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A GUIDE FOR THE
STUDY OF ANIMALS
BY A COMMITTEE FROM THE
BIOLOGY ROUND TABLE OF THE CHICAGO
HIGH SCHOOLS
WORRALLO WHITNEY, Chairman
BOWEN HIGH SCHOOL
FREDERIC C. LUCAS
ENGLEWOOD HIGH SCHOOL
HAROLD B. SHINN
SCHURZ HIGH SCHOOL
MABEL E. SMALLWOOD
LANE TECHNICAL HIGH SCHOOL
D. C. HEATH & CO., PUBLISHERS
BOSTON -- NEW YORK -- CHICAGO
Copyright, 1911,
By D. C. Heath & Co.
1 E 3
PREFACE
The following guide to the study of animals is intended for pupils in
secondary schools. It was prepared by the authors at the request of
the Biology Round Table, an association composed of the teachers of
Biology in the Chicago High Schools, to whom the authors wish to take
this opportunity of expressing their appreciation of the many helpful
suggestions and criticisms of the manuscript.
The time has passed when a high school course in zoölogy consists
simply of a somewhat simplified edition of a similar course in
college. All teachers now recognize that the motivization of any
course should be its adaptability to the needs of the student, and
that zoölogy must be taught from the standpoint of the student rather
than that of the subject. In preparing this guide, the authors have
tried to keep these points in mind.
The matter of presentation, the order of topics, and the choice of
material has been much discussed, but the trend of opinion has
finally set in toward an ecological rather than a type study of
animals; that there should be in the case of young students a brief
study of rather a large number of animals to bring out some general
biological law, rather than an exhaustive study of a very few types.
It is further recognized that the use of a reference library is
absolutely essential in connection with and to supplement the
laboratory work, as there are some topics beyond the ability of the
young student for original investigation as well as impossible in
the amount of time usually allotted to the subject in our crowded
curricula. Of great importance is the economic side of zoölogy,
especially its bearing upon the applied sciences of medicine,
sanitation, household science, and agriculture, and this phase has
received special attention in this guide.
The desirability of field work has always been recognized, but the
special conditions under which schools must work are so variable as
to make any set directions for field work of little value, and so
they have in most cases been omitted in this work. Each teacher can
easily give such special direction for collecting material and study
in the field as the locality of the school and the time available for
it shall determine.
Since zoölogy will probably be the pupil's first laboratory science,
the authors have preceded the more formal portion of the manual with
a series of short exercises on familiar and easily obtained animals
in order to introduce the pupil to the laboratory method and to
stimulate his interest, training him at the outset to be constantly
on the outlook for specimens and to show him how much may be learned
from common things right around him, if he will only use his eyes. We
have also begun the more formal portion of the guide with insects,
since in the fall they are easily collected and may be studied alive.
They illustrate, moreover, the principles of classification and
method of using keys and other means of finding out the names of
animals. This would seem to be pedagogically sound, for some recent
experiments with pupils show that the first question that comes into
a child's mind upon seeing a new or strange specimen is "What is it?"
A larger portion of the guide is given to the chordates than is
usually the case. The authors also believe that this is correct and
in accord with the natural interest of the pupil. It will serve to
connect his zoölogy more closely with his daily experiences.
There is material enough provided to allow the teacher a chance to
select that best adapted to his purposes or conditions as well as to
provide for those schools that give more than one year to zoölogy.
CONTENTS
PAGE
CHAPTER I
INTRODUCTORY STUDIES OF LIVING ANIMALS 1
Fly, 1; Maggot, 3; Cockroach, 4; Spider, 5; Cricket, 6; Grasshopper,
7; Butterfly or Moth, 9; Caterpillar, 10; Tussock Moth, 11; Beetle,
13; Damsel Fly Larva, 14; Plant Lice and Scale Bugs, 15; Water Bugs
and Beetles, 17; Getting Acquainted with the Library, 18.
CHAPTER II
STUDIES OF INSECTS 20
Field Studies, 20; Grasshoppers or Locusts, 23; Comparative Study of
Orthoptera, 28; Key to Orthoptera, 29; Dragon Fly, 30; Honeybee, 31;
General Study of Insects, 33; Review of Insects, 35; Key to Principal
Orders, 36; Some Common Butterflies, 38; Summary of Insects, 37;
General Review and Library Exercise, 40.
CHAPTER III
THE CONNECTION BETWEEN STRUCTURE AND FUNCTION 44
_Protozoa_: A Study of the Cell, 44; Comparative Study, 48; Review
and Library Exercise, 49; Sponges, 51; Review and Library Exercise,
53. _Coelenterates_: Hydra, 54; Comparative Study, 58; Review and
Library Exercise, 59. _Worms_: Living Earthworm, 61; External
Morphology, 64; Internal Morphology, 64; Microscopic Anatomy, 66;
Summary, 68; Review and Library Exercise, 70; Connection between
Structure and Function, 72.
CHAPTER IV
ADAPTATION TO SURROUNDINGS 73
_Crayfishes_: Living Crayfish, 73; Morphology, 75; Summary, 79;
Review and Library Exercise, 81.
CHAPTER V
ADAPTATION FOR PROTECTION FROM ENEMIES 83
_Mollusca_: Clam, 83; Snail, 87; Squid, 89; Comparative Study, 91;
Review and Library Exercise, 92. Comparative Study of Exoskeletons,
93; Protective Coloration, 94; Animal Associations, 96; Protective
Habits and Powers, 98; Defensive Structures, 99; Thesis: "Adaptation
for Protection," 99.
CHAPTER VI
VERTEBRATES 101
_Fishes_: Living Fish, 101; External Structure, 103; Mouth and Gills,
105; Alimentary Canal and Circulatory System, 107; Review and Library
Exercise, 110. Primitive Chordates, 112. _Amphibia_: Living Frog or
Toad, 114; Mouth, 116; Organs of Digestion, Absorption, and
Excretion, 117; Organs of Circulation and Respiration, 120; Nervous
System, 123; Endoskeleton, 125; Comparative Study, 129; General
Review and Library Exercise, 129. _Reptiles_: Living Snake, Lizard,
and Turtle, 130; Review and Library Exercise, 132. _Birds_: Living
Pigeon, 133; Plumage, 136; Birds and Migration, 139; Laboratory
Exercise, 139; Field Work, 141; Review and Library Exercise, 142;
Migration in General, 145. _Mammals_: Rodents: Domestic Rabbit, 146;
Wild Rabbit, 148; Guinea Pig or White Rat, 149; Squirrel, 150;
Library Exercise, 152. _Carnivora_: Laboratory Exercise, 153; Library
Exercise, 155. _Ungulates_: Laboratory Exercise, 157; Library
Exercise, 160. The Horse, 162. Homology of the Vertebrate Skeleton,
168.
CHAPTER VII
ADAPTATIONS FOR THE PRESERVATION OF THE SPECIES 170
Methods of Reproduction: Simple or Asexual Method, 170; Complex or
Sexual Method, 171. Development: Structure of an Egg, 172;
Development of an Egg, 173; Metamorphosis of a Mosquito, 174;
Metamorphosis of a Butterfly, 176; Development of the Chick, 177.
Protection and Care of Young: Library Exercise, 179. Adaptation for
the Preservation of the Species: Review and Library Exercise, 180.
CHAPTER VIII
POULTRY 182
* * * * *
GLOSSARY 189
A GUIDE FOR THE STUDY OF ANIMALS
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._
a. 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._
a. 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._
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?
Find out the name of your kind of spider.
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.
_Suggested drawings._
a. The entire spider, seen from above.
b. 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._
a. The butterfly or moth.
b. 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._
a. A caterpillar, × 2.
b. A cocoon with its egg mass.
c. A pupa as seen from the under side.
d. 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._
a. The entire larva, × 4.
b. A gill, as seen through the microscope.
c. 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._
a. A single aphis as seen with hand lens.
b. Various scale bugs as seen with a hand lens.
c. 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._
a. The dorsal view of both bug and beetle.
b. 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.
a. Advanced textbooks.
b. Elementary textbooks.
c. Natural histories.
d. Books for classifying or naming animals.
2. Descriptive books.
e. Life histories and habits of animals.
f. Adventures with animals--popular accounts of animals seen on
walks and travels.
3. Economic zoölogy.
g. Books on harmful animals and methods of destroying them.
h. Books on useful nondomesticated animals and their products.
i. Books on domestic animals.
j. 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.