surely one of its valuable servants. Touch. The sense of touch is, with human beings, entirely a superficial sense, a contact sense, capable of stimulation FIELD ZOOLOGY. through specialized cells lying just under the epidermis, more abundantly scattered in some portions of the body than in others. We do not feel at all just over the elbow- joint, and much less feebly on the cheek than on the lips. But there are other means of contact sense. Close your eyes and let some friend touch one of the hairs on the back of your hand or arm, and you have the immediate sensation of having been touched. A fine nerve at the base of this hair communi- cated to your brain the stimulus of contact. In this latter way, insects are provided abundantly with the contact sense. (Fig. 5.) Catch a house fly, and you will find a number of stiffish hairs on the surface of the body. Lightly touch one of these hairs, and you may be able to prove to yourself that they are actually tactile hairs. Most insects have these hairs in greater or less abundance. There are hairs on some insects which serve other purposes, such as the stiff hairs on the hind legs of some of the swimming beetles, or the auditory hairs, but possibly even these are contact sense organs in addition to their other use. Where the body wall of an in- sect is thickly chitinized, unless the chitin armor is pierced by one of these hairs, the insect seems feebly, if at all, sensitive to touch. A praying mantis on the desk of the author was exploring a bunch of golden-rod, and was confronted by a woolly bear, one of the hairy brown cater- C.O. FIG. 5. Diagram showing innervation of a tactile hair, ch, chitinized cuticle; hyp, cellular layer of skin; sc, ganglion cell; co t ganglion of central nervous system. (Kellogg, after vom Rath.} SPECIAL SENSES OF INSECTS. 15 pillars with a broad black band around its body. The mantis put up her front feet in the usual attitude and the caterpillar promptly took hold of the tarsi. Nothing happened until the caterpillar bit viciously at the mantis' s foot, when she jerked her foot away and ran off, going on five legs and holding up the sixth, much as a dog holds up an injured member. In an insect the tiny nerve at the apex of the hair runs down under the skin to a knot of nervous matter, and from there a nerve fiber runs to a nerve ganglion for that particular segment on which the hair is located. The ganglion is a part of the whole nervous system, as will be proved by the-fact that the insect may will to run away as the result of this excitation of one of its tactile hairs, or it may will to turn about and show fight. Try this on a caterpillar, removing as far as possible the chance of its seeing you and thus becoming frightened in that way. This is different from the usual conception of the human nervous system, where all impressions are sup- posed to be referred to the forward end of the nerve axis the brain for interpretation. But we are coming to realize, through more intelligent study, that there are plenty of stimuli coming in upon our nervous system, which are interpreted before reaching the cerebrum; in fact, so far as late investigators can determine, some stimuli never reach the brain at all, but pass into action upon being interpreted elsewhere. This, being true, proves again the similarity of life activities. Our life is, at foundation, of the same sort as the life of these sim- pler creatures ; only in us it finds more varied means of expression. i6 FIELD ZOOLOGY. Taste. The taste organs of insects occur in the roof of the mouth and on the mouth appendages, especially on the palpi. (Fig. 6.) As with the human tribe, the substance to be tasted must be dissolved and the solution must be brought into contact with the special taste buds. Hence it is necessary that the insect shall dissolve its food in the mouth fluids; the taste organs, then, are so situated that they can be brought into the mouth to explore the food or to subject the food to trial before it passes into the mouth. It is not likely, however, that insects are com- pelled to depend entirely upon the method of trial and error in choosing their food . This would , of course, be true if the insects were confronted with a kind of food entirely new in the life history of their kind; but where an insect has been hatched into the environment in which its for many generations, it comes into life with inherited tendencies toward foods that have nourished its ancestors, and against foods that its ancestors have found distasteful or harmful, or strange. Perhaps, as with the human family, the sense of taste contributes to the relish or the pleasure incident to the act of eating, and, therefore, to the secretion of the digest- ive juices. However that may be, the palpi may be observed in active motion during the whole time a FIG. 6. Nerve endings in tip of labial palpus of a fish moth. (Kellogg, after vom Rath; greatly magnified.) ancestors have lived SPECIAL SENSES OF INSECTS. IJ grasshopper is devouring its grass blade or the potato beetle its wrinkly potato leaf. This may be watched through a reading glass any day you find a leaf-eating insect at its meals. Hearing. That the fifth of our senses is also possessed by many insects is easier to believe than to prove. Anyone who has ever listened to call and response of half a dozen katy- FIG. 7. Inner aspect of right tympanal sense organ of a grasshopper, Caloptenus italicus. b, chitinous border; c, closing muscle of spiracle; gn, ganglion; m, tympanum; n, nerve; 0, opening muscle of spiracle; p,p, processes resting against tympanum; s, spiracle; tm, tensor muscle of tympanum; v, vesicle. (Folsom, after Graber.) dids, or to two or three cicadas gossiping back and forth on a July afternoon, with their musical "Ah- we ah-we ah-we ah-we-e-e-e-e-e !" does not lack proof in his own mind that insects hear and make answer to what is heard. i8 FIELD ZOOLOGY. FIG. 8. Locust from lateral aspect (left wings removed), showing (ao) auditory organ. (Kellogg.) This may be called negative proof of the power of hearing ; but there is also positive proof in the discovery of the pos- session of auditory organs by many in- sects. (Fig. 7.) Our common grasshop- pers, katydids, crickets, and mosqui- toes have such or- gans. As with the other senses of in- sects, we find the organ of this sense in several different parts of the bodies of these simple animals. The higher animals we call higher because of the centralization of related functions; and that centralization has meant the concen- tration of many formerly distributed senses into one ganglion or knot of our nerve cord the brain. The low animals, then, are the ones in which these senses are most widely separated as to locality and least differentiated as to kind. FIG. 9. Diagram of longitudinal section This might be Said through ^ rst anc * seconc l antennal segments r ' -i , of a mosquito, male, showing complex audi- lurtner:tfie more closely toryorgan compose d of fine chitinous rods, related in point Of pOSl- nerve fibers, and nerve cells. (Kellogg, after tion these Sense Organs Child; greatly magnified.) are to the brain, the higher the insect in the scale of life development. SPECIAL SENSES OF INSECTS. The ear of a locust may be found by first killing one of them, and then clipping off the front and the hind wing from one side of the body, when the ear drum may be seen as a thin, white membrane on the first segment of the abdomen. Underneath this membrane or drum is a tiny sack filled with a liquid, and against the inner wall of this sack rests a fine nerve-ending from which a slender A O B FIG. 10. Antennae of mosquito, Culex pipiens. A, male; B, female. (Folsom.) conducting fiber runs to the ganglion for that abdominal segment. (Fig. 9.) Mosquitoes hear by means of their antennae, on which are thickly distributed many fine hairs whose roots lie in a mass of delicate perceiving matter, composed of chitin rods, nerve fibers, and ganglionated nerve cells, and which give to the mosquito the power of perceiving sounds. (Fig. 10.) CHAPTER III. THE VITAL PROCESSES. Respiration. In insects, as in all animals, a renewed supply of oxygen is necessary to supply the energy used up in all the forms of bodily activity, as well as to analyze the food into tissue-building products. But insects have no lungs, nor any suggestion of an oxygenating center communicating with a blood center where the oxygenation of the food-laden blood is accomplished. Neither does the air enter the insect's body through an opening in the head. Indeed, the respiratory system of an insect is rather a sack closed at the head end. The respiratory system of an insect is much more complex than that of human beings. It consists of a system of air tubes much resembling the windpipe of a bird, but branching so many times as to become delicate enough to carry the air directly to the finest subdivision of any tissue of the insect's body, going in between the eye elements, driving their load of air inside the wing sacks, in between the leg muscles, even down to the delicate tarsal and antennal segments. It is thought by some histologists that the ultimately fine tracheal tubes may enter a cell itself and oxygenate the protoplasm. On account of the usual rigidity of the head and the thoracic segments, the respiratory movements can hardly be noticed in these parts of the body of most insects. But the abdominal segments move much more freely 20 THE VITAL PROCESSES. 21 upon each other, and here the breathing of the insect may easily be studied. Catch a grasshopper, and holding it by the hind legs with the thumb and fore- finger notice the alternate contraction and expansion of the abdomen. With the reading glass, look along the sides of the abdomen, and minute openings may be found, usually outlined with some different color. These are the openings, or rather the entrances, of the respiratory system spira- cles one on either side of the body for each segment of the abdomen. Through these spiracles the balance between carbon dioxid and oxygen must be preserved. Hence, if you wish to kill an insect for your collec- tion box, by means of some poisonous gas, you cannot do it by holding its ^ antenna; bj brain; ^ leg . n , nerv e cord; "nose," but by applying p, palpus; .y, spiracle;^, spiracular or stig- the gas tO its abdomen matal branch ; '> main tracheal trunk; v, and its thorax, where the openings into its respira- tory system are found. (Fig. n.) Inward from each spiracle, a tracheal tube leads to a main trunk of the system, of which there are two, one along each side of the FIG. ii. Trac heal system of an insect. ventral branch ; vs, (Folsom, after Kolbe.) dsceral branch. 22 FIELD ZOOLOGY. body. From this main trunk there arise in each segment three sets of branches: the branch going upward to supply the muscles of the back and the wings ; the visceral branch, running interiorly and supplying the organs of the alimentary tract, the kidneys, and the reproductive organs; and the ventral branch, which carries air to the ventral ganglia, the ventral muscles, and the legs. In some insects these spiracles are protected from dust and other foreign substances much as our noses are, by fine hairs; in others a tiny flap of chitin closes the open- ing; in some others the wing covers bend down over the line of spiracles; but in other insects, as in the order of the bugs, there seems to be no protection whatever. In insects which are very FIG. 12. Lateral gill from abdomen r . n- .1 . A , u XT swift fliers there are, lust of a May fly nymph, Hexagema J variabiiis. Enlarged. (Fohom.) under the chitin body cover- ing, tracheal pockets, or en- largements of these air conductors; these are supposed to be for the storing of a reserve supply of air which may be drawn upon by the insect during the long, swift flights which use up so much oxygen. In aquatic insects, or nymphs of insects which later become air breathers, the spiracles are not present at first, and the animal breathes while in the water by means of tracheal gills, developing the spiracular system much later. These gills present to the water an extensive surface with a thin tegument, and under which the tracheae THE VITAL PROCESSES. 23 branch to form a network of tubes ; through the tegument covering the tracheae the gaseous interchange of carbon dioxid for oxygen takes place. The rate of respiration varies with the activity of the insect, with the temperature, and with other bodily conditions. The respiratory movements are mainly reflex, each thoracic and abdomi- nal ganglion acting as a center for the respiratory move- ments of that particular segment. Circulation of the Blood. In birds and mammals, contact of the blood with the air that is, the combining of the C, H, and O of the fats, the amyloids, and the waste tissue with the oxygen of the air takes place in a localized region of the body, the lungs, from which the oxygenated blood is sent back to the blood center the heart to be driven to all parts of the body. Hence, in these divisions of the animal kingdom, there is a distinct and closed vascular system making a complete double circulation. In insects there is no such vascular system and no definitely prescribed round of the blood in tubes. Just underneath the chitinized dorsal wall of the insect's body, lies a long pulsating organ having several chambers provided with valves; it is open at both ends and at the sides between the chambers. This may be called the heart, and it does not connect with any net- work of tubes carrying foul and aerated blood, as in the human animal; but, instead, its pulsations are so per- formed as to direct the current of blood forward toward the front end of the body, emptying itself in the head, while at the same time the blood then in the posterior end or at the sides is drawn into the long pulsating heart. No air reaches this heart, except such as may remain in 24 FIELD ZOOLOGY. the blood which is then drawn in, hence the blood must be aerated elsewhere. The respiratory system is made to conform to the needs of this rudimentary vascular system. The tracheae, penetrating as they do the intra- muscular spaces of the body, provide the means for bringing the air into contact with the blood. The blood bathes all the tissues of the body, fills all spaces not filled by the organs, and even bathes the cells of those organs; hence, wherever a trachea empties out its air, the blood there present is oxygenated. The general blood movement is, then, forward through the tissues, till it finally works its way around through the general body spaces and passes backward, following the body contour lines, to re-enter the heart again at its rear or sides. Alimentation. In man, the alimentary canal, beginning at the mouth, is modified into mouth, oesophagus, stomach, small intestine, large intestine, with the familiar three modifications of the last-named, the unassimilated residue finding exit at the anus. In different parts of this long canal are secreted and discharged into the food there present, the various fluids whose function is the reduction of the solid foods taken, to liquid form, suitable for the building of new body cells or the rejuvenation of over- worked cells. This process of reduction is diges- tion, and the various fluids may be named: as saliva, whose active principle is ptyalin; pepsin, trypsin, pan- creatin, steapsin, etc. In insects the simplest alimentary canal is that of the primitive insects, in which it is merely a nearly straight tube, constricted at either end, and enlarged in the middle into a main digestive cavity with muscular THE VITAL PROCESSES. walls; this latter corresponds to our stomach. It is separated from the fore and hind portions of the canal by rudimentary valves, which are simple ex- trusions of the wall of one cavity into the opening of the next cavity, and whose loose edges prevent the return of mate- rial. In such insects the food is soft as to its substance and not varied in its nature. Hence there is no need of special gland- ular extensions of the canal. In insects whose food is of more solid nature or more varied in its charac- ter, more modifica- tions of the canal are necessary for the se- cretion of fluids needed in the diges- - . 1 FIG. 13. Digestive system of a beetle, Carabus. tion of particular por- a> anal gland . c (of fore gut)> crop . c (of hind of the food, and gut), colon, merging into rectum; d, evacuating duct of anal gland; g, gastric caeca; i, ileum; m, mid intestine; mt, Malpighian tubes; o, cesoph- for the retention of the food long enough agus; p, proventriculus; r, reservoir. (Folsom, to let it become a f ter Kolbe ^ thoroughly permeated with these fluids. In many insects this is accomplished by the crop and the proventriculus, 26 FIELD ZOOLOGY. two extensions of the canal between the oesophagus and the stomach. (Fig. 13.) In the human being the food is mixed with the saliva while it is in the mouth ; in the bird, the food is swallowed dry or whole, and this mixing with the saliva is accom- plished in the crop. Peptonization is accomplished for birds and for many insects by a second enlargement, which has already been spoken of, just below the crop. In insects, the salivary glands may be restricted to the head and the saliva be discharged from there into the mouth; or the glands may extend backward into the thorax. In connection with the salivary glands, there may be poison glands in such insects as are predatory or carnivorous, and also in spiders. In the honey bee and the honey ant, also, this crop or . fore-stomach serves as a temporary storage cavity for the liquid foods which have been eaten by the bee or the ant, or brought to the nest bee or ant by some foraging bee or ant. The cavity is separated from the true stomach by extruding flaps or outfoldings of its walls into the cavity of the true stomach; and the food swallowed is thus kept indefinitely or let out either forward or back- ward by the voluntary effort of the insect. Such insects, like some birds, feed their young by regurgitation. Such preparation of the food as part of the alimentation of the parent is evidence of their high position in the scale of life, and of their close relationship to the mammals, the highest of the animal kingdom. In carnivorous insects this crop is a dilation of the canal axis; but in the Neuroptera and the butter- flies, bees, wasps, ants, and the flies, this salivary extension of the canal is a lateral pocket, and serves in all of them for the temporary storage of food just THE VITAL PROCESSES. 27 swallowed until it can be thoroughly mixed with the digestive fluid. The stomach of an insect, instead of serving as does our stomach, as a means of separating the solid foods into minute portions as well as mixing them with the pep- sin, is more like an intestine; it has not the capacity for strong muscular action, such as has the preventriculus or gizzard. Considerable secretion of digestive fluids takes place here, as well as the absorption of the prepared food mass. The portion of the canal behind the stomach is, in some insects, modified into regions much like the divisions of the large intestine of the human animal, and named like them, colon, ileum, and rectum. In the primitive insect there are no such divisions apparent ; and in many others the colon or first division is absent. In human alimentation the food current, in process of elaboration, is supplied by the mesenteries with the amoeboid cells, which play so important a part in the maintenance of the health of the body by devouring the microbes of various diseases. In many insects this function seems to be performed by cells of the lining wall of the stomach, which become free by constriction and float out free in the food current. The excretory function of the kidneys seems to be discharged by the Malpighian tubes of the insect, which open into the intestine behind the stomach. In the human animal there is no aeration of the food current until, after having been gathered from the capillaries of the stomach and the intestines, from the lacteals, and from the liver, into the right side of the heart, it is sent to the lungs where it is oxygenated, and, being returned to the left side of the heart, it is sent to all the waiting tissues 28 FIELD ZOOLOGY. of the body. But in insects, so far as investigation has shown, the aerating system of air tubes touches the ali- mentary canal only at the region where the Malpighian tubes are liberally supplied with tracheae. In the human body, waste liberation is accomplished through the lungs (gaseous) and through the kidneys (liquid). In insects, through the aeration of the Malpighian tubes, that is the kidney region, the two sorts of waste liberation may reinforce each other. As to the remaining waste libera- tion, not accomplished by the Malpighian tubes, the fat body of the insect, lying along the alimentary canal and the dorsal heart, also acts as a waste eliminator, and in some insects acts as a storage tract for the deposit of waste ; especially is this true where the insect is a primitive insect and there are no Malpighian tubes. The blood of insects, which is more like the lymphatic fluid of the human animal, contains many fat globules, indicating a connection between this fat body and the circulation of the blood. Nervous System. The nervous system of the larva of an insect, if we select an insect having complete metamorphosis, as a butterfly, is a type of a simple nervous system, one nervous ganglion for each segment of the body, joined by a double cord, and lying in the middle line of the body ventrally. As the adult stage is approached, there is more or less of fusing of these ganglia in all the different orders of insects; but in an adult butterfly the front end of the nerve chain becomes modified into two ganglia, one lying a little forward called the brain or cephalic ganglion, and the other lying a little below the brain and called the suboesophageal ganglion. The brain supplies THE VITAL PROCESSES. 29 with nerves the simple eyes, the compound eyes, and the antennas. The subcesophageal ganglion sends nerves to the mouth parts, and is itself connected with the brain by a pair of cords between which the oesophagus passes. On back from the subcesophageal ganglion the nerve chain passes into the thorax, where there is one fused ganglion representing several larval segments. This FIG. 14. Stages in development of nervous system of a water beetle. Mcilius sulcatus; showing ventral nerve cord in earliest larval stage, and, 7, the system in the adult. (Kellogg, after Brandt; much enlarged.) supplies with nerves the wings, the legs, and the many thoracic muscles. In the abdomen there is usually one ganglion for each segment, the nerve chain terminating in several fibrillae in the last segment. (Fig. 14.) Lying above the oesophagus, and having its origin in front of the brain, there lies the sympathetic system. This, by means of two pairs of ganglia, controls those activities which are safely automatic respiration, the action of the dorsal heart, and the usual processes of 3