A Guide for the Study of Animals

by Worrallo Whitney; Frederic Colby Lucas; Harold Brough Shinn; Mabel Elizabeth Smallwood

CHAPTER VIII

[Poultry] 182

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[Glossary] 189

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A Guide for the Study of Animals

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CHAPTER I
INTRODUCTORY STUDIES OF LIVING ANIMALS

In the following brief exercises the primary purpose is to arouse an active, attentive interest on the part of the pupil in various forms of animal life which may be at hand, reminding him of what and how various creatures eat, how they breathe, how they get ideas of the world, how they get about, and perhaps how they succeed where others fail. Of secondary importance is the introduction of laboratory methods by easy stages. The pupil should feel that his natural curiosity is only being directed to definite ends and that he is free to investigate in his own way.

The types here given are only a few of the many to be found in the early fall, and these exercises in several cases may be used for other forms than those definitely mentioned. There should be a great deal of promiscuous collecting by the class, and in the mass of material gathered the following types will probably be fairly abundant.

THE LIVING FLY

Materials.

Living flies in cages and individual specimens in small wide-mouth vials with cotton stoppers for the admission of air. Sugar crystals may be used for feeding. Simple lenses.

Observations.

Notice the division of the body into three regions: head, thorax, and abdomen. The six legs, the large wings, and the small feelers may be easily found, as are the large eyes, the extensible mouth, and beneath the larger wings the small undeveloped ones looking like tiny knobs.

1. State the general color of your specimen and give any special markings on its body.
2. Is the body smooth or has it a covering of any kind? Do you regard the fly as a cleanly animal? Why?
3. Under what conditions does the fly use its legs? its wings? What enables it to walk upside down? What use can you assign to the small wings?
4. Judging by the relative size of the feelers and the eyes, do you think the fly relies more upon its sight or its feeling? Since the eyes can probably see you any place where you see them, determine through how much of a circle the fly can see.
5. How does the fly eat? Does it eat solid or liquid food?
6. Where is the extensible mouth (proboscis) kept when not in use? What is the fly doing when "washing its face"?
7. From your own observation in the barn and the alley what do you know about the fly's cleanliness in choosing its food? How would it affect articles in the pantry?
8. From the foregoing statements show how flies may be a serious factor in dealing with disease.
9. What means may be employed as protection against adult flies? against their breeding places and "maggots"?

Suggested drawing.

1. The entire fly, seen from above, × 4.

THE LIVING MAGGOT

Materials.

Living specimens in pans or cotton-stoppered bottles, with some food material and moist cloth or paper; lenses.

Observations.

Notice the general worm-like form of the maggot, or grub, the plain and uniform color, and the absence of all elaborate structures, as wings and feelers.

1. Since this creature is destined to become a flying or walking insect, what organs will have to appear? Is there any indication of these structures at present?
2. Give the color of the specimen, and explain how the presence or absence of strong light seems to have affected the color. Is this effect usual in animals or plants that you know?
3. Tell how the animal gets from place to place, describing any special structures you find which aid in this work.
4. How can you tell the head end? Tell how the amount of work that the mouth and mouth parts do affects their size and indirectly that of the region where they are.
5. What senses and sense organs has the maggot? Test any of these senses or organs gently, by any means at your disposal, or recall any experience you have had along this line. Which senses or organs seem to be best developed?
6. Explain briefly how the active or sluggish habits either determine or are determined by the condition of the senses or sense organs.
7. Since "Mother Nature" seems to want maggots to develop rapidly, tell how she economizes in energy and material when forming them.
8. Show how the development of maggots in refuse matter is actually beneficial.
9. From the standpoint of flies and human welfare, show why maggots should not be allowed to live,—stating how they may be prevented.
10. Look up the story of the pupa of the house fly; the development and work of the botfly; of the ox-warble; of the tsetse fly.

Suggested drawing.

1. The maggot or grub, side view, × 4.

THE LIVING COCKROACH

Materials.

Individual specimens in cages, jars, or wide-mouth vials with cotton stoppers to admit air. Several roaches in large cages with material for food and concealment.

Observations.

1. What is the general color and the average size of cockroaches?
2. During what time of the day are roaches most active? Where do they hide at other times? How do their shape and color aid concealment? Note any odd or striking colors or marks which might make them distinguishable to their mates.
3. Is the roach a quick or a slow moving animal? How does it get about,—by running, jumping, walking, crawling, swimming, or flying? Turn your specimen on its back and see how it recovers its proper position. Notice the relative size and development of the wings and their use in flying.
4. If uninjured, your specimen has six legs. Why don't they step on each other? Notice the stiff hairs on the legs and the white pads under the feet. How would these structures be useful to the animal?
5. The large, black, shiny eyes are on the front and sides of the head; the long "horns," or feelers, are attached just below the eyes. Upon which sense, sight or feeling, do you think the roach depends more? Explain your statement.
6. Beside the mouth are a long and a short pair of "feelers"; perhaps these are for tasting or smelling. What do roaches like to eat? Do they choose their food? What damage do they do?
7. How can a house be rid of cockroaches?

Suggested drawing.

1. [a. ]A cockroach, seen from above.

THE LIVING SPIDER

Materials.

Living spiders, preferably large ones, in cages; individual specimens in battery jars or wide-mouth bottles. Cocoons. Simple lenses.

Observations.

Each pupil may feel sure that if treated fairly any of the common spiders may be handled without fear of bite or injury.

1. Note that the spider's body is of two regions, the head-thorax and the abdomen, and that it is supported by eight legs. To what part of the body are the legs attached?
2. Find the feelers; if they are club-shaped, your specimen is a male. State their number and tell where they are attached. What is the sex of your spider?
3. Usually there are eight tiny near-sighted eyes on the front of the head. State the color of the eyes and by a diagram indicate their arrangement.
4. With what kind of material is the body covered (use the lens)?
5. What is the color of your specimen? What special markings has it?
6. Holding the spider aloft in your fingers, allow it to drop upon the thread it will spin, and watch it climb and spin. Record the number of the spinners, their situation, and how they act. Are the threads sticky? If so, why doesn't the spider stick to its web? Is the web used for a home or for a snare?
7. Try to discover how the feet are enabled to cling to the thread.
8. Examine a cocoon, noting its outer form and structure, and look for an opening at the top. If you can open a cocoon carefully with scissors, look for its two coats and inspect its contents.
9. State three uses for the spider's silk.
10. What is the work of spiders amongst the animal population of the earth, or of what use are they?
11. Out of doors find webs of various kinds: wheel web, tent web, triangle web, etc.
12. How do the jumping spiders differ from others in their spinning and feeding habits?
13. Look up what is meant by ballooning spiders. Find out when ballooning occurs and what is accomplished by it.

Find out the name of your kind of spider.

Suggested drawings.

1. The entire spider, seen from above.
2. A cocoon.

THE LIVING CRICKET

Materials.

Living crickets in cages, with materials for food and concealment, and individual specimens in wide-mouth bottles or vials with cotton stoppers.

Observations.

1. What is the average size and the general color of crickets?
2. Just what do they do when you try to catch them? What structures enable them to do these things?
3. Of the three pairs of legs, which extend sidewise for running or grasping, and which backward for jumping or climbing? What structures have the legs to enable them to do their work properly?
4. Notice how well developed the cricket's wings are, and state how much they are used or how they influence the habits of the animal.
5. How many projecting spines are there on the hinder end of the body? Are they ornamental or useful? how? The female crickets have a special spear-shaped spine for depositing eggs.
6. In a column make a list of the senses (sight, feeling, etc.), and opposite each state what kind of an organ is used and where it is located. The ears are oblong white spots on the second long piece of the front legs.
7. Find out whether the cricket chews solid food or sucks liquid food, and whether it has biting jaws or protrusible lips. See whether it will attack a toothpick or your finger, and if the crickets have been confined long, whether there has been any attempt at cannabalism. Is its natural food animal or vegetable matter?
8. How do crickets chirp?
9. What work do they do in nature?
10. How does a baby cricket develop?

THE LIVING GRASSHOPPER OR LOCUST

Materials.

Individual specimens in wide-mouth bottles or jars, and other specimens in cages, with turf or foliage for food and concealment. Simple lenses.

Observations.

Notice the form and size of your specimen, its color, the number of its legs and of its feelers. Find the eyes; the two large eyes, a tiny one between the two feelers, and near the inner edge of each large eye, another tiny one. With a lens notice the markings on the large eyes. Find the mouth, and note its lips and finger-like feelers. Draw out an outer wing, and then carefully draw out the delicate under wing, allowing them both to fold into place again. Under the wings find the circular or crescent-shaped membranes, the eardrums. Watch the grasshopper's body expand and contract in breathing, and find the small breathing holes along each side the body. Compare its rate of breathing with your own.

Questions.

1. In what surroundings and how does the grasshopper's color protect it? What color markings has it which might serve for other grasshoppers to see as signals? Explain how this signaling is done.
2. Explain how the legs are placed so as to act as springs in jumping and alighting.
3. What advantages in having the wings attached on the upper side and the legs on the under side of the body?
4. Explain how the small wings are protective, and how the large ones are protected.
5. Why is it better for the grasshopper to have its mouth on the under side of its head instead of in front?
6. The large eyes are supposed to be far-sighted, the small ones near-sighted. State how the large eyes have the more advantageous position, and around how much of a circle they can see.
7. Describe how the grasshopper breathes.

THE LIVING BUTTERFLY OR MOTH

Materials.

Individual specimens in large jars or cages, and other specimens in cages with foliage; simple lenses and a needle or pin.

Observations.

Butterflies may generally be distinguished from moths by their habit of holding their wings together above them when at rest, by the feelers which are knobbed at the end, and by the rather slender abdomen. Moths generally either fold their wings or hold them outstretched, their feelers are not knobbed, and their bodies are rather bulky.

Observe these points in your specimen and the colors of the upper and under sides of the wings. Find the large eyes and examine them with a lens. With the needle or pin carefully uncoil the sucking tube which you may find under the head between two shields. Note the fuzziness of the body and the "dust" which covers the wings. Examine some of this dust under a lens.

Questions.

1. Is your specimen a butterfly or a moth? Prove your statement. If possible, give the name of your specimen.
2. Write a description of your specimen—its size, general color, and special color pattern.
3. Describe the sucking tube, or "proboscis," and name some flowers from which it might obtain nectar. Try to find out how the tube is operated.
4. Why is it that moths and butterflies never bite? Do they sting? How do you think they protect themselves from enemies?
5. State how the fuzz and dust on your specimen might influence a bird's liking for it.
6. Contrast the size and usefulness of the wings of the butterfly with those of some other insect you know about; contrast their legs; state how development of one set of structures may cause another set to be simple or feeble.
7. Most moths are active by night. What explanation can you give for their large eyes and expanded feelers? Feelers of insects may be for any or all of the following: touch, taste, smell, and hearing.

Suggested drawings.

1. The butterfly or moth.
2. An antenna (feeler).

THE LIVING CATERPILLAR

Materials.

Living caterpillars in cages or covered jars for individual study, and other specimens in cages with foliage for food or concealment.

Observations.

The pupil should observe the general form and external construction of the caterpillar, watching it feeding, in action, and at rest.

Notice how the creature moves. Find its head, its segments (similar divisions of the body), and its breathing holes along the sides of the body. Try to find its eyes, any feelers, wings or paddles. Try to loosen it from its support; find the tiny hooks on the feet for clinging fast.

Questions.

1. Give the general color of your specimen and explain how this color may make it conspicuous or may aid its concealment.
2. Describe the outer surface or covering of the caterpillar. What structures, if any, are there, which might make the animal distasteful or inedible?
3. How many pairs of legs are there? How are they distributed along the body? Counting the segments, state which ones bear no legs.
4. To what extent do the legs act in locomotion? Are they mere organs for attachment while the body swings forward and backward, or do the legs do this, as in a horse? Make a complete statement.
5. Notice the openings of the internal breathing tubes. How are they protected against dust and other foreign matter?
6. Does the caterpillar seem to be a warm-blooded animal? State how the free access of air along the body would influence internal temperature.
7. What do you know about a caterpillar's appetite? How might caterpillars be beneficial or harmful? What means has nature of holding their numbers in check?
8. Recalling that caterpillars finally "sleep" for several days or weeks and awaken as winged creatures, how can you account for their appetites?

THE TUSSOCK MOTH

Materials.

Directions for the study of the caterpillar stage will be found in the exercise "The Living Caterpillar," and directions for the study of the adult male form will be found in the exercise "The Living Butterfly or Moth." The female tussock moth is a wingless, thick-bodied creature, gray in color, very downy, and about three fourths of an inch long. The following directions apply more particularly to the study of the cocoons and the general harmfulness of the tussock moth.

This exercise may be done best outside of the classroom, the pupil answering the questions on scrap paper and rewriting these notes in the laboratory. Living caterpillars, cocoons, some of them bearing their frothy masses of wax and eggs, pupæ, and adult moths of both sexes may be used in the laboratory.

Observations and Questions.

1. On what kinds of trees are the cocoons and the caterpillars generally found? What effect have the caterpillars on the trees, and what may possibly be the final effect upon the trees of the locality or the entire district?
2. Upon what part of the tree are the cocoons made, and why? Where on the bark are they, and why?
3. Is the opening of the cocoon at the upper or the lower end? What reason can you assign for this?
4. Count the number of cocoons upon the entire tree or estimate it by counting those upon a part of the tree. Now count the number of eggs on a cocoon. Assuming that one half of the cocoons bear eggs, calculate the number of caterpillars on a tree next year.
5. How is the waxy covering of the eggs a particularly good protection against winter weather?
6. Investigate the interiors of several cocoons and state what you find.
7. On the pupa find the jointed and tapering hinder end, abdomen, and at the head region and lying along the under side, the marks of the legs and the feelers, and possibly the wings, all pressed close against the body. Find also the breathing pores along the sides of the abdomen.
8. Unlikeness between male and female is called "sexual dimorphism." Explain how the tussock moth shows this. For what work does each form seem particularly adapted?
9. What methods would you use that the tussock moth might be destroyed or kept out of a community?

The numerous small worm-like creatures often found are the caterpillar stages of another insect, an ichneumon fly, which laid its eggs under the skin of the tussock caterpillar. How has their development affected that of the tussock moth? What great result does nature accomplish by this arrangement?

Suggested drawings.

1. A caterpillar, × 2.
2. A cocoon with its egg mass.
3. A pupa as seen from the under side.
4. An adult moth, either male or female.

THE LIVING BEETLE

Materials.

Living beetles in cages, together with portions of the plant upon which they are found; or if water beetles are used, they should be kept in aquaria. Individual specimens in battery jars or wide-mouth bottles, and preserved beetles in pans or vials for reference.

Observations.

1. Upon what plant or in what surroundings is your kind of beetle generally found? If you can, give its common name.
2. What is the length, breadth, and thickness of your beetle? Would you describe it as a "small" insect or a "large" one?
3. Of what general color is it? Describe any color markings you see.
4. If any of the legs differ from the others or are of peculiar shape or length, describe them and tell what you think they may be fitted to do.
5. As a rule, beetles have harder "shells" than other insects. Does this shell completely inclose the body, or can you find any soft parts exposed? How are the head, thorax, and abdomen joined so as to carry out the apparent purpose of protection? What is the outline of the body—a continuous line or one with many irregularities?
6. If possible, try to lift up one side of the "shell" from the hinder end of the body. You will discover that this portion of the shell is a pair of hard sheath wings, and beneath them is another pair. How are the under ones unlike the upper in size and texture? in use? in arrangement when not in use?
7. Does a beetle spend most of its life on the wing, like bees and flies? How might the body covering and the structure of the outer wings affect or determine the beetle's habits, even against its will?
8. Are the feelers or are the eyes of your specimen more easily distinguished? Upon which of the special senses does it seem to place most dependence?
9. Is your kind of beetle good for anything, either in nature or in human affairs? Make a statement regarding what good or what harm it may do.

THE DAMSEL FLY LARVA

Materials.

Living larvæ of the damsel fly in shallow watch glasses of water for individual use, and others in large pans or aquaria. Simple lenses or dissecting microscopes.

Observations.

1. What is the color and the shape of the larva? how long is it? Notice in what surroundings in the water the larva lives, and answer to yourself how its form and color would protect it in those surroundings.
2. Since the larva is an insect, though immature, its body is composed of three regions: head, thorax, and abdomen. How do these regions differ from each other?
3. What structures has your specimen to enable it to move from place to place? If fully developed wings are not present, what indication is there of their being formed?
4. What sense organs has the larva? Which ones seem to be the largest and most useful?
5. Although the aquatic larva is preparing for adult life in the air, there should be some arrangement for securing air in the water. Where do you find outgrowths of the skin which might increase the air-absorbing surface? How many of these structures are there? Look within them for the air tubes,—fine branching black lines.
6. If possible, without injury to the specimen, examine the larva's mouth. Try to discover how it is used and how it is protected when not in use.

Suggested drawings.

1. The entire larva, × 4.
2. A gill, as seen through the microscope.
3. The feeding apparatus, × 10.

PLANT LICE AND SCALE BUGS

Plant Lice (Aphids)

Materials.

Plant lice on various kinds of plants, such as house plants, golden glow, and other plants from the garden or field. Garden asters with root lice (the asters should be transplanted into pots).

Observations.

1. Describe the size, appearance, and colors of the plant lice in your collection and their relation to the host plant.
2. Are the lice active or sluggish? (Compare with a house fly, for instance.) What proportion of them have wings? What is the usual method of locomotion?
3. Examining a single winged specimen, how many wings do you find? How do they fold? What is the character of the wings?
4. What is the food of the plant lice? How is the food obtained? (With a hand lens identify the piercing organ.) On what parts of the plants are they found? Does the plant show any indication of being harmed by the lice? If so, how?
5. Make a count of the plant lice upon a portion of a plant and estimate the whole number upon a plant. Why are plant lice a very serious pest?
6. If any plant lice have ants associated with them, study the behavior of the ants in this curious relationship. What advantages result from this relationship of ant and aphis to either or both insects?

Scale Bugs

Materials.

Twigs of trees, leaves, fruit, ferns, etc., infested with these bugs. If possible, have samples of San José scales, maple scales, and oyster scales.

Observations.

1. What is the general size and appearance of the various scale bugs in your collection? How do they differ in form and size and color?
2. Remove a scale and study it carefully with a lens. What is under the scale? Of what is the scale composed? What do you discover about these bugs to indicate that they are really insects?
3. What can be said about the number of scale bugs? Why are they difficult to exterminate? How can they be distributed from one place to another, as from orchard to orchard, since only the males have wings?

Drawings suggested.

1. A single aphis as seen with hand lens.
2. Various scale bugs as seen with a hand lens.
3. Twigs showing the distribution and numbers of scale bugs.

WATER BUGS AND BEETLES

Water Bugs

Materials.

Water bugs and beetles of several species in small aquaria covered with a wire net.

Observations.

1. With what legs does the bug swim? Describe their appearance and tell how used and how fitted for this use. Which legs are not used in swimming?
2. Remove the bug from the water for a moment to test other methods of locomotion, as jumping, crawling, flying. What do you discover?
3. Watch the bug as it gets a fresh supply of air, and describe the process. Where is the air stored for use when under water? Does the bug sink or rise when it stops swimming? Why?
4. Identify the bug's mouth parts. What is their appearance and probable manner of use? How are the forelegs fitted for grasping food?
5. What is the shape of the body? What is the position of the wings? Do the two cover (fore) wings meet in a straight line or do they cross at their tips? Are they smooth throughout and sheath-like, or are they thick at the base and thin at the tips?

Summary.

Summarize your study of the bug by enumerating the various ways the bug is adapted for life in the water.

Water Beetles

Use the same questions for the study of water beetles as for water bugs. In addition answer the following:—

1. Identify the eyes of the whirligig beetle and note their peculiar construction. How can you explain this peculiar form of the eyes on the basis of use? Why are the antennæ of both water bugs and beetles so small?

Suggested drawings.

1. The dorsal view of both bug and beetle.
2. Ventral view of the bug's head to show the beak and first pair of legs.

GETTING ACQUAINTED WITH THE LIBRARY

Directions.

The books in a zoölogical library may be roughly divided into three groups:—

1. Reference books.
   1. Advanced textbooks.
   2. Elementary textbooks.
   3. Natural histories.
   4. Books for classifying or naming animals.
2. Descriptive books.
   1. Life histories and habits of animals.
   2. Adventures with animals—popular accounts of animals seen on walks and travels.
3. Economic zoölogy.
   1. Books on harmful animals and methods of destroying them.
   2. Books on useful nondomesticated animals and their products.
   3. Books on domestic animals.
   4. Books of a general nature not included in the above.

Examine as many of the books in your library as you can and record for each one in your notebook:—

1. Title of the book; author's name; publisher; date of publication.
2. The kind of book as classified above.
3. What it includes or what animals or topics are covered by the book.
4. Whether the style is popular or technical, i.e. whether it is easy for you to read.
5. The general character of its illustrations and whether they appear to be especially helpful.
6. Comments on the value or interest of the book as it appears to you.
7. Select a book which interests you, for future reading.

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CHAPTER II
STUDIES OF INSECTS

The effect of great numbers upon the structure and habits of animals. The use of keys in finding the names of animals.

1. FIELD STUDIES

Materials.

1. Boxes for carrying insects. 2. A net. This may be homemade, using mosquito netting or fish net and a stout wire. If it is to be used for a dragnet for water insects, the wire must be stout and the netting strong. Make the net twice as long as wide. 3. A cyanide jar for killing insects. 4. A few paper triangles for carrying butterflies. 5. A notebook.

Note.—Your instructor will give directions for obtaining the material called for in 3, 4, and 5.

Directions.

Look carefully and quietly in the various situations noted below. Do not be in a hurry. Weedy meadows or vacant lots and neglected roadsides are good places for your first trips. Note concerning each insect found: (a) its name or something by which to identify it, (b) where you found it, (c) what it was doing, (d) its probable food. Record these observations in your notebook. Make a special study of such insects as your instructor may designate.

Where to look for Various Insects

Grasshoppers, locusts, katydids. Look along roadsides, waste places, gardens, especially weedy ones, weedy lots, and grassy meadows and pastures. Crickets. Under old boards, along the edges of board or stone walks, along fences. Beetles. Same locations as for crickets, and also on flowering plants, under loose bark of trees and stumps, in rotten logs, etc. For water beetles drag edges of ponds and streams. Dragon flies. Along water-courses, ponds, and swamps. Drag ponds and ditches for larvæ. Bees. On flowering plants, especially on large patches of wild asters, golden-rods, and thistles. Wasps. Sandy stretches,—especially along the water,—among flowering plants, under the eaves and roofs of outbuildings. Nests may be found in these latter places. Butterflies and moths. In fields where there are many flowering plants; look carefully on the leaves of plants for caterpillars, and for eggs. Also look very carefully on the under side of leaves, on twigs, and on the bark of trees for chrysalids of butterflies and cocoons of moths. Bugs. In same locations as for bees and grasshoppers and water beetles. Also on fruit. Aphids. On the fresh growing tops of plants. Tree hoppers. On trees and shrubs. Hold your net on the under side of branches and shake the branch vigorously. Flies. Around decaying substances, as garbage, fruit, etc.; on flowering plants. Ants. Sandy waste places, decayed logs, along walks, often in kitchens.

Note.—At night many kinds of insects fly around electric lights or into open windows, attracted by the light and may easily be collected.

Form for Field Trip Report

The notes taken on a field trip may be conveniently tabulated for permanent record in the form indicated below:—

Field Trip Report
Date________ Time________ Locality________ Pupil's Name________

Name of Insect	Where Found	What it was Doing	Probable Food

In case the name of the insect is not known to you, use a number and some designation as to color or other mark by which it may be known until you have leisure to look up its name by means of keys or books on insects.

Special Field Studies

The questions below may be used for a more careful field study of any insect.

1. Just where was the insect found?
2. Note carefully what the insects are doing before they are disturbed by your presence. What did the insects do when you disturbed them? If you think this related to securing safety, explain what leads you to think so.
3. What senses do you conclude are well developed? Reason for your conclusion.
4. Has the insect a home? If so, what is its character?
5. What is the color? What is the relation between the color of the insect and its surroundings?
6. Is the insect solitary in its habits or associated with others of the same species? If in association with others, note the numbers, and what they are doing.
7. What modes of locomotion do you observe in this insect? Which is the most common? If it flies or jumps, note the distance.
8. If you find the young, note whether they differ from the adult in general appearance, and if so, in what ways they differ. Do they differ in food?
9. What other insects do you find in the same habitat?

2. A STUDY OF GRASSHOPPERS (LOCUSTS)

Insects adapted to Life in Grassy Meadows and Fields

Materials.

Both living and dead specimens of grasshoppers. Various stages of young grasshoppers either dead or living. Some mounted specimens with wings spread. The wings of grasshoppers mounted in pairs between two glass slides for use with microscope or hand lens. Mounted preparations of mouth parts and tracheæ.

Definitions.

Orthoptera, straight-winged insects, order to which belong grasshoppers, locusts, katydids, crickets, cockroaches, etc. Vivarium, a cage in which living animals are kept. Anterior, toward the head of an animal. Posterior, opposite to anterior. Dorsal, the upper surface of an animal. Ventral, opposite to dorsal. Regions, principal divisions of the body of an animal. Head, thorax, and abdomen, the three distinct regions into which the body of a grasshopper is divided. Somite, a ring-like division of the body of an animal. Prothorax, mesothorax, and metathorax, the three divisions or somites into which the thorax of any insect is divided. A pair of legs is borne on each division. Exoskeleton, an external skeleton. Femur, tibia, and tarsus, the three principal divisions of the leg corresponding to thigh, shank, and foot. Veins, thread-like thickenings of the wings. Ocelli, the single or simple eyes of an insect, composed of a single eye element. Compound eyes, made up of many eye elements. Auditory sacs, organs for hearing in many animals. Antennæ, the feelers borne on the head. Labrum, the upper lip. Labium, the lower lip, formed by the growing together of the second maxillæ. Mandibles, primary jaws situated under the labrum. Maxillæ, secondary jaws just in front of the labium, each composed of three parts, a palp, a spoon, and a tooth. Palps, the jointed finger-like structures used to handle food, one pair on the labium and one pair on the maxillæ. Spiracles, openings into the trachea found along the sides of the abdomen and thorax. Tracheæ, slender tubes used for breathing organs among insects. They carry the air direct to the tissues in all parts of the body. Ovipositors, structures on the posterior end of the abdomen of a female, used to deposit eggs. Metamorphosis, refers to the development of the young of animals when striking changes in structure occur in the course of their growth. Metamorphosis is called complete when the young have no resemblance to the adults, and incomplete when there is a resemblance to the adult. In complete metamorphosis the stages are larva, pupa, and adult. In incomplete metamorphosis the stages are nymph and adult.

Observations.

The Body.

1. Show how the shape of the grasshopper's body is well adapted to its needs.
2. Which region of the body is the thickest? What seems to be the reason for this? Which regions are capable of movement?

1. What are the various kinds of locomotion a grasshopper can use? Which are used in the vivarium and which when free in the laboratory?
2. Which legs are used in jumping? How are these legs especially adapted to this, in length, structure and direction? Could a grasshopper jump if the third pair of legs were arranged like the other two pairs? Why?
3. How is the animal able to cling to grass stems and not slip down? What is the direction of the body in relation to the stem or grass blade?
4. What is the position of the wings when at rest? when in use? How do the hind wings fold? How are the principal veins of the wings arranged to permit or facilitate this folding?
5. Contrast the fore and hind wings with respect to thickness, size, and use.
6. To which somites of the thorax are the wings attached? Nearer which surface, the dorsal or ventral? Why?

1. Discover all you can about the uses of the antennæ by carefully observing grasshoppers at rest, feeding, jumping and crawling, approaching an object or another grasshopper, etc.
2. How many compound eyes has the grasshopper? How many simple eyes? Where are they located?
3. Examine a preparation of the compound eye with the low power or as demonstrated with the stereopticon. What is the shape of an eye element of the compound eye? About how many eye elements are there in a compound eye?

1. Do grasshoppers eat and drink while in captivity? Put a fresh bunch of grass which has been sprinkled with water in a vivarium with grasshoppers that have had no food or drink for twenty-four hours and watch results.
2. What is the position of the grasshoppers in feeding? In what direction do the jaws move in feeding? Compare this with the direction of movement of your own jaws. What is the use of the palps? What do you think is the use of the "molasses" or saliva that flows from the mouth?

1. Describe the breathing movements of a grasshopper and explain the relation of the movements to inhalation and exhalation of air.
2. Find the exact location and number of spiracles on the abdomen. There are two pairs of spiracles on the thorax. Find them. How do the spiracles prevent the entrance of dust?
3. Describe a trachea as seen in a mounted preparation with the aid of a microscope or stereopticon.

1. Explain how the colors of the grasshopper may be protective or useful when at rest in its natural habitat and when in flight.
2. Does the shell cover the entire body? What are the advantages of such a covering? A shell is likely to hinder activity, sensitiveness, and growth. How are such disadvantages overcome in this case?
3. What senses are probably most relied upon to detect approaching danger? Give evidence to support your answer.
4. What is the position of the hind legs when at rest? What relation has this to safety?

1. Describe the ovipositors and the probable method of their use. Describe the egg packets of grasshoppers, if discovered. About how many eggs in one? (They are sometimes seen against the glass sides of the vivaria.)
2. If you have young grasshoppers of various ages, arrange a set of them in what seems to you to be the order of their development. How do young grasshoppers differ from adults? What changes take place as they develop? What kind of metamorphosis is this?

Summary of Important Points in the Study of the Grasshopper

1. How many and what distinct regions of the body are there?
2. How many antennæ? Compare their length with that of the body. What other sense organs did you discover?
3. How many legs? For what specially adapted? How?
4. How many wings? What is their resting position? How do the fore wings differ from the hind wings? How do the hind wings fold?
5. To what kind of feeding are they adapted, biting or sucking the food? How many and what sets of mouth parts are there?
6. How is air necessary for respiration obtained?
7. In what various ways are grasshoppers fitted for life in meadows and weed plots?
8. How do they meet winter conditions?
9. What kind of metamorphosis has the grasshopper?

Drawings suggested.

1. Side view with the legs and wings removed. Label all parts shown in this drawing. (See [Definitions] on pages 23 and 24 for names of parts.)
2. Face view of the head, showing the simple and compound eyes, the antennæ, labrum, and palps.
3. One of the third pair of legs. Label parts.
4. A fore and a hind wing arranged in natural position.
5. A young grasshopper.

3. COMPARATIVE STUDY OF ORTHOPTERA

Materials.

Mounted specimens of various common species of orthoptera.

Observations.

1. Where does the insect live? What is its color?
2. What is the size and shape as compared with the grasshopper?
3. What is the length of the antennæ as compared with the length of the body?
4. To what kind of locomotion are the legs adapted? How? Are the forelegs specially adapted for grasping?
5. What is the position of the wings when at rest? Are they large or small as compared with the size of the body?
6. Are the ovipositors long or short? (Compare with those of the grasshopper.)
7. Find the group to which the insect belongs and its name by the key in the following section.

4. KEY TO SOME COMMON ORTHOPTERA

A. Groups

Legs	Antennæ	Other Characters	Groups
Similar, fitted for running	Long	Body flattened, wings folded on dorsal surface of the abdomen	Cockroaches (Blattidæ)
First pair of legs enlarged for grasping	Rather long	Prothorax long and slender, wings folded on dorsal surface of abdomen	Mantis (Mantidæ)
Similar, fitted for walking	Long	Body usually greatly elongated and stick-like, usually no wings	Walking stick (Phasmidæ)
Hind legs fitted for jumping	Short	Body somewhat compressed, wings folded on side of abdomen	Short-horned grasshoppers (Acrididæ)
	Long	Body compressed, wings folded on sides, tarsus four-jointed	Long-horned grasshoppers (Locustidæ)
	Long	Body somewhat flattened, wings folded on the back, tarsus three-jointed	Crickets (Gryllidæ)

B. Species or Genera

Characters of Species	Common Name	Groups
Large size, brown color	American cockroach	Cockroaches
Small size, pale brown	"Croton bug"
Dark color, often wingless	Oriental cockroach
Body long, anterior portion slender	Mantis or rear horse	Mantis
Long body, long legs, no wings	Walking stick	Walking sticks
Very large size, wings very small	Lubber grasshopper	Short-horned grasshoppers
Small to medium size, legs marked with red	Red-legged grasshopper
Large size, greenish brown color	Differential locust
Medium to large size, sand color (gray)	Carolina locusts
Rather large, green, wings large and angled	Angle-wing katydid	Long-horned grasshoppers
Small to rather large, usually green	Meadow grasshopper
Wingless, brown color	Cricket grasshopper
Usually rather large, black	Field cricket	Crickets
Wingless, front legs shovel-shaped	Mole cricket

5. THE DRAGON FLY

An Insect adapted to Aerial Life

Materials.

Mounted specimens of dragon flies, some moist preserved specimens, living specimens if practicable, simple lenses.

Observations.

1. Identify the three regions of the body and note the presence of a distinct neck. What is the length of the insect? What is its general form? If you have living specimens, discover what movements the head and abdomen are capable of making.
2. What is the position and general character of the wings? Explain how these wings are made very efficient for flying. Why should they not fold?
3. For what do the legs seem best adapted? Why?
4. Note the size of the eyes and of the antennæ? How do you account for the great size of the eyes and the relatively small antennæ?
5. What is the type of mouth parts, biting or sucking? If you have living dragon flies, try feeding them flies or mosquitoes and note how they are seized.
6. The food of dragon flies is mosquitoes and flies caught while on the wing. In what various ways is the dragon fly specialized for getting food in this manner?

Summary.

How is the dragon fly fitted for its aerial life with respect to its body, means and method of locomotion, sense organs, kind of food and manner of obtaining it?

Suggested drawing.

1. Dorsal view, showing veining of one wing.

6. THE HONEYBEE

A Study of Adaptations for Community Life

Materials.

Preserved specimens of workers in small vials and in watch glasses, and some mounted specimens. A demonstration case showing the three kinds of members of the community, stages in the development of the workers and queens and the cells in which they are reared, specimens of the comb. Small pieces of beeswax, a box of honey, and specimens of comb free for examination. Mounted preparations of mouth parts and stings. Simple lenses and compound microscopes.

Observations.

The Worker Bee.

1. Observe and describe the form, size, regions, and covering of the bee. What are its colors?
2. Observe and describe the texture, veining, relative size, and position of the wings. Discover how the fore and hind wings are hooked together. What advantage in having them hooked together?
3. For what kind of locomotion are the legs best adapted?
4. Find the pollen basket on the tarsus of a hind leg. How is it fitted for carrying pollen? What are the wax shears?
   1. Examine and describe the structure at the posterior end of the body used for stinging. (Use a mounted preparation for this with low-power of microscope.)
   2. The mouth parts are fitted for both biting and sucking. Find what makes this possible. (Use mounted preparation.)
5. Describe the antennæ and the number, position, and shape of the eyes. Are the eyes fitted for keen sight? Give reason for answer.
6. The worker bee gathers honey and pollen and defends the entire community from enemies. What various adaptations fit it for this work?

1. How do the workers, drones, and queen differ in general appearance?
2. Describe the appearance of the comb and the arrangement and shape of the cells. Why this shape? How are the cells closed when full of honey?
3. How do the cells used for rearing worker bees differ from those used for rearing queens? What is the appearance of the larvæ? Of the pupa?
4. Examine and test in various ways a small piece of beeswax. What are the qualities possessed by this wax which make it suitable for making comb and protecting the home from storms?

Supplementary Studies of Bees

Materials.

For this study an observation hive of bees or opportunity to visit an apiary will be helpful. If neither are practicable, then look up the answers in books. There are government bulletins on bee-keeping and much helpful information can be obtained from large dealers in bees and bee supplies.

Observations.

1. How do bees protect their hives from rain and storm and light?
2. What are honey boxes? Where are they placed in the hive? Can the honey be removed late in the fall?
3. How is it safe to approach and handle bees in removing honey and caring for them?
4. What are their habits in entering and leaving the hive? What is the appearance of a returning loaded worker bee?
5. How do bees survive the winter? Why are the drones driven away or killed?
6. Watch bees gathering nectar and pollen from flowers and describe the process. Try following a bee on its journeys.
7. When the bees are in the hive, how may you know the queen and drones from the workers?
8. What is swarming? When does it take place? How is the swarm hived?
9. What is the home of wild honeybees? How found?

Summary of the Study of Honeybees

How is the work of the community of bees divided among the bees? How is each fitted for the work? What do you think of the success of this kind of life? Give reasons for your answer.

7. GENERAL STUDY OF INSECTS[1]

Materials.

Both living and preserved specimens of the insects studied should be at hand, if practicable. There also should be specimens of the young.

Observations.

The Body.

1. What is the shape and size of the insect and the number of regions in its body? Does the shape seem to be in any way adapted to the mode of life of the insect? If so, how?

1. What methods of locomotion has the insect? Which is the most used?
2. What is the position of the wings when at rest? What is the texture (e.g. thick, smooth, leathery, shell-like, membranous) of the fore and hind wings?
3. For what kind of locomotion are the legs fitted? How?

1. How many antennæ has the insect? What is their character as to shape and length? How many simple and compound eyes?

1. What is the food of the insect? How are the mouth parts specially adapted to obtaining this food?
2. Note.—The mouth parts of insects may be jaws for biting, or may form a tube for sucking, or a beak for piercing and sucking.

1. Look for movements of the body indicating breathing, and describe what you find. Discover the location of the spiracles.

1. What are the enemies of this insect? (Among the most important enemies of insects are birds, certain other insects, and various small vertebrates such as frogs, snakes, lizards, turtles, etc.) How does the insect protect itself from these enemies?
2. Describe the shell with respect to thickness and flexibility. What is the character of the surface as to roughness or smoothness or covering of hairs or scales?

1. Where are the eggs deposited? What is the number of the eggs? How soon do they hatch?
2. What is the food of the larva or nymph? Are the food habits of the insects harmful to man? If so, how?
3. Describe the larva as to form, color, and appendages. Is it capable of locomotion?
4. Is the metamorphosis complete or incomplete? If complete, describe the pupa and tell where it may be found.

Drawings.

There should be one drawing of the insect to show its general characteristics; usually a dorsal view is best. For other drawings ask your instructor.

8. A REVIEW OF INSECTS

Directions.

The answers to questions in this study may be conveniently written in the form of a table. Construct this table by placing the topics at the left and the names of insects at the top. Allow ample space, about one half inch for the horizontal spaces and one and one half inches in width for the vertical columns. Use one or two insects from each of the principal orders, letting the table extend across two opposite pages.

Topics.

1. What is the habitat?
2. What regions has the body?
3. How many antennæ? What is their form?
4. What kinds of eyes has the insect? How many of each kind?
5. How many legs?
6. For what kind of locomotion are the legs adapted? Which legs are thus used?
7. How many wings? Membranous or thickened?
8. What is the position of the wings when at rest?
9. If the fore wings are thickened, what is their texture,—leathery, smooth and sheath-like, partly membranous, covered with scales?
10. What kind of mouth parts,—jaws for biting, a beak for piercing, a tube for sucking, adapted for both sucking and biting?
11. By what means is respiration accomplished?

Summary of Important Points from the Table

1. What characters are common to all the insects described in the table?
2. What are the various types of wings? Why do they vary?
3. What are the various types of legs? How are they characterized?
4. What are the various types of mouth parts?
5. Show how the variations in insects are related to the habitat and mode of life of the insect.

9. KEY TO THE PRINCIPAL ORDERS OF INSECTS

A1	Insects with no wings. (See [list below].)
A2	Insects with wings	B
B1	With two pairs of wings. (See [Note 1] below.)	C
B2	With one pair of wings		Diptera
C1	Both pairs of wings alike in structure, either membranous or scaly	D
C2	Fore and hind wings unlike in texture, fore wingsfold over hind wings	E
D1	Both pairs of wings membranous, not covered withscales	F
D2	Both pairs of wings covered with scales; mouthparts tubular for sucking		Lepidoptera
E1	Fore wings very smooth, sheath or shell-like, meetingin a straight line when folded; legsadapted for walking, running, or swimming;mouth parts for biting		Coleoptera
E2	Wings not as in E1	I
F1	Wings membranous, usually folded or partlyfolded; few nerves	G
F2	Both pairs of membranous wings usually outspread,many nerves; mouth parts for biting	H
G1	Wings membranous, hooked together and partlyfolded, or outspread, few nerves in the wings;mouth parts for both biting and sucking; regionsof the body usually very distinct		Hymenoptera
G2	Wings membranous, usually folded, few nerves;mouth parts, a beak for sucking and piercing		Hemiptera
H1	Outspread membranous wings, nearly equal insize; antennæ very short and inconspicuous		Odonata
H2	As in F2, but antennæ not short; wings sometimesfolded		Neuroptera
H3	Both pairs of wings membranous, folded abovethe back; fore wings much larger than hindwings; ovipositors long; mouth parts rudimentary		Ephemerida
I1	Fore wings folded over hind wings, crossing attheir tips, which are membranous, base ofwings thickened, mouth parts a beak forpiercing		Hemiptera
I2	Fore wings leathery, folding either at side of bodyor on the back; mouth parts for biting, legsoften adapted for jumping		Orthoptera

Note 1.—When wings are folded, it will be helpful to remember that thickened fore or cover wings always have membranous wings folded beneath them.

	Insects with no wings	Order
a.	Body long and slender, stick-like; legs for walking. Walking stick	Orthoptera
b.	Grasshopper-like. Cricket grasshopper	Orthoptera
c.	Small size; regions very distinct; abdomen spindle-shape. Ants	Hymenoptera
d.	Small size; ant-like in appearance; pale white. White ants	Isoptera
e.	Flattened body, small size; no compound eyes. Springtails and fish moths	Thysanura

10. SUMMARY OF THE STUDIES OF INSECTS

The Effect of Great Numbers

1. Take some insect for illustration, as the house fly, mosquito, tussock moth, or aphis, and show how insects increase in numbers with great rapidity.
2. What can be said about the number of species of insects?
3. There is said to be great competition among insects. Why? For what?
4. How is the great increase of insects held in check by natural means?
5. What are the various habitats of insects? Give as many as you can with examples of insects that use the habitat.
6. Give examples to show how greatly the food of insects and the method of obtaining it varies.
7. Give some illustrations of the great muscular development of insects. Why is this needed?
8. In what various ways are insects protected against their enemies? Give examples to illustrate your statement.
9. Show how and why the great numbers of insects have affected the structure and mode of life of the insects.

Classification

1. By means of illustrations from your studies of insects show how classification is based upon likeness of structure.
2. In the same manner show how differences in structure affect classification.
3. Show how variation in the wings and mouth parts is used to separate insects into orders.
4. What are the principles of classification?

11. REVIEW AND LIBRARY EXERCISE ON INSECTS

General Topics

1. General characteristics of insects.
2. Principal orders of insects with characteristics and examples of each order.
3. Respiration and air sacs of insects. Use of air sacs in flight.
4. The heart and blood of insects. How the function of the blood differs from that of other animals, as man.
5. Special senses of insects: their character, location, and efficiency.
6. Sound-making organs of insects.
7. Power of communication among insects, as among ants, for example.
8. Organs for depositing eggs, ovipositors. How they vary.
9. Homes of insects. Evidences of architecture in some of the homes.
10. How some plants make homes for insects. Galls and gall insects.
11. In what various ways do insects survive the winter? Illustrate with examples.
12. Community life among insects. Types of communities.
13. Pollination of flowers by insects. Why insects do this work and how the flowers compel them to do it in the right manner. Value to the plants. Types of insects useful for this purpose.
14. Adaptations for protection against enemies. Classify these adaptations and illustrate with examples.
15. The principal insect pests of the orchard and their work.
16. The principal insect pests of the garden and the work of each.
17. The principal insect pests of shade trees and their characteristics.
18. The principal insect pests of the household and methods of extermination.
19. The work of birds in helping to keep the number of harmful insects down.
20. A spraying table showing what poisons are used, when and for what plants and insects.
21. The principal beneficial insects and the ways in which they are beneficial.

Special Topics

Much of the information called for by the topics below may be obtained from United States and state government bulletins. Most of these may be obtained free from the Department of Agriculture and from various state agricultural colleges, while others may be obtained by purchase at a nominal price.

Orthoptera.

1. Locust migrations and their cause.
2. The locust plagues of the "great plains."
3. Crickets and their "songs."

1. The fight against the orange scale of California.
2. History of the introduction and spread of the San José scale bug and the efforts to find a natural enemy. How people fight the pest.
3. Aphids.
4. Relations of ants and aphids.
5. Phylloxera and its work.
6. The methods of fighting the chinch bug.
7. Scale bugs.
8. Cochineal bug and the lacs.

1. The carrion beetle and its peculiar habits.
2. Fireflies.
3. Egyptian scarabs.
4. The curculio and methods of fighting it.
5. The weevils and their work.
6. History of the Colorado potato beetle.
7. Lady-bird beetles, their habits and use in exterminating harmful pests.

1. The investigations in Cuba of the cause of yellow fever.
2. The fight against yellow fever in New Orleans.
3. Methods of preventing plagues of mosquitoes.
4. How flies are carriers of disease. Methods of preventing plagues of flies.
5. The tsetse fly.
6. Sleeping sickness.
7. The house fly and typhoid.
8. Parasitic larvæ of flies.

1. The silkworm and the silk industry.
2. Story of the gypsy moth.
3. Life history of the clothes moth.
4. Harmful butterflies.
5. The tussock moth and its history.
6. Blastophaga and fig culture.
7. The codling moth and its work.
8. Cutworms.
9. The brown-tail moth.

1. The honeybee and honey making.
2. Gall and gall insects.
3. The habits of the digger wasp.
4. The homes of ants. Habits of ants.
5. Slavery among ants.
6. Agricultural ants.
7. Homes of bees.
8. Ichneumon flies and their beneficial habit.
9. Evidences of intelligence among ants.

SOME COMMON BUTTERFLIES—A Reference Table and Key

Group	Common Name	Wing Expanse in Inches	Broods	Food Plants of Caterpillar	Haunts of the Butterfly	Characteristic Colors, Markings, Etc.
Milkweed Butterflies	Monarch	4–4½	May and Oct.	Milkweed and dogbane	Open fields everywhere	Brick-red color, veins black, borders of wings black
Fritillaries or Silver Spots	Variegated fritillary	1¾–2½	August	Passion flower	Low fields	Orange-brown color, checkered with black, no silver spots. A southern species
	Regal fritillary	3–4	July, Aug.	Violets, pansies	Low fields	Upper side of wings reddish with wavy black lines, hind wing dark
	Great spangled fritillary	3–4	July, Aug.	Violets, pansies	Meadows	Similar to idalia, but hind wings lighter. Silver spots on under surface of wings
	Silver-bordered fritillary	1½	July, Aug., Sep.	Violets, pansies	Meadows, hillsides	Edge of wings tipped with silver, silver spots below
	Meadow fritillary	1¾	July, Aug., Sep.	Violets, pansies	Meadows	No silver border, silver below
Checker Spots	Baltimore	1¼–2¼	June, July	Turtlehead and aster	Swamps	Groundwork of black with many red and white spots. Conspicuous border of red spots
	Harris checker spot	1½	June	Aster and daisy	Clover meadows	Wings dark bordered, lighter band across middle of wings
Crescent Spots	Silver crescent	1¼–2	July	Asters	Roadsides	Groundwork of orange-red mottled with black, silver crescents on under margin of hind wings
	Pearl crescent	1¼–1⅝	July, Sep.	Asters, daisy	Roadsides	Similar to silver crescent but colors are paler
Angle wings	Comma	2	May, June, Aug.	Elm, nettle, hop	Along woods and waste places	Pale red, angled wings, under surface light gray marked with silver commas
	Interrogation	2½	May, July, Aug.	Elm, nettle, hop	Near trees	Similar to comma, but marked with silver semi-colons
Tortoise Shells	Compton's tortoise	2¾	Feb., Oct.	Willow	Near water	Looks much like the angle wings, but has no silver spots
	Milberts's tortoise	1¾	May, June, Aug., Sep.	Nettle	Roadsides	Broad, reddish yellow band across both wings
	Mourning cloak	3	Apr., July, Sep.	Willow, poplar	Everywhere	Black with yellow or cream-bordered wings
The Beauties	Red admiral	2	May, July, Sep.	Nettle, elm	Waste land	Bright red band circling across both wings
	Painted beauty	2	May, July, Sep.	Everlasting, thistle, burdock	Thistles	Mottled with pink, black and white, under surface mottled, two large spots on under surface of hind wing
	Thistle butterfly	2–2¼	May, July, Sep.	Thistles	Pastures	Like the painted beauty, but has several small eye spots
The White Admirals	Red-spotted purple	3	July	Wild cherry, apple, etc.	Near trees	Purple and blue above, six red spots on under surface of wings
	Banded purple	2½	July	Hawthorn	Open woods	A broad white band across both wings
	Viceroy	2½	June, Aug.	Poplar, willow	Roadsides	Imitates the monarch, but is smaller and has a black line across the hind wings
The Satyrs	Grass nymph	1¾	July	Grass	Meadows	Dull brown, twenty spots in two rows across the wings
	Little wood satyr	1¾	July	Grass	Hillsides	Dull brown, six spots
	Wood nymph	2	July	Grass	Hillsides	Dull brown, two eye spots on each fore wing in a larger yellow spot
Hairstreaks	Hop hairstreak	1⅛	May, July	Hop	About shrubbery	Dark color, hind wings have slender tail-like projection and black spots crowned with crimson
The Coppers	American copper	1	May, June, Sep.	Sorrel	Everywhere	Orange-red fore wings spotted with black, hind wing with orange border
The Blues	Common blue	1	May, July	Pea	Roadsides	Male light violet, female lighter with reddish bordered wings
	Tailed blue	1	May, Aug., Sep.	Clover, etc.	Roadsides, fields	Purplish violet color, has small tail-like projection on hind wings
The Whites	Common white	2	May, July, Sep.	Mustard family	Gardens	White checkered with black on fore wings, female brownish
	Cabbage butterfly	2	May, July, Sep.	Cabbage, etc.	Gardens	White, black tip on fore wing, one or two spots on hind wing
The Sulphurs	Common sulphur	m. 1¾, f. 2¼	May, June, Sep.	Clover	Meadows	Yellow, bordered with black
	Cloudless sulphur	2½	July	Cassia and legumes	Fields	Canary-yellow color
The Swallowtails	Tiger swallowtail	3–5	June, Aug.	Cherry, tulip tree	Open woods	Yellow with black lines across wings
	Black swallowtail	3–4	June, Aug.	Parsley	Gardens, roadsides	Black with two bands of yellow spots and one band of blue spots
	Green-clouded swallowtail	3¾–4¾	June, Sep.	Spice bush, sassafras	Open woods	Black, one row yellow spots, hind wing clouded with green
	Blue swallowtail	3¾–4¼	July, Sep.	Dutchman's pipe vine	Near houses	Black shaded with blue green, one row whitish spots

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CHAPTER III
THE CONNECTION BETWEEN STRUCTURE AND FUNCTION

1. A STUDY OF THE CELL AND OF PROTOZOA

To show what Single Cells can Do

Materials.

Some single cells of plant or animal tissue, stained to show structure. Slides of a one-celled animal, stained. Living one-celled animals.

Definitions.

Cell, the smallest living unit. Protoplasm, the living material composing the cell. Nucleus, a dense bit of protoplasm, usually near the center of the cell, often staining dark. Cytoplasm, the less dense protoplasm outside of the nucleus, usually taking a lighter stain. Nucleolus, paranucleus or micronucleus, a very small, dense, dark-staining body, either within the nucleus (nucleolus) or near it (paranucleus or micronucleus) Cell wall, the lifeless membrane surrounding many cells, secreted by the protoplasm. Food balls, bits of food inside the cells of many one-celled animals, usually showing through the walls. Food vacuole, a small drop of water containing digestive material and a food ball. Contracting or pulsating vacuoles, small, clear spots in the cell, filled with water. In the living cell these disappear at intervals and then appear again. Oral groove, a funnel-shaped groove in one side of some one-celled animals, conducting food to the mouth. In paramecium it often shows as an oblique line when the animal rolls. Gullet, the inner end of the oral groove. Cilia, numerous minute, vibrating, protoplasmic hairs on the surface of many cells. Respiration, the passage of oxygen into the tissues of a living organism and of carbon dioxide out of them. These gases can pass through any thin, moist, organic membrane. When such a membrane separates two fluids which differ in the amount of oxygen they contain, oxygen passes to the fluid containing the smaller amount.[2] The same is true of carbon dioxide. Respiration is believed to occur in all living organisms. Digestion, the process of making food materials soluble, so that they can pass through membranes and be used to build up protoplasm. A few forms of cells are able to take in solid food and digest it in their protoplasm, but most cells can admit only fluid food. Fission, a method of reproduction used in all cells, by which a cell divides itself into two, usually through the center. In some one-celled animals this may be preceded by conjugation, when two animals unite temporarily and exchange nuclear substance; or in some forms two cells may fuse and the resulting cell may divide. Budding is a form of fission in which a small projection is formed on the parent cell and then cut off, making a new individual. Protozoa (first animals), animals of one cell, existing alone or in loose colonies.

Observations.

1. Examine a single cell, stained to show structure. Identify the nucleus, cytoplasm, and, if present, the nucleolus or the micronucleus, and the cell wall. Draw to show the form of the cell and the details of its structure. Label all details.
2. Examine some stained paramecia. Select a typical one and identify in it nucleus, micronucleus, cytoplasm, and cell wall or cell membrane. You may also be able to see vacuoles, looking like holes in the stained protoplasm. Give reasons for considering this animal to be a single cell. Draw one, to show its cellular structure. Label all details.
3. Clean a slide and cover glass, place a drop of water containing living paramecia on the slide, cover it, and examine. What structures do you see which you saw in the stained paramecia? What structures do not show? Identify any new structures you may observe. Identify also the leading end and the side containing the oral groove.
4. Describe the shape of the animal.
5. What is the actual length of the animal?
6. After watching the animal for some time, describe the path followed by a given specimen as it crosses the field of the microscope. What reason can you see, if any, why this paramecium is moving? What external factors, if any, seem to determine the path it follows?
7. How rapidly do paramecia really move? What structures do they use in locomotion?
8. How do they manage to move in one direction, instead of alternately backward and forward? How do they manage to move in a straight line, though their bodies are not symmetrical?
9. What is the food of the paramecia? How do they find it? Find a specimen at rest and watch the oral groove. Suggest a method by which food may be collected into it. If possible, note the process of swallowing, and the resulting food ball.
10. Note.—If powdered carmine be placed in the water with some paramecia, it can be seen in the food balls a half hour or so later.
11. Where are the food balls located? Watch them in an individual until you notice their motion. Where are the larger food balls? the smaller ones? Assuming them to have been of approximately equal sizes when they were taken in, how can you account for differences now?
12. Where are the contracting vacuoles? How many are there? How often does one contract?
13. What is their function?
14. As you have been studying paramecia, to what external influences (as contact, heat, light, etc.) have you seen them respond? How do they show it when they do respond? Is such a response an advantage to them or not? What would be the result if they were not able to detect changes in their surroundings?
15. Where does respiration occur in paramecia? Where do they obtain their supply of oxygen?
16. Among the paramecia you are studying you usually find at least one in the process of fission. Watch it until the halves separate, if you can. Compare the halves. Do they rank as parent and offspring? If so, which is which? If not, which are they, parent or offspring?
17. If you happen to find a pair conjugating, notice the process, as far as you can, in the living animals.

Suggested drawings.

1. A drawing to show all the details seen in the living paramecium.
2. A diagram to show the path followed by a paramecium to get around some obstacle.
3. Drawings to show that paramecia are constant in shape and yet flexible.
4. A drawing to show at least one stage in fission. This may be from a permanent preparation.
5. A drawing to show paramecia conjugating. This also may be from a permanent preparation.
6. Instead of all these separate drawings they may be combined into one. Represent the field of the microscope, and in it draw all necessary figures, to show the facts called for in the first five drawings and any other facts you have observed about living protozoa. Make the whole drawing to scale.

Summary of Important Points in the Study of Paramecia

1. Look back over your study of paramecia and list the different kinds of work you saw paramecia doing; also the kinds of work you infer they can do. What organs have they to use? When there is no organ to do a given thing, e.g. to digest food, how is the work done?
2. What conditions are favorable to paramecia? Why are they so numerous under favorable conditions?
3. What would you call a successful animal? Are paramecia successful? Give reasons why they are or are not.

Comparative Study of Protozoa

To enlarge your idea of what a cell can do, spend as much more time on the one-celled animals as your course will permit. Any stagnant water may furnish several kinds. By means of reference books, identify as many as you can. In each case notice:—

1. Its size, shape and general appearance, comparing and contrasting it with paramecium.
2. Its usual surroundings, i.e. the conditions it has to meet.
3. The means it has of finding out facts about its surroundings.
4. The means it has of adjusting itself to its surroundings. For example, is it stationary? If so, what does it do when conditions change? Is it locomotory? If so, how effective is its locomotion?
5. What is its food? How does it find food?
6. Can it do as many kinds of work as paramecium can? Can it do any that paramecium cannot do? If so, what?

Review and Library Questions on Protozoa

1. What are the characteristics which distinguish protozoa from other animals?
2. What are the classes of protozoa? Characteristics of each class?
3. What is digestion? Where does it take place in the protozoa?
4. What results from the fact that the amœba has no cell wall? (Give at least two points.)
5. In what ways are paramecia more specialized than amœba are? How does their greater specialization show in their work?
6. What different methods of locomotion are shown among protozoa? By what means is locomotion accomplished in each case?
7. What is encysting? Name some protozoa which encyst. How long may an encysted animal live? When do they encyst? Why?
8. Give methods of reproduction among protozoa. Which method is fitted for rapid multiplication, for withstanding drouth; for renewing vitality?
9. Many scientists speak of protozoa as immortal. What argument is there to support such a statement?
10. Why are no protozoa large animals? Give at least two reasons.
11. Why are protozoa so numerous? Why more numerous in stagnant water?
12. Where are protozoa found?
13. Why are protozoa so widely distributed?
14. Write the probable history of a piece of chalk.
15. What connection is there between protozoa and some polishing powders?
16. Where in the human body are malarial protozoa found? How are they transferred from one human being to another? Why is there likely to be more malaria in newly settled regions than in older ones? If you were obliged to spend some time in a region where malaria existed, what precautions would you take?
17. Name other diseases caused by protozoa. How are they fought?
18. What beneficial effect have some protozoa upon the water of stagnant ponds and ditches? How may some forms injure water for household purposes?
19. Give at least three reasons for thinking that protozoa are the most ancient animals.
20. Why are protozoa of great importance to the world?

2. A STUDY OF SPONGES

To show how cells loosely associated may work together.

Materials.

The simplest of the many-celled animals are the sponges, which, with one exception, are salt-water forms. That one, the spongilla, is not easily found and is very difficult to maintain in the laboratory. For these reasons the material for this study is very meager, except at the seashore, and much of the work must be done from diagrams and reference books. Small simple preserved sponges and complex toilet sponge skeletons will also be used.

Definitions.

Body wall, the outer wall in bodies of the many-celled animals. Central cavity, the cavity surrounded by the body wall in the simpler many-celled animals, as in the sponges. Canals, channels through the body walls of sponges. Inhalent pores, the outer ends of the canals. Ostia, the inner ends of the canals. Osculum, the large opening of the central cavity, at the distal end of the sponge. Spicules, tiny needles of mineral substance found in the walls of many sponges. Fibers, flexible threads of horny material found in the walls of many sponges. Endoderm cells, cells lining the canals. They have cilia or flagella (projections larger than cilia). Ectoderm cells, cells covering the outside of sponges and some other animals. In sponges it is believed that endoderm and ectoderm cells are able to exchange positions and functions. Mesoglea, a jelly-like layer between the endoderm and ectoderm layers. In the sponges this contains many wandering cells, probably from the other layers. Porifera (pore bearers), animals with many more or less independent cells, supported by solid skeletal parts and penetrated by a system of canals which open on the surface as pores.

Directions.

Study a simple sponge to see the shape, size, and point of attachment. Identify the osculum. In a diagram of a long section of a simple sponge identify the central cavity, body walls, canals, inhalent pores, ostia, and osculum. In a simple sponge cut like the diagram identify the same structures. Do the same for the toilet sponge.

Study a diagram of a portion of the body wall, considerably enlarged. Identify the endoderm and ectoderm cells, the spicules or fibers, and, among the spicules or fibers, irregular amœboid cells, sometimes called mesoderm cells.

Examine a fragment or section of each kind of sponge under the microscope. Notice the arrangement, shape, and length of the spicules and of the fibers.

Test both kinds of sponges by dropping a bit of each into weak acid, and noting the results. Also burn a bit of each and notice the odor.

Questions.

1. What is the shape of a simple sponge? What enables a mass of cells to retain such a definite shape?
2. What seems to be the composition of the skeletons? Why is one type of skeleton rigid and the other elastic?
3. Since sponges are attached for most of their lives to stationary objects, suggest means for obtaining food and oxygen, and for getting rid of waste matter.
4. Although individual cells are sensitive, a sponge as a whole is not. What connection has this fact with the fact that sponges are stationary?
5. Compare simple and complex sponges.

Suggested drawings.

1. A view of a simple sponge. Label everything shown.
2. A diagram of a simple sponge split in halves. Show by arrows the path followed by the water as it passes through the sponge.
3. A few spicules.
4. A few fibers.

Summary of Important Points in the Study of Sponges

1. What are two functions of the spicules or fibers?
2. What are at least two of the functions of the endoderm cells?
3. What can you suggest as functions for the ectoderm cells?
4. In what cases do cells show "team work" in accomplishing an object?
5. What degree of specialization is indicated by the fact that the cells may exchange positions and functions?
6. What work can any single cell of a sponge do? Compare the work done by such a cell with that done by a paramecium.
7. What work can a whole sponge do? Compare that with the work done by a paramecium.

Review and Library Exercise on Sponges

1. What are the distinguishing characteristics of Porifera?
2. Sponges were once supposed to be plants. In what respect are they plant-like? What made students finally class them as animals?
3. How do sponges reproduce? How are they distributed to new locations?
4. Where, as to depth of water, do most sponges grow? Where, as to oceans? Where, as to latitude?
5. What are some of the difficulties which confront a stationary animal? How are they overcome?
6. To what class of sponges do the "toilet" sponges belong? Why?
7. What conditions are necessary for toilet sponges to thrive? Where are the best ones found? Where are they most numerous? How are they collected? How are they prepared for market?
8. What is man able to do toward raising good sponges for market?
9. Using reference books and museum specimens, describe some especially odd sponges.