LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 GIFT OF 
 
 &',M 
 
 Received cj- . , 1900 
 
 Accession No. /2 $ . Class No. - 
 
 *i 
 
LABORATORY MANUAL 
 
 FOR THE COURSE IN 
 
 ELEMENTARY AND ECONOMIC 
 
 ENTOMOLOGY 
 
 AT THE 
 
 UNIVERSITY OF CALIFORNIA 
 
 C. W. WOODWORTH 
 
 Published by the Author 
 BERKELEY, CAL. 
 
 1893 
 Copyrighted. 
 

T 
 
 FIRST WEEK. Vo*, 
 
 NEEDED.* A number of grasshoppers. 
 
 FIRST HOUR. Draw one of the legs, naming the parts as follows: 
 Coxa, trochanter, femur, tibia, tarsus (three-jointed). Describe the 
 nature of the union between each of these parts. Compare each of 
 these parts in the three pairs of legs, and note particularly: (a) Strength- 
 ening ridges, () modifications of the surface for the attachment of 
 muscles, (c) guidepieces at the joints, (d) position and use of spines, (<?) 
 pads on the feet the one at the end is called the pulvillus, (/) claws 
 on the feet ungues. Note the number of joints in the antenna, the 
 two basal ones (scape and pedicel) somewhat different from the remain- 
 ing part flagellum. Indicate the character of the union between these 
 parts. Examine the eyes and the simple eyes ocelli, describing their 
 shape and position. 
 
 SECOND HOUR. Remove the head and pin it against the cork 
 holder. Observe the palpi. Note the number of joints in each pair. 
 Observe the lips above or in front labrum, on the sides galeae, 
 and below labium. Draw the whole labium indicating the mentum, 
 ligula, palpi and the lobes lips proper. Remove the labium, 
 exposing the maxillae. Draw one of these, naming the parts as fol- 
 lows: Cardo, stipes, palpifer, palpus, galea, lacinea. Examine the 
 large jaws mandibles, beyond the maxillae, and the small basal piece, 
 and also the clypeus to which the labrum is attached. 
 
 THIRD HOUR. Insert a blunt pin into the hind end of the insect, 
 pushing it forward until it comes against the front of the head, stretch- 
 ing the neck well out. Observe now the parts of which the head is 
 composed, and indicate the relation of these parts to the appendages. 
 Attempt to trace by semi-diagramatic drawings the relation between 
 labium and maxillae and between all the appendages of the head and 
 legs. 
 
 *The following material is needed throughout the course: 
 
 Magnifier. A Coddington or other lens of about a half-inch focus. 
 
 Cyanide bottle. A small lump of cyanide of potash cemented to the bottom of an 
 eight ounce salt-mouth bottle in plaster of Paris. 
 
 Pins. Klajger insect pins Nos. 1, 3, and 5 are recommended, but ordinary pins do for 
 dissecting. 
 
 Cork holder. A wine or other large cork to pin the insect to while studying. 
 
. 
 
SECOND WEEK. 
 
 NKEDED. A number of grasshoppers. 
 
 FIRST HOUR. Examine the front wing, noticing the strong vein 
 extending to the base (subcostal vein) , and also the other strong vein 
 (median vein), which, with the subcostal vein, divides the wing into 
 three more or less equal parts. Notice further the costal vein, inde- 
 pendent vein, and submedian vein within these areas. Draw an out- 
 line of the wing, naming these parts costal, median, and internal 
 areas, and sketch in roughly the veins and their branches. Now on a 
 larger scale draw the base of the wing, indicating accurately the num- 
 ber and origin of each vein in this region. 
 
 SECOND HOUR. Draw one of the hind wings in the same way as 
 directed above for the front wings, marking out very carefully the ho- 
 mology of the veins with those of the front wings. 
 
 THIRD HOUR. The three segments of the thorax are called the 
 pro- meso- and metathorax,and the same prefixes are used to designate 
 the parts of each of these segments. Above they are called tergum or 
 notum, the sides plurae, and beneath sternum. The notum is divided 
 into four tergites (praescutum, scutum, scutellum, and postscutellum), 
 the pleurae into twopleurites (episternum and epimeron), and the ster- 
 num of each segment contains but a single sternite. Describe or draw 
 these parts as they appear on the grasshopper, noting particularly: (a) 
 The great size of the pronotum, () the absence of the praeepimeron, (<:) 
 the small size of the prosternum, and (d) the dovetailing between the 
 sternites of the second and third thoracic and first abdominal segments. 
 
THIRD WEEK. 
 
 NEKDED. A number of grasshoppers, including both sexes. 
 
 FIRST HOUR. Study the union of the wing with the body. Make 
 a drawing both from above and below. Examine the wing in all posi- 
 tions, and describe the action of the hinge parts. 
 
 SECOND HOUR. Draw the first two abdominal segments, making 
 out carefully the division between the thorax and abdomen. Draw on 
 a larger scale the ear. Notice the chitinous border of the tympanum, 
 and note the shape and position of the lateral and central processes of 
 the tympanum. Notice the spiracle near the front edge of the ear, and 
 note the position of all the spiracles on the insect's body. 
 
 THIRD HOUR. Male. Draw carefully the end of the abdomen as 
 seen from the side, numbering all the parts so as to indicate the seg- 
 ments to which they appertain. Now, grasping the abdomen near the 
 thorax, slowly compress it until the organs are widely spread, and draw 
 again. Note the cerci, the three anal flaps and the clasping organ. 
 Female. Draw twice from the side, as directed above, noting the cerci, 
 the anal flaps, the four valves of the ovipositor, the egg guides and the 
 extensile glands between the eighth and ninth segments below. Try 
 to homologize the parts in the two sexes. 
 
FOURTH WEEK. 
 
 NEEDED. A sauce dish. Some pasteboard cut so as to lay in the 
 bottom of the dish. A sharp-pointed knife or small sharp-pointed scis- 
 sors. A number of grasshoppers. 
 
 FIRST HOUR. With scissors or knife rip the insect open along 
 the side from end to end, then putting a pin through the head and an- 
 other through the harder part of the hind end of the body, stretch the 
 insect out full length on a piece of pasteboard, putting in the pins very 
 obliquely. With other pins spread out the body, exposing all the in- 
 ternal structure, and place the whole under water in the sauce dish. 
 Observe the digestive tract, the air sacs, the sexual organs in the abdo- 
 men, the tracheae in all parts of the body, and, pulling the alimentary 
 tract to one side, notice the heart. Notice further the nervous system 
 along the sternum and the muscles of the thorax. Carefully dissect 
 out the digestive system, noting the pharynx, with the salivary glands, 
 the aesophagus, the crop, with the caeca, the stomach, the ilium, with 
 the Malpighian tubes, the colon, and the rectum, with the rectal glands. 
 
 SECOND HOUR. Dissect out the sexual organs of both sexes, de- 
 scribing their structure. Describe the size and position of the principal 
 air sacs. Dissect out and describe the prominent parts of the nervous 
 system in the body. 
 
 THIRD HOUR. Carefully separate the head from the body, and 
 cut the wall of the head, beginning at the mouth and running back of 
 the eyes, removing the back part. Now pin the head to pasteboard, 
 and, putting it into water, make out carefully the brain, drawing and 
 describing it. 
 

 FIFTH WEEK. 
 
 
 NEEDED. A number of rather large-sized beetles. 
 
 FIRST HOUR. Dissect out and draw the mouth parts of at least 
 two species. Compare with each other and with those of the grass- 
 hopper. Consult the introduction to LeConte and Horn's Classifica- 
 tion of Coleoptera. 
 
 SECOND HOUR. Draw the under side of the thorax of at least 
 two species, naming all the parts, and compare them with the corres- 
 ponding parts of the grasshopper. 
 
 THIRD HOUR. Describe the beetle according to the following 
 outline: 
 
 Whole insect 
 Head 
 
 Appendages 
 Thorax 
 
 Appendages 
 Abdomen 
 
 ACCORDING TO 
 
 'Size 
 Color 
 
 Markings 
 Shape 
 
 Sculpture 
 
SIXTH WEEK. 
 
 NEEDED. Dissecting apparatus as for the fourth week. A num- 
 ber of butterflies or moths and caterpillars. 
 
 FIRST HOUR. Carefully study and describe the mouth parts. 
 Draw the venation of both front and hind wings of one or more species. 
 Indicate the homology between the veins in the wings of these insects 
 and those of grasshoppers. For the peculiar terms used in this order, 
 compare the introduction of Morris' Synopsis of I^epidoptera . 
 
 SECOND HOUR. Denude the thorax of its scales, study and draw, 
 naming the parts exposed. (The scales are much more readily re- 
 moved from moths than from butterflies.) 
 
 THIRD HOUR. Describe the peculiarities of external structure of 
 a caterpillar. If the caterpillar is hairy, remove the hairs with the 
 scissors. Lay open the body as directed in the fourth week, and com- 
 pare the internal structures with those of the grasshopper. 
 
SEVENTH WEEK. 
 
 NEEDED. A few slides and covers and a number of wasps. 
 
 FIRST HOUR. Make careful dissections and drawings of the 
 mouth parts, comparing them with these already studied. For this 
 study, the labium and maxilla is best seen mounted in water on a slide. The 
 part should be dissected out and placed upon a small drop of water on 
 the center of the slide, and the cover glass laid on. Only enough water 
 to fill the space between the cover and the slide is wanted. 
 
 SECOND HOUR. Make careful drawings of the wings, making 
 out the homology of those so far studied, and also naming the veins 
 according to the peculiar nomenclature used in this order. Compare 
 the introduction to Cresson's Synopsis of Hymenoptera. 
 
 THIRD HOUR. Study the thorax drawing, and name the parts. 
 ELECTIVE WORK. Description. 
 
 Weeks twelve to sixteen, either wholly or in part, may be devoted 
 to writing descriptions of insects. One insect should be described each 
 week. The descriptions should be full and accurate, and consist of: 
 
 1 . Name. 
 
 2. Short description consisting of: (a) Size, () general color, (c) 
 striking peculiarities. 
 
 3. Full description, beginning at the head and taking up each part 
 in detail. 
 
 4. Notes on habitat, etc. 
 
 5. Number of specimens studied. 
 
 Before writing the description, carefully read at least two recent 
 descriptions of closely related insects, and use the same nomenclature. 
 It is well to illustrate by figures, but the description should be com- 
 plete in itself, and not depend upon the figures. The important thing 
 in writing a description is to distinguish the things which characterize 
 the insect as a species from those, on the one hand, which are common 
 property of the whole group, and, on the other, are peculiar to the 
 specimen or variety. This becomes much more easy to do when a 
 large number of specimens are studied, both of the species and of related 
 species. In collecting, therefore, for this purpose take, whenever pos- 
 sible, many of the same kind. In writing a description it often be- 
 comes necessary to mutilate a specimen. The description should be 
 accompanied, however, with at least one perfect specimen. 
 
EIGHTH WEEK 
 
 In this and the three succeeding weeks twelve species are to be de- 
 termined as nearly as may be with the available literature. This 
 twelve must include at least one of each of the following orders: Hy- 
 menoptera,Lepidoptera, Diptera, Coleoptera, Hemiptera and Orthofftera. 
 Make notes and drawings freely while making the determinations, and 
 note particularly the publications used and the results obtained. 
 
 HYMENOPTERA. Cresson's Synopsis is the basis for determina- 
 tions in this order. Consult also manuscript synopses of particular 
 groups. For a reference to the described species compare Cresson's 
 Catalogue of the species of Hymenoptera. 
 
 LEPIDOPTERA. Use Morris' Synopsis of Lepidoptera for the groups 
 represented therein. Consult Smith's List of Lepidoptera and also 
 manuscript synopses and lists. 
 
 DIPTERA. Williston's Synopsis of Diptera. For the genera of 
 Orthorapha not in Williston see manuscript synopsis. For Cyclorapha 
 use Schiner's Fauna Austraica. For species consult Osten Sacken's 
 Catalogue of Diptera and manuscript additions. 
 
 NEUROPTERA. Use Hagen's Synopsis of Neuroptera. 
 
 COLEOPTERA. For genera use LeConte and Horn's Classification 
 of Coleoptera and for species compare Henshaw's Lists of Synopses and 
 his Checklist. 
 
 HEMIPTERA AND PHYSOPODA. Use synopsis in Comstock's In- 
 troduction to Entomology and also manuscript synopses and lists. 
 Compare Uhler's Checklist of Heteroptera and manuscript list of Hom- 
 optera. 
 
 ORTHOPTERA. Use synopsis in Comstock's Introduction to En- 
 tomology and manuscript synopses and lists. 
 
 PSEUDONEUROPTERA. Use Hagen's Synopsis of Neuroptera. 
 
 THRYSANURA. Use synopsis in Comstock's Introduction to En- 
 tomology. 
 
 ELECTIVE WORK. Determination. 
 
 The twelfth to sixteenth weeks may be partly or wholly used for 
 further determinations. It is recommended that the student devote him- 
 self to as small a group as possible. Three species should represent 
 each week's work. 
 
NINTH WEEK. 
 
 Three specimens of insects should be determined this week. For 
 directions see under eighth week. 
 
 ELECTIVE WORK. Physiology. 
 
 If this work is elected, the whole of one of the following groups 
 must be done: 
 
 GROUP i. Walking. Needed: (a) For blueprinting: solution of 
 citrate of iron and ammonia, one part to four of water; solution of red 
 prussate of potash, one part to six of water; dish for sensitizing bath, 
 some plain paper not too highly sized. () For tracings: A candle, 
 some small panes of glass; (V) for loading: a little wax or soft paraffin, 
 some shot of rather large size; \d) for experimenting with, a number of 
 insects of the same species and of rather large size. 
 
 TWELFTH WEEK. Sensitize some paper by wetting one side of it 
 with a mixture of equal parts of the above solutions and drying. This 
 should all be done in the dark room. Blacken a sheet of glass by hold- 
 ing it over the burning candle. Lay the blackened glass on the table, 
 and cause an insect to walk over it, and take a blue print copy of the 
 tracing thus obtained. Illustrate by diagramatic sketches the method 
 of walking as made out by a study of the tracings. Fasten a blue print 
 of the tracing into the book. 
 
 THIRTEENTH WEEK. Repeat the above, but with mutilated spec- 
 imens, showing the method of walking with five and four legs instead 
 of the normal number. 
 
 FOURTEENTH WEEK. Melt a little of the wax or paraffin and 
 place a drop on one end or side of the insect experimented with, and 
 imbed in it one or more shot so as to weigh the insect down on that 
 side or end. Obtain tracings as above and compare the results with 
 normal walking. Repeat once or twice with the load at different 
 places. 
 
 FIFTEENTH WEEK. Obtain tracings of the same species on in- 
 clined surfaces and compare with the loaded and with the normal walk- 
 ing. 
 
 SIXTEENTH WEEK. Obtain tracings showing a change in locomo- 
 tion due to a sensation, as a touch or sound, and compare the tracings 
 before and after the change as well as the transition. 
 
 GROUP II. Flight. Needed: A pair of small sharp-pointed 
 scissors, some wax or soft paraffin, some small shot, India ink, a small 
 camel's hair pencil, a vial of chloroform, a number of house flies. 
 
 TWELFTH WEEK. Cut off an equal amount from both wings of a 
 fly, and, allowing it to escape with a normal fly, note the effect of 
 the mutilation. Repeat two or three times, clipping off different relative 
 amounts, but always the same on the two sides. Repeat two or three 
 times, taking parts off from the back edge only. 
 
 THIRTEENTH WEEK. Repeat the above experiments, mutilating 
 only one side, and note results. 
 
TENTH WEEK. 
 
 Three species of insects should be determined this week. For di- 
 rections see under sixth week. 
 
 ELECTIVE WORK. Physiology (con.) 
 
 FOURTEENTH WEEK. Observe and note the effect of loading the 
 body with shot and the tip of one and both wings with wax or paraffin. 
 
 FIFTEENTH WEEK. Remove one and both halters and note the 
 result. Darken the ocelli with India ink. and note results. Darken 
 also one and both eyes, and both eyes and ocelli. Note particularly 
 the significance of these results. 
 
 SIXTEENTH WEEK. Slightly chloroform a number of flies and 
 compare their flight with the normal, and also observe the effect of plac- 
 ing flies a short time in a cyanide bottle. Note particularly the signif- 
 icance of these results as compared with the preceding experiments. 
 
 GROUP III. Sensations. Needed: Blue printing and tracing 
 materials as in group one, but larger-sized sheets, at least twelve in- 
 ches square. A set of blocks Ixlx^ inches in size twelve white, 
 twelve black, six red, six blue, six yellow and six green. A box 
 divided into six equal sections by partial partitions, with a set of glass 
 covers for these partitions six clear, six black, one red, one yellow, one 
 blue and one green. A musical instrument. A set of vials containing 
 different odors. A quantity of insects of various kinds. 
 
 TWELFTH WEEK. Blacken a sheet of glass and arrange the 
 black and white blocks on it to form a labyrinth, so that an insect 
 set in the middle cannot see out. Set in w a light where the 
 blocks will cast distinct shadows and liberate an insect in the center. 
 The tracing it makes indicates to some extent its sight perception. 
 After the tracing is made mark the outline of the shadows with a pin 
 and also the outlines of the blocks, writing as well the color of each. 
 Now take a blue print of the tracings and note the significance of the 
 various parts. 
 
 THIRTEENTH WEEK. Repeat the above, but with the labyrinth 
 composed of blocks of all colors to determine the relative color percep- 
 tion. 
 
 FOURTEENTH WEEK. Arrange the colored plates over the sec- 
 tions of the box and liberate a number of insects, first in one and then 
 in another, and after a short time note in what compartments they are to 
 be found, and thus determine for each insect its color preference. 
 
 FIFTEENTH WEEK. Place an insect where it can be carefully 
 watched, and then sound different tones on the musical instrument and 
 note any evidence of sound perception. Determine for those evincing 
 this perception the pitch producing the most effect and see if the in- 
 strument produces notes in either direction beyond their power of per- 
 ception. 
 
 SIXTEENTH WEEK. Cover the sections of the box with all black 
 or all clear glass, according to the nature of the insects experimented 
 with, and place in each an open vial containing an odor. Now by 
 liberating a number of insects, first in one and then in another, their 
 odor preference may be determined. 
 
ELEVENTH WEEK. 
 
 Three species of insects should be determined this week. For di- 
 rections see under eighth week. 
 
 ELECTIVE WORK Physiology (con.) 
 
 GROUP IV. Effect of temperature. Needed: A number of ther. 
 mometers. A box with glass cover. A watch or metronome. A 
 musical instrument. A number of small potted plants and lamp globes. 
 Insects, some with a visible heart, some with evident respiratory 
 movements, some with sound perception, and some plant lice. 
 
 TWELFTH WEEK. Carefully note the temperature and count the 
 heart beat. Place the insect and the thermometer in the box and set 
 upon the stove. After raising the temperature about 10 degrees F. re- 
 move and wait till the thermometer begins to fall, and count again the 
 heart beat Repeat, raising the temperature about ten degrees at a time 
 until it has become uncomfortable for the insect. If time remains, con- 
 tinue the observations while the box is cooling at each temperature be- 
 fore observed. 
 
 THIRTEENTH WEEK. Repeat the above, counting the respiration 
 beats instead of those of the heart. 
 
 FOURTEENTH WEEK. Repeat the above, countig nthe time re- 
 quired by a plant louse to walk over a certain distance under the differ- 
 ent temperatures. 
 
 FIFTEENTH WEEK. Try to discover if there is any difference due 
 to the temperature in (a)acuteness of sound perception, ()pitch of best 
 perception, and (r)range of sound perception. 
 
 SIXTEENTH WEEK. The work of this week should be started at 
 least six weeks before the end of the term. Make a number of breeding 
 cages, as directed under Life History Work, using, if possible rooted 
 plants. Put in each a thermometer and a newly born plant louse. One 
 cage should be placed out-of-doors, another in a living room, and a 
 third, if possible, in a still warmer place. It would be well to have two 
 in each place to allow for accidents. The thermometers should be read 
 three times a day as regularly as possible, and the insects examined. 
 At the end of six weeks the relative condition of each cage should be 
 carefully noted. 
 
TWELFTH WEEK. 
 
 The work of this and the following weeks is to be selected from 
 the work laid down as elective work in this manual. If work in phys- 
 iology or morphology is elected all five weeks must be devoted to a sin- 
 gle group in one of these subjects. Other work may be taken in any 
 combination of one-week units. The directions for elective work will 
 be found as follows: 
 
 Description under week seven; 
 
 Determination under week eight; 
 
 Life history under week twelve; 
 
 Field work under week thirteen; 
 
 Physiology under weeks nine to eleven; 
 
 Morphology under weeks fourteen to sixteen. 
 
 ELECTIVE WORK. Life History. 
 
 The laboratory work of weeks twelve to sixteen may be repre- 
 sented by investigations upon the life histories of insects. From the 
 nature of this work it cannot generally all be done during these weeks, 
 but should be begun earlier. Three transformations will be considered 
 equivalent to a week's work. Each stage should be represented by a 
 short descriptive note or sketch and by a properly mounted specimen. 
 Thus four stages of one insect would represent a week's work, as 
 would two stages of each of three insects. Parasites will be counted 
 as though they were stages of the insect studied. 
 
 Eggs may be hatched by placing them in a dry vial, stoppered and 
 labeled, or they may be at once placed in breeding cages, as described 
 below. 
 
 Larvae and nymphs, if vegetable feeders, may be kept in a breeding 
 cage made as follows: A twig of the food plant is placed in a flowerpot 
 filled with moist sand and covered by a lantern or lamp globe which is 
 closed above with a piece of cloth tied on. If the larvae are young it 
 may be necessary to renew the food from time to time. Another 
 method is to enclose the insect in a cheese-cloth sleeve tied over the 
 twig upon which it feeds. A third way is to watch the insect as it oc- 
 curs in nature, being very careful that there is no mistake in identity. 
 Carnivorous forms must be supplied with their appropriate food, but 
 practically the same method may be used. 
 
 Pupae are best kept in tight boxes, which should be of a size suffi- 
 cient to allow the full expansion of the wings. 
 
 Adults can often be made to lay their eggs, sometimes by simply 
 confining the females in a box; generally, however, it is best to confine 
 her in a breeding cage with the appropriate food for her young. 
 
THIRTEENTH WEEK. 
 
 The work of this week is elective. For directions see under 
 twelfth week. 
 
 ELECTIVE WORK. Field Work. 
 
 NEEDED. Slides, covers, glycerine jelly, alcohol, oil of cloves, 
 and balsam. 
 
 TWELFTH WEEK. In the field: Search for a plant affected with 
 large scale insects. Note the general appearance of the affected plant. 
 Note the abundance and distribution of the scale insects on the plant. 
 Look for evidences of parasitism and work of predaceous insects, collect 
 any specimens that may show such work and also twigs containing 
 normal scales. In the laboratory: Look for eggs and young and con- 
 tinue the search for parasites. Mount the eggs and young if found, in 
 glycerine jelly, as follows: With the point of a penknife pick out a piece 
 of jelly about one sixteenth of an inch in diameter and place on the center 
 of a slide. Upon this place the insect to be mounted and lay on the cover 
 glass and gently heat until the jelly becomes fluid. Examine under 
 the microscope and describe briefly. Determine the species by U. S. 
 Agr. Report for 1880. 
 
 THIRTEENTH WEEK. In the field: Search for a plant affected 
 with small whitish scales and do as directed above for the large scales. 
 In the laboratory: Mount specimens of the insects from beneath the 
 scales in glycerine jelly, as directed above, and in Canada balsam, as fol- 
 low: Place the insects in alcohol five minutes and then in oil of cloves 
 about the same length of time. Now put a small drop of balsam on 
 the center of the slide and the insect upon it, and cover. Warm gently 
 as before. Determine the species by U. S. Agr. Report for 1880 and 
 Cornell University Report for 1882. 
 
 FOURTEENTH WEEK. In the field: Turn over a piece of sod 
 with a spade and carefully pick the earth to pieces searching for root- 
 feeding larvae. Look for and note any evidences of injury, and collect 
 specimens. In the laboratory: Determine, as nearly as possible from 
 books and the collection, the grcup of the insects found and make a 
 brief descriptive note of each. Properly mount and label each specimen. 
 
 FIFTEENTH WEEK. In the field: Look for a tree or fallen log 
 affected with borers; collect specimens of the insects and of their 
 work. In the laboratory: Determine, as nearly as possible, the insects 
 collected. Make a descriptive note of the insects and sketches showing 
 their work. Properly mount and label the material collected. 
 
 SIXTEENTH WEEK. In the field: Look for a leaf-eating or fruit- 
 eating insect and collect specimens. In the laboratory: Determine, 
 mount and note as above. 
 
FOURTEENTH WEEK. 
 
 The work of this week is elective. For directions see under 
 twelfth week. 
 
 ELECTIVE WORK. Morphology. 
 
 If this subject is elected the whole of one of the following groups 
 must be done: 
 
 GROUP I. Venation of grasshopper wings. Needed: Slides, 
 large covers, alcohol, oil of cloves, Canada balsam, a number of 
 grasshoppers. 
 
 Mount all the wings of at least twelve grasshoppers in balsam, as 
 directed under field work, being very careful to note on each slide the 
 source of each wing, also mount and label the specimens from which the 
 wings were taken. 
 
 THIRTEENTH WEEK. Make careful drawings of the front and 
 hind wings, showing the principal veins in the two most different 
 species. 
 
 FOURTEENTH WEEK. Compare the two sides of each insect and 
 describe the amount and nature of the differences. 
 
 FIFTEENTH WEEK. Compare the wings of different specimens 
 of the same species, describing the amount and nature of the differences. 
 How do these variations compare with those found in the two sides of 
 the same specimen ? 
 
 SIXTEENTH WEKK. Compare the wings of different species, 
 describing the amount and nature of the differences. How do these 
 compare with those within the species ? 
 
 GROUP II. The tongue of the house fly. Needed: Test tube or 
 beaker, a number of vials, needles in handles, camel' s-hair pencil, 
 alcohol, borax carmine solution, acid alcohol, oil of cloves, Canada 
 balsam, slides, covers, paraffin bath, label, plate of glass, microtome, 
 Schallibaum's fixative, microscope, and a number of house flies. 
 
 TWELFTH WEEK. Heat water to boiling, and after removing 
 from the fire, drop into it the freshly -removed heads of a number of flies. 
 After three minutes remove the tongues from the head, leaving the 
 former a half an hour in 50% alcohol. They are then placed in strong 
 alcohol for one hour and then left over night in borax carmine. In the 
 morning they are washed in acid alcohol and then placed in strong 
 alcohol till next week. Treat some others in hot water and then remove 
 and mount the tongues in balsam, as directed under field work. 
 
FIFTEENTH WEEK. 
 
 The work of this week is elective. For directions see under 
 
 twelfth week. 
 
 ELECTIVE WORK. Morphology (con.) 
 
 THIRTEENTH WEEK. The tongues stained last week are removed 
 to fresh strong alcohol a few minutes, then to oil of cloves about two 
 minutes, until they have become uniformly somewhat clear. They are 
 now put into barely melted soft paraffin (50 C.) for one-half hour, then 
 for one hour into harder (55 C.) Ladle out onto a wet cold plate of 
 glass, so as to form thick drops with a tongue in the middle of each. 
 After they are thoroughly cool trim into rectangular blocks and fasten 
 one by means of a hot knife blade to the object holder of the microtome 
 in such a position as to cut cross sections. Cut as thin as possible, ad- 
 justing the temperature of the room to the hardness and thickness of the 
 section, so that, while the sections will not wrinkle, they will stick to- 
 gether and form a perfect ribbon. Keep the order of every section 
 very carefully should the ribbon break. Mount as follows: Paint a thin 
 layer of Schallibaum's fixative on a slide. Arrange the sections in the 
 order cut, using two slides if one is not enough. Place in the oven of 
 the bath at 55 C. five minutes. Wash while hot with turpentine and 
 apply the balsam and cover at once. 
 
 FOURTEENTH WEEK. Cut and mount two more sets of section 
 longitudinally and at right angles to each other. 
 
 FIFTEENTH WEEK. Draw carefully the whole tongue from two 
 directions. 
 
 SIXTEENTH WEEK. Draw the two most comprehensive longi- 
 tudinal sections and a number of cross sections and indicate on the 
 other drawings the approximate place of these. 
 
 GROUP III Developmentoftheplantlou.se. Needed: Salt so- 
 lution, alcohol, oil of cloves, balsam, glycerine jelly, a watch glass, 
 needles in handles, slides, covers, microscope, a number of plant lice. 
 
 TWELFTH WEEK. Dissect in salt solution a full-grown plant louse, 
 isolating the ovaries. Mount in glycerine jelly as directed under field 
 work and examine under the microscope to see if the embryos are whole 
 and sufficiently separated from each other and from the other tissue. 
 Mount a good number of slides. 
 
 THIRTEENTH WEEK. Dissect as above and mount in balsam a 
 number of slides. 
 
 FOURTEENTH WEEK. Study the slides and pick out a series of 
 about six stages in jelly and in balsam, showing the development of 
 the young louse. Compare Mark. Die Pflanzenlause. 
 
 FIFTEENTH WEEK. Draw the three smaller stages, naming all 
 the parts which can be recognized. 
 
 SIXTEENTH WEEK. Draw the older stages as above. 
 
SIXTEENTH WEEK. 
 
 The work of this week is elective. For directions see under 
 twelfth week. 
 
 ELECTIVE WORK. Morphology (con.) 
 
 GROUP IV. The cranium of the wasp. Needed: A small beaker. 
 A wash bottle. A pair of small sharp-pointed scissors or sharp-pointed 
 knife. A number of wasps. 
 
 TWELFTH WEEK. Put about a dozen heads to soak in the beaker, 
 and let them macerate for two weeks. Take other specimens and care- 
 fully study the external structure, drawing from above and from before, 
 paying particular attention to traces of nearly obliterated sutures. 
 
 THIRTEENTH WEEK. Draw and study the head very carefully 
 from the side and from behind. 
 
 FOURTEENTH WEEK. Take the material that has been soaking, 
 and with the wash bottle clean out the inside. Remove carefully the 
 mouth parts and antennae. Put the specimens all to soak again, taking 
 them out only as needed. Take a specimen, and from the neck open- 
 ing cut through the head below the eyes and antennae. Dry and study 
 the internal configuration of the crown, comparing it with the outside. 
 Study several specimens. 
 
 FIFTEENTH WEEK. Cut up the side of the head from the mouth 
 opening through the eyes, and study carefully the internal configura- 
 tion of the face. 
 
 SIXTEENTH WEEK. Cut in the median line through the neck 
 and mouth openings and study the side of the head. 
 
 GROUP V. Development of the honeybee. Needed: Two dozen 
 three-dram vials. Two watch glasses. Two large cover glasses. A 
 comb of brood in all stages. 
 
 TWELFTH WEEK. Examine carefully the heads and determine 
 by their size the number of stages represented. Take a number of 
 each, including the eggs and full-grown bees, and place each stage by 
 itself in vials of 50 % alcohol, and after two hours change to strong alco- 
 hol. Fix another set by first treating in hot water, as directed under 
 the second group, and puncturing in several places before putting into 
 alcohol. 
 
 THIRTEENTH WEEK. Study the three youngest stages of both 
 sets, studying them in alcohol in the watch glasses. Be careful that 
 the upper side of the cover glass remains dry. Describe the stages 
 and the changes undergone. 
 
 FOURTEENTH WEEK. Study the remaining stages to where the 
 wing cases appear. 
 
 FIFTEENTH WEEK. Study the stages bearing wing cases. 
 
 SIXTEENTH WEEK. Study the change to the adult condition. 
 
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