CORNELL
UNIVERSITY
LIBRARY

FROM

The Dent. of Zoology

Palade University Library
QL 53.H

Ti

of zoology.

iil

mann

Cornell University

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924003410077

INTRODUCTION

TO THE STUDY OF

A00L0G ¥

FOR USE IN

HIGH SCHOOLS AND ACADEMIES

BY

N. A. HARVEY

Head Department Science, Chicago Normal School
Pres. Dept. Science, Nat'l Educational Ass’n, 1901

WESTERN PUBLISHING HOUSE
CHICAGO
ae

COPYRIGHT, 1901, BY
WESTERN PUBLISHING HOUSE

Zoology-—1-1

ROBT 0, LAW co.
PRINTERS ANO BINDERS
cHicaao

PREFACE.

Almost every text-book on logic draws the majority of its illus-
trations of logical processes from the development of the subject
matter of the natural sciences. The natural sciences most clearly
manifest the universal method of discursive thought; therefore, it
is difficult to overestimate their importance as an element in edu-
cation.

Of all the natural sciences, zodlogy is the one which can be
used with the greatest economy of effort to give the mind facility
in certain fundamental activities which lie at the foundation of
all processes of logical thinking.

As the writer conceives it, the pedagogical content of zodlogy
consists in training the pupil to gather knowledge at first hand and
to get clear ideas of the objects studied, and in exercising his mind
in its power of abstraction, concrete analysis, discrimination, com-,
parison, generalization, arid ldgical definition and in the recognition
of logical identity. The results of the study conducted under
the influence of such a conception are likely to be very different
from what they would be if it were believed that the knowledge of
a few animals is the chief end sought. To leave zodlogy out of a
course of instruction is to omit the training of the mind in. these
directions, or to accomplish the same result by a much greater ex-
penditure of energy in another subject than would be necessary in
this.

Just as the benefit derived from the study of algebra is not to
be looked for in the information conveyed in the answers to the
problems that the student so laboriously solves, and the value of
the study of Latin comes not from the knowledge of the historical
facts that the pupil learns while reading the Latin language, so the
value of the study of zodlogy does not depend upon the knowledge,
of animals that the student acquires, but rather upon the power
that the student acquires while gaining that knowledge.

A commendable text-book on zodlogy for high schools must
concern itself, then, not so much with the development of the sub-
ject as with the development of the human mind. This book is

3

4 PREFACE.

written fyom a pedagogical standpoint, and is intended to point out
so carefully the content of the subject, and to indicate so clearly
a method by which the content may be realized, that no teacher
and no pupil who follows the plan here indicated can fail to
realize a large part of the value to be derived from the study of
elementary zodlogy.

There are at least three stages in the study of zodlogy. First, .
the one in which the student learns how to study and how to utilize
zoological material. Knowledge of facts is a very subordinate aim
in this stage, and the method of acquiring knowledge is very im-
portant. This is the stage of greatest educational value, and is but
little transcended in highschool work. Itistheintroductory stage,
and justifies the name of Introduction for this book. The second
stage is the onein which knowledge of facts is the chief end sought.
It is essentially a reading stage. The student must read every-
thing about the subject, or that part of the subject to which he
turns his attention. The third stage is one in which the student
undertakes original investigation and adds to the world’s stock of
knowledge.

This analysis shows us that the work of the introductory stage
must be largely laboratory work. The writer fails to see how very
much good can be obtained from the study of a science that is not
pursued in this way. Even the reading of books is not to be rec-
ommended, unless they deal with phases of the subject that are
not investigated in the laboratory, although in a few instances it
has seemed impracticable to avoid giving some information in the
text that might be derived from the study of the specimen itself.

In this book it is intended to combine the advantages of Natural
History study with laboratory work in such a way that neither
shall detract from the value of the other. Under the head of ‘‘Addi-
tional Facts’’ are stated life relations and habits of the animals
studied which cannot be determined from an examination of their
structure. Completeness or fullness in this respect is neither at-
tempted nor desired, but enough is given to stimulate observation.
The natural history text is limited to the animal forms studied
in the laboratory, or to closely related animals, for it is very doubt-
ful whether the reading about animals foreign to one’s locality or
experience is at all conducive to observation.

The principal emphasis is laid upon the branch of Arthropods,
and the subject of insects is treated first. This is done deliber-
ately and after much thought and trial of other ways. The first

PREFACE, 5

insects studied represent different families. By a comparison of
these insects we generalize and rise to the conception of an Order.
The next insects studied represent orders, and by a comparison of
their resemblances we proceed to the conception of a Class. The
table of differences enables us to frame a logical definition of each
order. The next animals studied represent not orders, but classes.
By a comparison of all these animals, we generalize and rise to the
conception of a Branch. The next animals studied represent
branches, and a similar process of the mind leads to the conception
of a Kingdom.

It might be possible to use Vertebrates instead of Arthropods for
the purpose .of forming a conception of the less comprehensive
groups, but the inconvenience would be greater. Near the seashore
it might be possible to use Mollusks instead of Arthropods as the
beginning of the work, but certainly not with such satisfactory
assurances of success.

Because of the importance of vertebrate dissection in the study
of human physiology, more attention is given to the Vertebrates
than is really demanded by the logical development of the plan.
The importance of Protozoa in the discussion of philosophic ques-
tions leads toa treatment of the subject seemingly inconsistent
with the rest of the book, but which it is believed will prove an
advantage to the users.

Certain philosophic principles are discussed, when occasions
arise demanding their treatment, but nothing is touched upon that
does not grow directly out of the laboratory work. Such are the
topics of Protective Coloration, Mimicry, Protective Resemblance,
Vestigial Organs, von Baer’s Principle, Homology of Parts, Meta-
morphosis, Variation, Development, Economic Effect, Parasitism,
Senses and Sense Organs.

Enough work is suggested to occupy the time of a class one
period each day for one year of nine months. Ifa shorter time is
given to the study, the teacher may make a selection in one of two
ways. He may lay the emphasis upon a smaller number of groups,
or upon a smaller number of animals in each group. According
to the second plan, a good selection would be to study only the
grasshopper, butterfly, beetle, housefly, crawfish, rabbit, clam, earth-
worm, starfish, hydra, sponge, paramcecium. The writer considers
it more advantageous to limit the study to Arthropods if the time
is very short.

This book is the outcome of ten years’ experience in teaching

6 PREFACE.

elementary zodlogy to large classes, and everything indicated in it
has stood the test of class-room work many times. It will be found
serviceable in a laboratory that is well equipped for work, but is
especially designed for those high schools whose equipments are the
most meager and whose only hope of obtaining better facilities
for teaching lies in making a success of the work with the facilities
they already have.

The illustrations are nearly all of microscopic objects, and the
only purpose in inserting them is to assist pupils that have not
the opportunity to use a compound _microscope.

Special attention is called to the forms of the tables of resem-
blances and differences, and to the demonstration of the homology
of the mouth parts of the grasshopper (page 66), to the treatment
of von Baer’s Principle (page 99), to the three series (page 103),
and to the demonstration of rank among animals (page 167).

Gratefulacknowledgments for valuable suggestions are rendered
to Prof. S. A. Forbes and Dr. Frank Smith of the University of
Illinois, to President Howard Ayers of the University of Cincinnati,
and to Dr. Frank J. Hall of the Kansas City Medical College.

SYNOPSIS OF CHAPTERS.

PAGE
DIRECTIONS TO STUDENTS........c:.ceceee ee ceee ceeteeeeeeeenceecreneesereere 9
CHAPTER I.—THE GRASSHOPPER ..... 10. cece cee ee ects cece eset eeeeeeeeee 13

Laboratory directions—Pronunciation lists—The living grasshop-
per—Microscopic objects: compound eye, crop, air tubes, eggs, and
muscle— The young grasshopper— Examination questions— Review
topics—Additional facts: the skeleton, molting, metamorphosis, senses,
respiration, injuries to farm crops—Groups of animals—Rules for
naming.

CHAPTER II.—OTHER ORTHOPTERA. ait SSA ath. reteateres jo teeanea
The cricket—Laboratory directions dditional facts: color,
ositor, deposition of the eggs—Microscopic objects: spiracle, gizzard,
le on the wing—The katydid—Laboratory directions—Additional facts
—The walking-stick—Laboratory directions—Additional facts: protec-
tive resemblance—Table of differences between the grasshopper, cricket,
katydid, and walking-stick—Table of resemblances —Additional facts
about the Orthoptera.

CHAPTER III.— OTHER INSECTS...............05- Signa Geayebibesisia ae 318 Wsieeaien daaaite
The butterfly—Laboratory directions—The caterpillar—Laboratory
directions—The chrysalis and cocoon—Laboratory directions—The moth
—Laboratory directions—Table of differences between a butterfly and a
moth—Microscopic object: scales of a moth—Additional facts about
Lepidoptera: metamorphosis, mouth parts and their homology, mim-
icry, silk, injurious Lepidoptera—The beetle—Laboratory directions—
Additional facts—The giant water bug—Laboratory directions—Addi-
tional facts—The cicada—Laboratory directions—Additional facts: the
seventeen year cicada, injuries produced by Hemiptera, parthenogenesis
—The house fly—Laboratory directions—Microscopic objects: proboscis,
labelle, lancets and palpi, foot, wing—Additional facts—The dragon fly
—Laboratory directions—Additional facts—The bumblebee—Laboratory
directions— The wasp— Laboratory directions — Microscopic objects:
tongue of a bee, tongue of a wasp, sting of a wasp, hooks on the hind
wing—Additional facts about Hymenoptera: metamorphosis; social
organization; honey, nectar, pollen, and wax; use of the sting and
poison; cross fertilization of plants; warning coloration; habits of
solitary wasps; intelligence of ants—List of orders of insects—Pronun-
ciation lists—Table of differences between insects—Table of resemblances
—Logicl definition- Definition of each order—Review topics on insects
—General considerations about insects: how to collect and preserve
insects.

CHAPTER IV.—ARACHNIDA AND MYRIAPODA.......... 2 cceeee cece eee ee
The spider—Laboratory directions— Daddy longlegs—Laboratory
directions—Additional facts about Arachnida—The centipede—Labora-
tory directions— Thousand legs— Laboratory directions — Similarity
between a caterpillar and a myriapod—Additional facts about myria-
pods: habits of life, homology of the maxillipeds, demonstration of the
homology between the legs and the mandibles of a grasshopper.

CHAPTER V.—CRUSTACEA....... 000 ce settee nee cee etter cette nett t et eee:
The crawtish—Laboratory directions—Internal structure—The living
crawfish —The sow bug — Cyclops — Daphnia —Additional facts about

32

61

68

8 SYNOPSIS OF CHAPTERS.

Crustaceans—Review topics—Table of differences between a grasshopper,
spider, centipede, and crawfish—Table of resemblances—Definition of
an Arthropod.

CHAPTER VI.—THE FISG.......... cee cece ete cee e een cence eeee seen nana nes
Laboratory directions —The live minnow—Additional facts about
the fish: orders, method of breathing, action of gills, method of distri-
bution, single circulation, homology of the air bladder—Review topics-
Vocabulary.

CHAPTER: VIl—BATRACHIA sevice mera ve een chee aecomaaae
The frog—Laboratory directions— Additional facts: method of
breathing, circulation—Microscopic object: blood corpuscles—The toad—
Table of differences between a toad and a frog—Tadpole —Laboratory
directions—Comparison of a tadpole and a fish—Demonstration of von
Baer’s principle--The three series: ontogenetic, phylogenetic, taxo-
nomic—Review topics on the frog.

CHAPTER VIII.—BiRDS AND REPTILES...
The pigeon—Laboratory directions—Feathers—An egg—Table of
differences between a pigeon and a fish—Additional facts: feathers,
wing muscles, teeth, circujlation, breathing, embryology, egg, air space,
migration—Review topics on the pigeon—The turtle—Laboratory direc-
tions—Table of resemblances between a turtle and a pigeon—Additional
facts—Archeopteryx.

ences between a grasshopper and a rabbit—Additional facts about mam-
mals: teeth, injuries, rabbits in Australia, checks on increase, pressure
on subsistence, struggle for existence, survival of the fittest -Addi-
tional facts about vertebrates: amphioxus, notochord, vestigial organs.

CHAPTER X.—OTHER INVERTEBRATES... 22.0. ..0006 cece cece eee beens

The fresh-water clam—Laboratory directions—Suggestive ques-
tions—Facts about the clam—The oyster—Table of differences between
the oyster and the clam—Table of resemblances—The snail—Laboratory
directions--Table of differences between the clam and the snail—Table
of resemblances—Facts about the snail—Microscopic object: odonto-
phore—The earthworm--Laboratory directions--Facts about the earth-
worm: breathing, locomotion, life habits, other worms--Microscopic
object: cross section--Table of differences between a caterpillar and an
earthworm—The starfish--Laboratory directions--Facts about the star-
fish: bilateral symmetry, water-pipe system--Review topics on the
clam, snail, earthworm, and starfish—Fresh-water hydra—Laboratory
directions—Facts about the hydra—Fresh-water sponge—Laboratory
directions—Facts about the sponge--Protozoa: vorticella, carchesium,
epistylis, stentor, paramcecium, amoeba--Table of resemblances among
vorticella, stentor, paramcecium, amoeba—-Concept of a protozoan—Facts
about the protozoa: practical immortality, reproduction, undifferenti-
ated cell—Table of resemblances among rabbit, clam, grasshopper,
earthworm, starfish, hydra, sponge, and paramoecium--Concept and
definition of an animal—Differential table showing addition of organs
to the different groups--Demonstration of rank among animals--Logical
definition of each branch—-General review topics.

CHAPTER XI.—COLLECTING AND PRESERVING MATERIAL .............-
(With Suggestions upon its Management in the Class.)

CHAPTER XIL--CLASSIFICATION OF ANIMALS.......... .

91

INTRODUCTION

TO THE STUDY OF

LO O TOG Y.

DIRECTIONS TO STUDENTS.

The value of this work to you will depend largely
upon how much of it is done without assistance. You
are to acquire definite and exact information. of the
objects studied for the sake of learning how to acquire
definite and exact information of objects in general.
The solution of a problem in algebra is valuable not
for the information acquired in the answer, but for
the power acquired in learning how to find the
answer.

The information about each specimen studied
should be obtained from the specimen itself as far as
such information can be thus obtained. It is a mis-
take to go to reference books, or to ask your neighbor
or your teacher, for information about the specimen
that the specimen itself can tell you. Some things
the specimen cannot tell. Under the head of ‘‘ Addi-
tional Facts,’’ this book states some of the things
about the animals studied which the specimens can-
not tell. After an animal form has been studied, it
is a good thing to read about it, but the reading should
follow and not precede the laboratory study.

9

10 INTRODUCTION TO ZOOLOGY.

You should keep in a notebook a faithful record
of all your observations. Each observation should
be written out in full, in ink, at the time it is made, in
order that it shall be as complete as possible. ‘‘Writ-
ing makes an exact man.’’ Do not try to make crude
notes on a scratch-book and copy the notes afterward.
Your book may thus become a copy-book, but it will
not be a notebook. Sometimes an erroneous obser-
vation will be recorded. Insuch acase, the correction
should be recorded in the notebook just when it is
discovered, with the statement that an erroneous
observation has been recorded on a certain preceding
page. Nothing should be copied into the notebook
from another book. It should contain only the record
of your personal observations.

The drawings should be the best that you are
capable of making. It will be found the most satis-
factory to make the drawings with India ink, on good
smooth paper, using a fine-pointed pen. The draw-
ings should be line drawings, and every line should
represent something on the object, and not be put in
merely for looks. Drawing is a method of study, and
everything that is studied should be drawn. The
drawings, like the notes, should be made while the
object is before you. Do not copy pictures from
books. Copied pictures are worse than useless for
purposes of this study.

There are two kinds of questions that you will be
disposed to ask. One is a proper kind and one is an
improper kind. For example, on the grasshopper
you may be disposed to ask, ‘‘ Where is the labial
palpus?’’ This is an improper question. It means
that you have somehow got hold of a name, and now
are asking some one to show you the thing that fits
it. The proper reply to your question is to say, ‘‘Ask
the grasshopper.’’ The other kind of question is a
proper one. You say, ‘‘I have found something

DIRECTIONS TO STUDENTS. 11

here. What is it?’’ You have found the thing.
The name is not printed upon it, of course,
and as the name is merely something that has
been agreed upon by men to designate that thing, it
must be given to you either by your book or by your
teacher.

In all your work you must regard the animal as a
living thing. It is not true that you are studying
merely a dead form. On the grasshopper we study
the eyes, because he sees with them; we study the
antenne, because he feels with them; the mouth
parts, because he bites with them; the spiracles,
because he breathes with them; the wings, because
he flies with them; and so with every other struc-
ture that we study, it has some use or some mean-
ing in the life of the animal, and it is a part of
our work to see what that meaning is and to see
how all the parts work together to enable the animal
to live the life that he leads. Wherever possible,
of course, the living animal is to be studied in its
home.

The purpose of the laboratory directions in this
book is to direct your study and not to give informa-
tion. It is very difficult not to give too much infor-
mation in the laboratory directions, but the attempt
has been made to avoid it.

Much of the benefit to be derived from the study
of zodlogy can be obtained from the study of the
specimen even though you be supplied with the most
meager apparatus. The hand lens seems to be the
only piece of apparatus that is absolutely indispen-
sable, although a better equipment will contribute
very much to the efficiency of your work. You ought
to have a copy of the text-book to guide you in the
work, a specimen of the object to be studied, a note-
book, and pen and ink with which to record your
observations and make your drawings; you ought

12 INTRODUCTION TO ZOOLOGY.

also to have a set of dissecting instruments, consisting
of a lens, a scalpel, a pair of small, sharp-pointed
scissors, and a pair of fine-pointed forceps; you
should also have a dissecting dish, a small jar
or wide-mouthed bottle for preserving your alco-
holic material from day to day, a towel, and a piece
of soap.

Suggestions about the collection and preservation
of material and laboratory devices and management
will be found in a chapter near the end of the book.

CHAPTER I.

THE GRASSHOPPER.

1. Distinguish the head, thorax, and abdomen.
These are called the body divisions.

The Head.

2. Find the antenne. How many segments in
each?

3. Find the compound eyes. Your lens will show
only some fine lines running criss-cross over the sur-
face. .
4. Find three simple eyes (ocelli) on the head.

5. See the upper lip (labrum). Raise it. Cut it
off. Examine the under side. Draw.

6. See the mandibles, or true jaws. Pry them
apart. In what direction do they move? Pull one
off. Examine. Draw.

7. Below the mouth is the labium, or lower lip. Is
it a single appendage, or two united?

8. Find the labial palpi, attached to the labium.
How many segments in each?

9. Find the maxille. These consist of three
pieces each :—

(a) Maxillary palpus. How many segments?

(b) A spoon shaped piece, the galea.”

(c) The lacinia, or maxilla proper. How many
points has it?

10. Draw the head, as seen from the side. As seen
from the front.

13

14 INTRODUCTION TO ZOOLOGY.

The Thorax.

1. Locate the three parts of the thorax. The front
one is the prothorax. This has no wings. The
middle one is the mesothorax. The hind one is the
metathorax.

2. Find a small opening just above the second
pair of legs. This is a breathing pore, or spiracle.
Find another in the soft skin between the pro- and
mesothorax. ;

3. How does the prothorax differ from the meso-
and metathorax? What is the advantage of the con-
solidation of the meso- and metathorax?

The Wings.

1. Spread out the fore and hind wings on the right
side of the body. Draw both in this position.

2. To what part of the thorax is each wing at-
tached?

3. Find the veins which constitute the framework
of the wings.

4. State the difference between the fore and the
hind wing, with reference to size, shape, color,
texture, folding, use, position when at rest and when
in motion.

The Legs.

1. Examine one of the hind legs. To what part of
the thorax is it attached?

2. Find a short segment close to the body, the coxa.

3. Find the large segment (femur). The next seg-
ment is the tibia. See the spines behind. What is
their use? The end of the leg is the tarsus. How
many segments has it? Study the feet.

4. Examine the joint between the tibia and the
femur. Draw the whole leg.

THE GRASSHOPPER. 15

5. Study one of the front legs in the same way.
Note especially the foot. State how the front leg dif-
fers from the hind one. Draw.

6. In how many ways can a grasshopper travel?
What difference in the use of the front legs and the
hind legs?

‘7. Remove the legs and wings and draw the tho-
Trax, as seen from the side. As seen from below.

The Abdomen.

1. Locate the tergum, which is the upper or dorsal
side of the body; the sternum, which is the ventral or -
lower side ; and the pleurum, which is the lateral part
between the sternum and the tergum. See the two
grooves along the sides.

2. Count the segments of the abdomen. The last
two do not go entirely around.

3. Find spiracles, or breathing holes, along the
upper edge of the side grooves. How many? :

4. Find the ear, on the first ring of the abdomen,
under the wings. Is there a spiracle on this segment
also?

5. If your specimen is a female, find the ovipositor,
consisting of four parts, at the end of the abdomen.
Draw.

If your specimen is a male, the end of the abdo-
men will be blunt and you will find two hooks (cerci)
above it. Draw.

6. How many segments in the abdomen? How
many in the thorax? How many pairs of paired ap-
pendages on the head? If each pair of appendages
indicates a segment, how many segments in the head?
How many segments make up the entire body?

7. Draw a side view of the entire grasshopper.

8. You ought now to have a drawing of the whole
grasshopper, two views of the thorax, two views of the

16 INTRODUCTION TO ZOOLOGY.

head, a drawing of each of the mouth parts, antenne,
ocelli, two legs, wings, and ovipositor.

9. What color is your grasshopper? Is this color
an advantage? Would it be well for the grasshopper
if it were bright red or blue or yellow? Are all
grasshoppers the same color? Why?

10. Copy the following words into your notebook.
Spell, pronounce, and tell what each word means.

ab do’/men pro tho’rax
thd’rax més’o thd’rax
an tén’ne mét’a thé’rax
1a’brum c6x’a

1a/bi um tro ehin’ter
max il'la fé/mur
mix'il lary pal’pus tibia

o ¢él'lus tir'sus

spir’a cle 0 vi pos'i tor
min’di ble gér’Gi

11. What do grasshoppers eat? Are they inju-
rious to crops? Why are they not injurious every
year? How many kinds of grasshoppers can you
collect?

12. Cana grasshopper feel? See? Hear? Smell?
Taste? With what organs can he smell? Taste?

13. How does a grasshopper escape from his
enemies? What enemies?

14. How long does a grasshopper live?

Internal Structure.

1. Cut off the wings of a grasshopper that has
been freshly killed. Pin it, back upward, on cork, in
a dissecting dish full of water. The cork must be
sheet cork, weighted down with lead so as to sink in
the water.

THE GRASSHOPPER. 17

Stick one pin through the tip of the abdomen, and
another through the femur of each hind leg. Cut with
scissors just through the body wall, along each side
of the body from the tip of the abdomen to the head.
With forceps, lift the flap between the cuts, scraping
away the tissues below it with the scalpel. Study.

2. Find the air sacs along each side. How many?

8. Find the air tubes, or trachee. Trace them to
the spiracles.

If the grasshopper has been preserved in alcohol,
the trachez and air sacs will not show very plain;
but in a freshly killed specimen they will be filled
with air and will show as silvery white tubes.

4. Find the large muscles in the thorax that move
the wings.

5. If your specimen is a female, see the ovaries
and the eggs. How many eggs? How arranged?
What shape?

6. Trace the oviduct from the ovaries to the
ovipositor.

7. Thrust a blunt probe into the mouth. It passes
through the esophagus into the crop.

8. Find some double cone-shaped pouches just be-
hind the crop. These are the gastric ceca. How many?

9. Find the stomach.

10. Trace the intestine.

11. Draw the alimentary canal, showing cesopha-
gus, crop, ceca, stomach, and intestine.

12. Notice in the body many small red threads.
These are the urinary tubules. They are excretory
organs.

18. Carefully remove the digestive organs and
look for the nervous system lying along the floor of
the abdomen. Trace it through the thorax.

14. Is the nerve cord double or single? Find lit-
tle knots (ganglia) on the nerve cord. How many
ganglia in the abdomen? How many in the thorax?

18 INTRODUCTION TO ZOOLOGY.

15. See the nerves branching off from the ganglia.

16. In the head, between the compound eyes, find
the supra-cesophageal ganglion. Find the optic nerves
leading from this to the eyes. Trace the two parts of
the nerve cord from the supra-csophageal ganglion
around the cesophagus to the infra-cesophageal gan-
glion below the cesophagus.

17. Make a complete drawing of the nervous
system.

18. What drawings have you made?

19. Copy the following words into your notebook ;
spell; pronounce. Tell to what each term is applied.

w@ sdph’a gus gin’gli on o’va ry
gis’trie ovz’ca tra’ehe x ’vi duct
in tés’tine w@ so phig’e al tri na ry

Questions to be Answered by Observing a Live Grass-
hopper.

1. Watch the breathing. What movement is
visible in the abdomen?

2. Observe a spiracle. Does it open and shut?

3. In what order are the legs moved while walking?

4. Why does the grasshopper spit out ‘‘ molasses ’’?

5. Does the grasshopper have as good means of
breathing as man? Of locomotion? Of seeing?

To the Teacher.

The purpose of this study of the grasshopper is to train the pu-
pil to get knowledge at first hand and to get clear ideas of the object
studied, to give him practice in concrete analysis, and to train
him to use the mind in its power of abstraction. This purpose will
be defeated if he be told too much, if he besent to books of reference,
or be allowed to find an answer to the questions proposed by asking
another person. Itisnot the knowledge gained that is of value, but
the power acquired in gaining the knowledge. If the knowledge be
acquired in the wrong way, there can be but little gain in power.

THE GRASSHOPPER. 19

Microscopic Objects.

When viewed with a mi-
croscope, the surface of a
compound eye is seen to be
marked off into little spaces
called facets. These facets
are six sided, crowded
closely together, and each
eye contains from six to ten
thousand facets. Each fac-

et seems in some way to
represent a simple eye.

CROP OF GRASSHOPPER.

If the crop of a grasshopper
be split open, it will be seen to
be composed of two layers.
The inner layer has many
sharp-pointed teeth upon its
surface, arranged in rows or
groups. The teeth aid in tear-
ing the food to pieces.

EGGS OF GRASSHOPPER,

Each egg is seen to be en-
closed in a sac, the mouth of
which opens into the oviduct.
In the smaller end or tip of
the sac will be found two
or three immature eggs in
various stages of develop-
ment,

20 INTRODUCTION

TO ZOOLOGY.

AIR TUBES (TRACHE-®) OF GRASS-
HOPPER,

The trachez branch freely
and ramify throughout all
parts ofthe body. Each trachea
appears to be composed of a
fine thread wound spirally
around the tube.

MUSCLE FIBERS FROM THORAX OF
GRASSHOPPER,

The muscle is composed of
slender fibers, each of which is
marked by the transverse
stria, which are always consid-
ered indicative of voluntary
muscle.

The Young Grasshopper.

1. Examine the young

old one.

sasshopper as you did the

2. Notice the body divisions, head, antennie, eyes,
ocelli, labrum, mandibles, labium, labial palpi, max-
ill, maxillary palpi, thorax, wings, legs, abdomen,

spiracles, and ears.

3. Find, especially, differences in the eyes, wings,

and legs.

Suggested Examination Questions on the Grasshopper.

1. How many body segments in the body of a

grasshopper?

2. Name all the mouth parts of a grasshopper.
3. Draw the leg, naming all parts.

THE GRASSHOPPER. 21

4. State differences between the fore and the hind
wing.

5. How many pairs of spiracles on the body of the
grasshopper? On what segments do they occur?

6. Name all parts of the digestive system.

7. Where are the ears situated?

8. Describe and draw the nervous system.

9. Describe the position and structure of the an-
tenne.

10. How many eyes has the grasshopper? Where
are they located with reference to each other?

Review Questions on the Grasshopper.

How many segments in the abdomen?

How many spiracles on the abdomen?

What are the parts of a single segment?

How many segments in the thorax?

What appendages does each segment bear?

State the differences between the fore and the hind

wing.

Name all the parts of the leg.

Where is the ear?

How many segments in the tarsus?

10. Describe the eyes.

11. Describe the antenne.

12. Name all the mouth parts.

13. How many pairs of paired appendages on the
head? What are they?

14. How many head segments do they represent?

15. How many segments in the entire body of the
grasshopper.

16. What constitutes the skeleton?

17. In what respects does the body of a grasshopper
differ from the body of a man?

18. Name all the parts of the digestive system.

19. Where is the crop?

OOM SOR wor

22 INTRODUCTION TO ZOOLOGY.

20. Describe the teeth in the crop.

21. How many gastric ceca? What is their use?

22. Is the intestine straight?

23. Where are the ovaries?

24. What shape are the eggs?

25. In what are the eggs enclosed?

26. How many eggs did you find in the ovary?

27. Did you see any immature eggs?

28. How do the eggs escape from the body?

29. What is the oviduct?

30. What is the ovipositor? How is it used?

31. What are the urinary tubules?

32. What are the internal breathing organs?

33. Describe the structure of an air tube.

34. From what do the air tubes run?

35. Describe the branching of an air tube.

36. To what parts of the body do the air tubes run?

37. Is the grasshopper’s system of breathing as good
as ours?

38. Where is the nervous system?

39. Of what does the nervous system consist?

40. Is the nerve cord double or single?

41. How many ganglia in the body?

42. Where are the largest muscles?

Additional Facts About the Grasshopper.

The skeleton of the grasshopper consists of the
hard parts of the body, and these are on the outside.
It is therefore called an exoskeleton. It is composed
of a substance somewhat like horn, which is called
chitin. The teeth in the crop are composed of the
same material. The hard parts of the body are on
the outside, and growth cannot take place grad-
ually. Increase in size of the body cannot increase
the size of the hard skeleton. So, when a grasshopper
is growing up to full size, it sheds its skeleton four or

THE GRASSHOPPER. 23

fivetimes. This process is called molting, and is quite
easily observed. The grasshopper hangs head down-
ward from a twig, post, or some other support. The
skin, or skeleton, splits open on the back, and the
grasshopper comes out, leaving the old skeleton of
every part of its body ; eyes, antenne, legs, etc. The
process of molting requires about half an hour, and
after the process the legs are very weak and the body
very soft. Fora day or two the grasshopper grows
rapidly, and then ceases to grow until the next molt.

When a grasshopper is hatched from the egg, it
resembles somewhat the old one. In all its molting,
it still resembles the mature grasshopper. On this
account it is said to have an incomplete or direct
metamorphosis.

The metamorphosis of an insect is the series of
changes that it undergoes from the egg to the mature
form. q

The grasshopper breathes through spiracles which
open into the trachew, or air tubes through which air
is conveyed to all parts of the body. There is, then,
no need for blood to serve as a conveyer of air to the
tissues of the body, nor to carry carbon dioxide away
from the tissues. So we find that the blood in a
grasshopper is very small in quantity and is white in
color. It has no red corpuscles. There is a slender
tube lying along the back which contains some blood
and is called a heart. It is rather difficult to discover
in a dead specimen.

Each facet of the compound eye probably repre-
sents in some way a single eye. If all the facets of
the eye were covered up except one, the grasshopper
could still see with that one. The shape of the com-
pound eye is such that some of the facets are directed
upward, some downward, some forward, and some
backward. It would seem that the grasshopper is well
provided with means for seeing, but it is very doubtful

24 INTRODUCTION TO ZOOLOGY.

whether a grasshopper can see an object or not with a
compound eye. It can discern color and movement
very well, but these eyes can probably not define an
object to its sight. The ocelli probably enable the
grasshopper to see an object, but it must be one that
is very close to the eye if it can be seenatall. It
must be within half an inch or less of the eye.
Without any doubt, the grasshopper can feel. The
antenne and palpi are usually regarded as feeling
organs. It seems certain that the grasshopper can
hear, for it can make a noise, and it has an organ on the
abdomen that seems to have the structure of an ear.
An insect that makes a noise must be supposed to have
some means of hearing similar noises that other in-
sects of the same kind make. We judge from the
food that the grasshopper chooses that it can taste.
Whether it tastes with the tongue or palpi we are un-
able to say. It is probable that the sense of smell is
very different from ours. Our sense of smell is located
in the air passages of the nose. We should expect to
find the grasshopper’s nerves of smell reaching the
surface at the spiracles, but such does not seem to be
the case. It may be that the sense of smell, or what
corresponds to it, is located at the base of the antenne.
The food of the grasshopper consists of the leaves
of plants. The extent of injury grasshoppers do to
crops depends entirely upon their numbers. In 1874
and 1875 grasshoppers were so numerous that they
destroyed all the crops in the greater part of the states
of Kansas and Nebraska, and in some parts of Missouri,
Iowa, and adjoining states. The grasshopper that did
this injury is the kind known as Melanoplus spretus.
It is somewhat like the locust mentioned in the Bible.
Grasshoppers are prevented from becoming too
numerous by various enemies, or checks. One enemy
of the grasshopper is the silky locust mite. It is a very
bright red, eight-legged creature, and is often found

THE GRASSHOPPER. 25

clinging to the bodies of either the young or the old
grasshoppers. In the early spring, before grasshop-
per eggs are hatched, this mite finds the holes where
eggs of grasshoppers have been laid, and eats the eggs.
Hair worms are sometimes found in the intestines of
grasshoppers, and so, also, are the larve of some
Tachina flies. Such animals as the silky locust mite,
hair worm, and Tachina flies, that live upon the bodies
of other living animals, are called parasites. The
weather, no doubt, in some seasons, kills many grass-
hoppers, and they are subject, also, to contagious
fungous diseases. It usually happens that after a
season in which grasshoppers have been very numer-
ous, the following season will have very few.

The eggs of the grasshop-
per are laid in holes in the
ground. The female grass-
hopper digs with her oviposi-
tor a hole the length of the
abdomen, and deposits in it
amass of eggs, forty or fifty
in a bunch.

a, grasshoppers ovipositing; D,
egg case extracted; c,eggs; d, egg
case in the ground; c, egg case in
process of deposition; f, hole in
GRASSHOPPERS LAYING EGGS (AFTER RILEY) which eggs haye been laid.

In general, the grasshopper has a color that renders
it inconspicuous in the place where it usually lives.
Some grasshoppers, that like to live in the roads, are
dust-colored. Others, that are usually found among
dried grass, are mottled brown. Because the grass-
hopper is generally concealed or rendered inconspic-
uous by its color, it is said to be protectively colored.

Some grasshoppers live through the winter, but
most of them live not more than three months. They
die of old age before winter comes.

26 INTRODUCTION TO ZOOLOGY.

Names.

The grasshoppers that you have studied are indi-
viduals. Individuals that are much alike constitute
a species. Species that are much alike constitute a
genus. Genera that are much alike constitute a family.

We may make up a table like this :-—

Individual.
Species.
Genus.
Family.

All grasshoppers belong to the family Acridide.

In order that we shall know what kind of grass-
hopper or other animal or plant we are talking about,
they have been given names. A few of the most im-
portant rules for naming are here stated.

I. The name of every animal or plant consists of
two parts, the name of the genus and the name of the
species. The name of the genus should always be
written first, and should always begin with a capital
letter. The name of the species should usually begin
with a small letter.

Il. The name of every animal or plant should
be Latin, or have the Latin form. When this system
of naming was proposed, all scholars knew Latin.
It would be impossible for all scientific men to agree
upon German or English or French, or any other
living language. i

Ill. The name that is first given to an animal or
plant is the one by which it shall be known, if that
name is tenable. A name is not tenable if the same
name has been previously applied to some other
animal or plant. Usually, the name of the man
who first described the insect and gave it its name is
written after the name. This is called the Authority
and is often quite necessary to distinguish the insect.

CHAPTER II.

THE CRICKET.

1. Examine the cricket as you did the grasshopper.
See the body divisions, head, antennze, eyes, ocelli,
labrum, labium, labial palpi, mandibles, maxille,
maxillary palpi, thorax, wings, legs, coxa, femur,
tibia, tarsus, abdomen, and spiracles.

2. Find the ear, which is on the tibia of the fore leg.

3. Find the stylets, which are at the end of the.
abdomen.

4. If your specimen is a female, notice the long,
slender ovipositor, between the stylets. Of how many
parts is it composed? Why is this ovipositor so differ-
ent from that of the grasshopper?

5. Study the spiracles. How many?

6. If your specimen is a male, look on the under
side of the outer wing for a large cross-vein. Can
you find teeth upon it? With this the cricket makes
his chirping noise.

7. Can acricket fly? Some kinds have the inner
wings very small.

Additional Facts About the Cricket.

The cricket is black, or dark brown, and lives in
dark places, coming out only at night. It is therefore
protectively colored. The antennz are very much
longer and more slender than are the antenne of the
grasshopper, and probably in its dark crevice the
cricket must depend upon his sense of feeling more

27

28 INTRODUCTION TO ZOOLOGY.

than the grasshopper does. The stylets, also, are or-
gans for feeling.

The ovipositor is very long and slender. The eggs
are laid in acrevice or hole already provided. The
cricket does not make the hole.

The cricket belongs to the family Gryllide. The
family is named from the genus Gryllus, of which the
two most common species are abbreviatus, with short
inner wings, and luctuosus, with long wings.

Microscopic Objects.

The edges of the spiracles are
seen to be composed of two lips
hardened with chitin. From the
edges of the lips, fine hairs grow
inward, which serve to prevent
dust or other foreign particles en-
tering the trachex.

SPIRACLE OF CRICKET.

Behind the stomach will be
found a small spherical body, the
gizzard. This is composed of two
layers, the inner one of which has
six series of leaflike chitinous
teeth.

GIZZARD OF CRICKET,

THE KATYDID. 29

The cross- vein on the
outer wing of the male
cricket is provided with a
set of teeth, which, by rub-
bing over the vein of the
other wing, produces the
cricket’s chirp.

WING FILE OF MALE CRICKET.

THE KATYDID.

1. Examine the katydid as you did the grass-
hopper. See all the organs.

2. Where is the ear?

3. Find the apparatus with which he makes the
sound ‘‘ Katydid.”’

4. Find the ovipositor. Is it straight or curved?
Of how many parts is it composed?

Additional Facts.

The katydids are light green colored, like the leaves
among which they live. They are protectively colored.
The legs are more slender, and the whole body is more
loosely joined together than that of the grasshopper.
This may be associated with the fact that the katydid
does not fly so far nor so rapidly as the grasshopper does.

The eggs of the katydid are laid upon or in the
edges of leaves, or sometimes between the bark and
stem of a shrub or twig.

The katydid belongs to the family Locustidee.

30 INTRODUCTION TO ZOOLOGY.

THE WALKING STICK.

1. Find the parts on the walking stick that you
found on the grasshopper. Are any parts missing?

2. Can you find any ears? Has it any means of
making a noise?

3. The abdomen of the female is thicker than that
of the male. The male has a spine on the femur of
the hind leg that is much larger than the spine on the
female. Is your specimen a male or a female?

4, What enables the walking stick to escape from
its enemies?

Additional Facts.

The walking stick represents the family Phasmide.
The only species common throughout the United States
is Diapheromera femorata.

The walking stick feeds on the leaves of trees and
bushes. It resembles the twigs so closely that when
resting upon the bushes it is very difficult to see. This
resemblance of an animal to some other object is called
protective resemblance.

Make a table after the following form, showing the
differences between the grasshopper, cricket, katydid,
and walking stick.

Grass- A - Walkin;
hopper. Cricket. Katydid. Stick. g

Acridide. | Gryllide, | Locustidiw. | Phasmide.

Ear.... a
Locomotion ............ Wektaewts eiakeaes

THE WALKING STICK. 31

Make a table in the following form, stating the
resemblances concerning the eyes, antenne, etc., of
the grasshopper, cricket, katydid, and walking stick.

all have two compound eyes
all have one pair of antennz
all have two pairs of jaws
jaws move sideways

have three body divisions
three thoracic segments

Grasshopper two pairs of wings (except the walking stick)
Cricket three pairs of legs
Katy did segmented abdomen

Walking Stick | all lay eggs
jointed appendages
incomplete metamorphosis
external chitinous skeleton
white blood
double nerve cord and ganglia
breathe by spiracles

There are two other families which are very simi-
lar to the insects previously studied. These are the
Blattide, represented by the Cockroach, and the Man-
tide, represented by the praying Mantis. All these
families are so much alike that they are grouped
together, and the group is called an order. The name
of the order is Orthoptera. The name means straight
wings, and the order was named from the outer wings
of the grasshopper. The name is not a good one, for
the walking stick has no wings at all, but is so much
like the grasshopper in other respects that it must be
put into the same order. The Orthoptera all have
biting mouth parts and incomplete metamorphosis.

CHAPTER III.

THE BUTTERFLY.

Any butterfly will do for this study, but the large,
brownish red butterfly with black wing veins (Anosia
plexippus) is a good one.

1. Find the body divisions.

2. On the head, find the eyes, labial palpi, an-
tenn, and sucking tube. To what organs on the
grasshopper does the sucking tube correspond?
Are there any other mouth parts? Are there
ocelli?

3. Study the legs. Are all alike? Identify all
the parts. Of what use are the legs?

4, Study the wings. To what is each attached?
How are they held when at rest? Which side of
the wing is exposed to view when the butterfly is
resting?

5. Scrape some dust off the wings. This dust
consists of scales which cover the wings and the body.
Examine a piece of the wing with your lens. The
scales may be seen overlapping each other like the
shingles on a roof.

6. At the base of the fore wing, find an appendage
covered with scales or hair. This is the patagium, or
shoulder lapper.

7. Make a drawing of the veins of the wing. The
central cell, from which several veins seem to start, is
called the discal cell.

8. How many segments in the abdomen? Are
there spiracles? How many?

82

THE CATERPILLAR. 33

THE CATERPILLAR.

1. Can you distinguish any body divisions? Is the
head distinguishable from the rest of the body?

2. Are there antenne on the head? Eyes? Man-
dibles? Palpi?

3. How many segments behind the head? Are
there spiracles? How many?

4. How many legs do you find? What difference
in the legs?

5. The kind of legs in front are the true legs. On
what segments are they borne?

6. The kind of legs behind are false legs, or pro-
legs. On what segments are they borne? Examine
carefully the tip of each of the prolegs.

7. What changes would have to be made in the
body of a caterpillar in order to make a butterfly out
of it?

8. Describe the color, hairs, and anything else you
see on the caterpillar.

9. The caterpillar is the larva of a butterfly or
of a moth.

10. The butterfly or the moth has an indirect or
complete metamorphosis.

THE CHRYSALIS AND COCOON.

1. If the chrysalis and cocoon of the large moth,
Samia cecropia, can be obtained, it will serve for this
study very well. If not, any other chrysalis will do.

2. Study the shape and mode of attachment of the
cocoon. Draw.

3. Do you find a hole at one end of the cocoon?
Toward which end of the twig is the hole?

4. Cut open the cocoon along one side. Of how
many layers is it composed? How do the layers
differ?

34 INTRODUCTION TO ZOOLOGY.

5. The material of which the cocoon is composed
is silk. Silk originates as a liquid in some glands in
the caterpillar, which open near the maxillew. It is
drawn out ina fine thread which hardens when ex-
posed to the air.

6. Study the chrysalis. Note its size and shape.
Draw.

7. Can you distinguish body divisions? Abdom-
inal segments? Spiracles? Wings? Antenne?
Sucking tube?

8. Perhaps in the cocoon you can find the cast-off
skin of the caterpillar.

9. The chrysalis is the pupa of a butterfly or of a
moth. Butterflies do not make cocoons.

THE MOTH.

1. Study a moth as you did a butterfly. Note all
the differences you see in the antenne, size of the
body, position of the wings when at rest.

2. Make a table of differences between a butterfly
and a moth, according to the following form :—

BUTTERFLY. MOTH.
ATG OWNER fs coh hte vB cass EMRGS S|” disney eae 18h, SARA cusped a iSa eo oO Reeve are
Thickness of the body .......]............ dhs cassava arbre adits GICs, 3 Made
Position of the wings at rest.|..........00. eeepc eee eee te eee
) & £110) | K-pn diurnal nocturnal
COC GOB 5 ee 5 jours rem eateetnec rc ieaal| Sealy aerate a Sec atas. peeve) | “aycuG cenana, 41h core dveeeeal

Additional Facts.

In the growth of a butterfly, or of a moth, there
are four stages: egg, caterpillar, chrysalis, and butter-
fly or moth. The caterpillar is called the larva; the
chrysalis is called the pupa; and the mature butterfly
or moth is called the imago. This kind of metamor-

THE MOTH. 35D

phosis is called a complete metamorphosis, for the
stages are very distinct from each other. It is also
called indirect, because the butterfly or inoth reaches
its mature form by a roundabout way, through the
several stages.

Microscopic Object.

The color of the wings
depends upon the color of
the scales. Scales of several
different shapes may be
found upon the wing of a
butterfly.

SCALES OF CECROPIA MOTH.

The butterfly has sucking mouth parts. The suck-
ing tube is composed of two parts which are homol-
ogous to the maxille of the grasshopper. Two or-
gans are said to be homologous when they bear the
same relation to their respective bodies, no matter how
different the organs may be in appearance or use. In
this case, one pair of organs on the grasshopper has
been developed as a pair of jaws, and we call them
maxille. The same organs have been developed on
the butterfly as a sucking tube. It is this sameness
that constitutes the homology. We know that two
organs are homologous by their having the same posi-
tion or the same structure.

The labial palpi and the sucking tube are the only
mouth parts the butterfly has. Indications of the

36 INTRODUCTION TO ZOOLOGY.

other mouth parts may be found on the butterfly, but
these organs never become functional in the imago.
They are said to be vestigial. In the Samia cecropia,
and other moths of the family Bombycide, all the
mouth parts are rudimentary or vestigial. They are
unable to eat anything while in the imago state.
They do not live; they die. The Samia cecropia will
die within about five days after it comes from the
cocoon. Its eating has all been done by the caterpil-
lar. The only function of the imago is to lay eggs and
reproduce the species. We shall find many examples
of vestigial organs. They seem to be organs which are
retrograding, or having once been functional in the
history of the species, have ceased to be so.

‘Anosia plexippus furnishes a good example of the
form of protective coloration that is called mimicry.
The butterfly itself is not concealed by its color. It is
very conspicuous. But it is quite distasteful to birds
and other insect-eating animals. Its conspicuousness
is an advantage to it, for when the birds know what
it is they will let it alone.

But there is another butterfly, Basilarchia archip-
pus, which closely resembles the plexippus in color.
It can be distinguished by a black streak across the
hind wing. This butterfly is not at all distasteful to
birds ; but birds, being deceived by its resemblance to
plexippus, seldom catch it. The archippus is said to
resemble, or imitate, or mimic the plexippus. Struc-
turally, the two butterflies are very different, and no
other species of the genus Basilarchia is colored like
this one. Numerous examples of mimicry may be
found among insects.

All silk of commerce is produced by the caterpillar
of the silk worm (Bombyx mori). The cocoon of the
Samia cecropia is larger and contains more silk, but
it cannot be reeled, in consequence of being fastened to
a twig or some other solid support.

THE BEETLE. 37

Among the moths and butterflies are found some
very injurious insects. The injuries are all done by
the larve. Among them we may mention the clothes
moth, cotton worm, bollworm, tobacco moth, tomato
moth, tent caterpillar, codling moth, and gypsy moth.
The codling moth is the moth whose larva appears as
a white worminthecoreof anapple. The gypsy moth
is very destructive to forest trees in Massachusetts.

Butterflies and moths belong to the order Lepi-
doptera. The name means scaly wings. All the
Lepidoptera have sucking mouth parts and complete
metamorphosis.

THE BEETLE.

1. Identify the body divisions.

2. Find the eyes, antenne, labium, labial palpi,
mandibles.

3. Identify the parts of the leg. An extra joint,
between the coxa and the femur, willbe seen. This is
called the trochanter. How many segments in the
tarsus? Do all the tarsi have the same number?

4. Study the wing. How does the fore wing
differ from the hind wing? The fore wings are here
called elytra. What is their use?

5. How does the hind wing fold up?

6. Draw the wings, both open and closed.

7. How many segments in the abdomen? Do you
find spiracles? How many?

8. Make a drawing of the larva of the beetle.
Does the beetle have a complete or an incomplete
metamorphosis?

9. Draw a full page ventral view of a beetle, show-
ing all the parts.

Additional Facts.

The beetle belongs to the order Coleoptera. This
is one of the largest orders of insects. The name

38 INTRODUCTION TO ZOOLOGY.

means sheath ‘wings, and it is so called from the
character of the fore wings. There are probably
25,000 species of beetles. All have biting mouth parts
and complete metamorphosis.

Among the beetles are many injurious insects.
We may mention the wire worms, which are larvee of
click beetles, and the curculios, the wood borer, the
carpet beetle, and the Dermestids, or fur beetles.

Beetles are found almost everywhere. Some live
in the water, some in the ground, some in decayed
wood, and some on leaves. Some are predaceous and
prey upon other insects.

THE GIANT WATER BUG.

Find the body divisions.

Find the compound eyes. Are there ocelli?
Find the antenne. Draw.

Find the sucking tube. Is it segmented? How
many segments? ‘To what is it homologous?

5. In a groove on the upper side of the sucking
tube, find a hair-like organ. Of how many parts is it
composed? To what must these parts be homologous?

6. Find a pointed flap lying on top of the groove
which conceals the hair-like organ, or punctorial
bristle. From its position, to what must it be homol-
ogous?

7. Study the wings. What peculiarity has the
front pair? Draw.

8. Notice how the wings lock together when folded
on the back. Find the little knob fitting into a groove
on the edge of the thorax, that holds the wings down
to the body. See how the fore and hind wings are
held together when the wings are spread. Draw.

9. Identify the parts of the legs. How does the
hind leg differ from the fore leg? Is the femur of the
fore leg grooved or smooth?

gobo

THE CICADA. 39

10. What peculiarity has the prothorax?

11. Study the abdomen. How many segments?
Do you find any spiracles? Where?

12. Cut off the wings and find the nerve cord.
How does the nervous system differ from that of the
grasshopper?

13. Look at the larva and say whether the giant
water bug has a direct or an indirect metamorphosis.

Additional Facts About the Giant Water Bug.

The giant water bug lives in ponds, and flies

around at night. It is attracted in great numbers to
electric lights, and is sometimes called the electric-

light bug. There are two kinds, the Belostoma
americanum, in which the femur of the fore leg is
grooved to receive the tibia, and Benacus griseus, in
which the front femur is not grooved.

The giant water bug is quite destructive to min-
nows and young fish, piercing them with its beak.
Parasites are frequently found on giant water bugs,
one of the most commen forms being Hydrachna
belostome.

A smaller insect, Zaitha fluminea, much like the
giant water bug, and living in the same situations,
may be used for this study. The squash bug is also
very good.

THE CICADA.

1. Identify the body divisions.

2. Study the eyes, ocelli, antenne.

3. Examine the mouth parts. See the punctorial
bristle. Of how many parts is it composed?

4. Notice the wings. How do they differ from the
wings of the giant water bug?

5. Study the legs. How does the first pair differ
from the other legs?

40 INTRODUCTION TO ZOOLOGY.

6. If your specimen is a male, note the air sac in
each side of the dorsal surface of the abdomen. See
the thin plates on the ventral side of the abdomen,
which are used in producing the sound.

7. If your specimen is a female, study the oviposi-
tor carefully.

8. Draw the entire insect.

Additional Facts About the Cicada.

Either the seventeen year Cicada, or the common
harvest fly, may be used in making this study. There
are very few insects that live longer than the sev-
enteen year cicada. It lives under the ground as
a larva or pupa for seventeen years, then suddenly
makes its appearance in May or June, transforms to
the imago stage, lives for three or four weeks, lays its
eggs, and dies. The eggs are laid in a groove cut by
the female in the young twigs of trees. The eggs
hatch and the larve drop to the ground, in which they
disappear and are seen no more for seventeen years.
The twigs in which the eggs are laid frequently die
from the injury received, and as a result much dam-
age is done, especially to fruit trees. There are in this
country about twenty-three broods of the seventeen
year locusts, so that at least one brood is likely to
appear somewhere in the United States every year.
There is also a thirteen-year form, of which several
small broods exist in the United States. Thecommon
harvest fly, or dry fly, Cicada pruinosa, lives only
two years.

The Cicadas are noticeable for the very loud noise
they make. Under ordinary conditions, the song of
a single Cicada can be heard for at least a mile.

The Cicada and the giant water bug represent two
divisions of the order Hemiptera. All the insects of
this order have the sucking mouth parts and incom-

THE CICADA. 41

plete metamorphosis. The pupa of the Cicada is
very unlike the imago, but as is the case with
the pupa of other Hemiptera, it has no period of in-
activity.

The name Hemiptera means half wings, and refers
to the texture of the different parts of the fore wings
on the giant water bug, or still better, the squash bug.
The name for the order is not a good one, for some of
the insects of this order have no wings; in some, as in
the Cicada, the wings are uniform in texture through-
out. The order is now commonly separated into two
divisions: Heteroptera, represented by the giant water
bug; and Homoptera, represented by the Cicada.

Among the Hemiptera we. find some of the
strangest forms known among insects. Especially
is this true of the tree hoppers, the wheel bug, and
the water scorpion.

We find also among the Hemiptera some of the
most destructive insects. In some years the chinch
bug has destroyed crops, principally of wheat and
corn, whose value would amount to many millions of
dollars. It produces the injury by piercing the stalk
of the plant with the beak and sucking out the
juices.

Among the plant lice, especially, we find examples
of a method of reproduction that is quite unusual
among animals so highly organized. In nearly all
animals, the individuals are male and female. Ordi-
narily, the eggs of the female will not hatch, or pro-
duce young, unless they are fertilized by the male.
But we find that several generations of plant lice may
be produced in one season without fertilization by
any male. This process of reproduction without
fertilization by a male is called Parthenogenesis.
Generally, at the close of a summer a sexual genera-
tion is produced and fertilization occurs in the

ordinary way.

42 INTRODUCTION TO ZOOLOGY.

THE HOUSE FLY.

1. Identify the body divisions.

2. On the head, find the eyes, ocelli, antennie.
Draw the antenne.

3. Examine the so-called ‘‘ tongue,’’ or proboscis.
Identify the palpi, the labelle, or large flap at the
tip, the sheath, and the lancets within the sheath.

4. Identify the segments of the leg. Study the
foot carefully. Draw.

5. Find the wings. How many? See the back-
ward extension of the wing, which is called the alula,
or winglet. Study and draw the wing carefully.

6. Back of the wing, find on each side a knob
borne on a stalk. These knobs are known as the
balancers. Judging from their position, to what are
they homologous? —

7. Are there spiracles on the thorax?

8. How many segments has the abdomen? How
many spiracles do you find?

9. The larva is called a maggot. Where can it be
found? What kind of metamorphosis has the fly?

Microscopic Objects.

With the exception of the max-
illary palpi, the mouth parts of
the fly are modified into a pro-
boscis which constitutes a suck-
ing and piercing organ. When
not in use, it is folded up under
the head.

PROBOSCLTS OF FLY,

THE HOUSE FLY. 43

The labelle consist of a
mass of tissue through
which run_ spirally-coiled
rods radiating from a horse-
shoe-shaped rim. The la-
belle are probably homol-
ogous to the labial palpi,
and the palpi are maxillary
pilpi.

LABELL2 OF HOUSE FLY’'S PROBOSCIS.

The horseshoe-shaped rim seems to constitute the
end of the sheath, and through its opening the lancets
work. The sheath is homologous to the labiuin.

The lancets are enclosed in
the sheath, and are homol-
ogous to the maxilla. They
are moved up and down by
two chitinous rods to which
muscles are attached.

LANCETS AND PALPI OF HOUSE FLY,
(Labelle removed.)
The lancets pierce the skin of an animal, and the
labellee and sheath constitute a sucking organ by
which the blood is drawn from the puncture.

44 INTRODUCTION TO ZOOLOGY.

The foot consists of two
pads thickly beset with
minute hairs, and two
hooks. No thoroughly sat-
isfactory explanation has
been given of how a fly
sticks to a vertical surface
of glass.

FOOT OF FLY.

The wing of any insect is
composed of veins, and
spaces bounded by veins.
These spaces are called cells.
The large vein forming the
front margin of the wing is
called the costal vein. The
vein marked 1 is the auxili-
ary vein; 2,3, 4,5, and6 are
the first, second, third,
fourth, and fifth longitudi-
nal veins. The short cross-

vein between 4 and Sis the
middle transverse vein; the
short vein between 5 and 6

is the hinder transverse WING OF FLY.

vein. The cells A, B, and

C are called the first, second, and third costal cells; D is the mar-
ginal cell; E is the sub-marginal cell; F, K, and TL are the first,
second, and third posterior cells; G is the discal cell; H is the first,
or large, basal cell. The cells and veins of the wing are of the

greatest importance in determining the families and species of
flies. The veins of a fly’s wing may be homologized with the veins

of the wing of almost any other insect.

THE HOUSE FLY. 45

Additional Facts About Flies.

The house fly belongs to the order Diptera. The
name means two wings. The balancers represent
another pair of wings in a rudimentary condition, so
that flies really have the same number of wings that
other insects do.

All diptera have sucking mouth parts and a com-
plete metamorphosis, although in some members
of the order, as the mosquito, the pupa is active.
The larva of a fly is called a maggot. It is usually
found in decaying animal matter. The mosquito
lays its eggs in a bunch, which floats on the sur-
face of the water. The egg hatches into a wiggler,
which swims in the water, coming to the surface to
breathe. It breathes through air tubes opening
in the tail. The pupa is quite different from the
larva, being a club-headed wiggler, living also in
the water.

Some flies lay their eggs in the tissues of plants.
The tissues then swell up around the egg, making a
gall in which the larva and pupa live and undergo
their transformations. These flies are called gall
gnats.

Among the Diptera we find some of the most
annoying insects. House flies, cow flies, bot flies,
mosquitoes, and gnats, may be mentioned. The
Hessian fly is exceedingly injurious to wheat, its
injuries entailing a loss of many thousands of
dollars every year to the farmers of the United
States.

It is among the Diptera that we find the
greatest number of examples of protective mim-
icry. There are flies that closely resemble bees,
bumblebees, wasps, hornets. In many cases the re-
semblance is so close that experienced collectors are

deceived.

46 INTRODUCTION TO ZOOLOGY.

THE DRAGON FLY.

1. Identify the body divisions.

2. Study the eyes, antenne, mandibles, maxilla,
palpi.

3. Study the wings. Note the pterostigma, near
the tip, and the short cross-vein, the nodus, near the
~ base. Count the cells and long veins. Draw.

4. Identify the parts of the leg.

5. How many segments in the abdomen? Do you
find spiracles? Is there any sting?

6. Draw the larva. What kind of metamorphosis
has the dragon fly?

Additional Facts About the Dragon Fly.

The dragon fly belongs to the Linnean order
Neuroptera. The name means nerve wings, and is
given because of the great number of veins in the
wings. In some parts of the country it is called
devil’s darning-needle, and is said to sew up the ears
of bad children; but the devil has a proprietary
interest in so many of these insects that the name is
not sufficiently distinctive. ‘It is also called snake
doctor, from the fact that it is frequently seen hover-
ing over the body of a dead snake, and so some
people suppose it is restoring the dead snake to life.
Really, it is engaged in catching the flies that are
attracted 1o the body of the dead snake. A better
name is mosquito hawk, for it is among insects what
a hawk is among birds. It is probably the strong-
est and swiftest flier among insects. Whether it is
a larva, @ pupa, or an imago, it is the enemy of the
mosquito.

The eggs are laid in the water, and there the dragon
fly undergoes all its transformations until it reaches
the imago stage. There are two kinds of dragon flies.

™HE BUMBLEBEE. AT

One is represented by the Agrionide, in which the
wings of the imago fold together on the back, and
whose larva breathes through thin leaf-like gills at the
tail. The other kind is represented by the Libel-
lulide, whose wings do not fold and whose larva looks
something like the larva of the giant water bug. The
metamorphosis is complete, although the pupa has
no resting stage.

This old order, Neuroptera of Linnzus, has been
broken up into five or six orders by more recent wri-
ters. It is probably better to call the order to which
the dragon fly belongs Odonata.

THE BUMBLEBEE.

1. Find the body divisions. How many segments
in the abdomen? How is the abdomen joined to the
thorax? Can you find any indications of extra seg-
ments on the thorax?

2. Describe and draw the eyes, ocelli, mandibles,
antennze. How many segments in the antenne?

3. The other mouth parts are the tongue, maxille,
and labial palpi. The tongue is the hairy organ.
The labial palpi terminate in two short segments.
Can you find any trace of rudimentary maxillary
palpi?

4. Study the wings. See how the fore and hind
wings fasten together. Examine the front edge
of the hind wing for hooks that fasten the wings
together.

5. Homologize the parts of the leg. See the flat
‘pollen basket ’’ on the tibia of the hind leg. Itisa
smooth, shiny surface surrounded by stiff hairs. Is
any pollen sticking to it?

6. What is honey? Where do the bees get it?
What is pollen? Where obtained? For what used?
What is wax? How obtained?

48 INTRODUCTION TO ZOOLOGY.

7. Study the sting. The sting consists of a sheath
and tio lancets connected with a poison bag. At the
end of the abdomen, find two palpi.

8. What is a queen? A drone? A worker? Of
what use is the bumblebee’s color?

THE WASP, OR HORNET.

1. Look onthe wasp for the same things you found
on the bumblebee, noting all differences.

2. Note, especially, the tongue. Draw.

3. Draw the larva. The pupa. What kind of
metamorphosis has the wasp?

4. The sting is more easily studied than that of
the bee. Draw.

5. Study and describe the wasp’s nest. The mud
dauber’s nest.

Microscopic Objects.

The tongue of the bee is
Yr a slender, hairy organ. It
Pose . J rx .
4 consists of a slender carti-
. 4 laginous rod and a muscular

4;

\\| sheath, The sheath is
merely folded around the
rod, and is not joined at the
edves.

The labial palpi are recog-
nized by being segmented.
Two short segments at the

Me tip, one longer segment
next, and then a still longer
segment constituting the

Pawnee Soe 1 ete principal part of the palpus.

TONGUE, MAXILL#, AND PALPI The maxilla are broader

OF HONKY BEB, fe

and flatter than the palpi.

Near the bend of the maxille can be seen the rudiments of the
maxillary palpi,

THE WASP, OR HORNET

TONGUE OF WASP.

The sting of a wasp or bee con-
sists of a sheath and two lancets.
The lancets are barbed at the tips
and are moved up and down by
muscles in the wound that the
sheath makes. Near the sting are
two palpi by which the wasp is
able to feel what it is stinging.

HOOKS ON HIND WING OF WASP.

49

The tongue of the wasp is very

different from that of the bee.
It is muscular, forked, and cov-
ered with hairs.

STING OF WASP.

There are about twenty hooks
on the front edge of the hind
wing. These hook over a vein on
the fore wing, and the two wings
act together as one.

50 INTRODUCTION TO ZOOLOGY.

Additional Facts About Bees, Ants, and Wasps.

Ants, bees, and wasps belong to the order Hy-
menoptera. The name means membrane wings, and is
applied to those insects because the wings are mostly
membrane, having very few veins. The metamor-
phosis iscomplete, the larva and pupa both being help-
less, living in a cell and being attended by the mature
insects until all their transformations are completed.

They must be classed with the insects having
sucking mouth parts, although the mandibles are
used for biting also. The social organization is very
complex. Among the bumblebees and hive bees there
are three kinds of individuals : the queens, or females ;
the drones, or males; and the workers, which are
sometimes called neuters but really are undeveloped
females. .The queens lay the eggs. The presence of
the drones is necessary, to fertilize the eggs; and the
workers, which constitute the most numerous class,
attend to storing honey, making wax, and feeding the
young bees.

Honey is obtained from flowers. Nectar, when it
is gathered, contains more water, more essential oils,
and less formic acid, than honey. When a cell is
filled with honey, formic acid is added to the honey
from glands in the head, and the cell is capped over
with wax. Formic acid is the same poison that is
ejected by the sting, and it acts as a preservative of
the honey. Honey that is taken before the cells are
capped over will usually ferment and spoil. Pollen is
the pollen of the flower, and is gathered to feed the
young bees. Wax, from which honeycomb is made,
is secreted by the bees from glands which open on the
abdomen. When making wax, some of the bees re-
main stationary in the hive and are fed honey by other
bees. They eat about twenty-one pounds of honey for
svery pound of wax they secrete. The workers take

BEES, ANTS, AND WASPS. 51

the wax away as fast as it is secreted and build it up
into honeycomb. The sting serves. as a means of de-
fense. The barbs on the lancets account for the fact
that the sting is so frequently found in the wound, and
the fact that the poison is an acid indicates that am-
monia or a solution of soda in water, applied quickly,
is a remedy, because either of these will neutralize an
acid.

The bumblebee gathers honey especially from red
clover and from thistles. The tongue of the hive
bee is too short for the tubes of these flowers. When
a bumblebee visits many flowers of clover in succes-
sion, some of the pollen of one flower, by sticking to
the hairy tongue, is brought into contact with the
stigma of another flower. In this way bumblebees
bring about cross fertilization of the flowers. This
cross fertilization is necessary to the continuous pro-
duction of red clover. Without it, very little seed
will be produced. Frequently two crops of clover are
produced in one year. The first crop is usually cut
for hay. It has very little seed, as there are few
bumblebees so early in the year. The second crop
has an abundance of seed, as there are many bumble-
bees late in the season.

When clover was introduced into Australia, it pro-
duced no seed, and the fields had to be seeded every
second year with imported seed. But bumblebees were
introduced, and now the clover produces plenty of seed.

Other insects besides bees aid in the cross fertiliza-
tion of plants. Wasps, butterflies, moths, and flies of
certain families, fertilize different kinds of flowers.

The bumblebee is colored yellow and black, a very
conspicuous combination, and it is frequently seen on
clover blossoms, which furnish a contrast that is even
more conspicuous. ‘The bee, then, is not concealed by
its color. The color of the ‘bee is said to be a warn-
ing color. It is a danger signal to other animals.

52 INTRODUCTION TO ZOOLOGY.

It is an advantage to the bumblebee to be thus col-
ored, for other animals, aware of its stinging power,
will let the bee alone if they know where it is.

The drone bumblebee has no sting. In some
species, however, it is even more yellow and flaunts
a more conspicuous danger signal than the stinging
bumblebee. The conditions of mimicry are found in
the drone bumblebees.

Wasps are of two kinds, the social and the solitary.
The social wasps have the same three kinds of indi-
viduals that are found among the bees. They build
nests like honeycomb, with six-sided cells, out of
paper. The true social wasps build these combs in
sheltered places, and put no covering over them.
The hornet builds the same kind of paper nest,
but surrounds the nest with a paper envelope. The
paper is made from disintegrated woody fiber, ob-
tained from weather-beaten boards or sticks of wood.
The young are reared in these cells. The wasps
themselves eat vegetable food, but they feed the
young upon the bodies of other insects.

The solitary wasps either dig holes in the ground
or build nests of mud which they place in some shel-
tered position. As soon as a cell is built, the wasp
provisions it with the bodies of other animals, such
as spiders, caterpillars, cicadas, etc. Each kind of
wasp selects a particular kind of animal with which
to provision its nest. The wasp, having found a
spider, for example, stings it in a ganglion of the
nervous system on the ventral side of the body. If
a caterpillar is the object of attention, the sting is
thrust into nine or ten of the ganglia. The slender
pedicel of the wasp, by which the abdomen is attached
to the thorax, enables it to reach around to the under
side of the spider or the caterpillar and sting it in the
proper place. The effect of this sting is to. paralyze
the victim, not to killit. It is then carried to the nest

BEES, ANTS, AND WASPS. 53

and packed in the cell. Sometimes ten or fifteen spi-
ders, all paralyzed, are packed into one cell. Even if
they should die, as they must after awhile, the preserva-
tive effect of the formic acid is sufficient to keep the
bedies from decay. The egg is then laid, and the nest
sealed up. The wasp larva hatches, eats the food
prepared in advance for it, and finally breaks out of
its mud cell amature wasp. The solitary wasps have
only two kinds of individuals, male and female.

In some respects, the ants represent the highest
degree of insect intelligence. Not only have they the
same three classes in a colony that the bees and wasps
have, but in some cases there is a fourth class, the
soldiers, whose only business is to fight, defending the
nest or attacking other colonies. It has long been
known that certain kinds of ants make forays upon
the nests of other kinds, whose larvee they carry off
and rear in their own nests to serve as slaves. It is
also known that certain ants keep in their nests and
care for certain plant lice which secrete a sweet liquid
much appreciated by the ants. Such plant lice are
called ants’ cows. Other insects are found in ants’
nests, and we are unable to account for their presence
except by likening them to our own domestic animals.

The agricultural ant of Texas is known to clear
off a piece of ground from 6 to 8 feet in diameter,
keep down the weeds, allowing a kind of grass known
as ant rice to grow, gather the grains of rice when
they are ripe, store them away in granaries, and bring
them out to dry when they get wet. It has not been
seen to plant thé rice, but some people believe that it
does so.

The leaf-cutting ant of Central America is known
to cut pieces of leaves and carry them into a nest,
where they ferment and form a hotbed in which
springs up a kind of fungus that furnishes the princi-
pal food of the ants.

54 INTRODUCTION TO ZOOLOGY.

These are some of the facts that are relied upon by
some to show that in amount of intelligence ants
rank next to man.

Orders of Insects.

Copy into your notebook, spell, and pronounce, the
following words :—

Or thop'te ra Te mip’te ra
Lep i ddp'te ra Dip’te ra
Co le op'te ra Hy me nop’te ra

Neu rop’te ra
These seven orders are the orders of insects as
established by Linnzeus. Recent entomologists make
the following divisions :—
Thys a nii'ra—spring tails
Eph e mér’ i da—may flies
Od o na&’ ta—dragon flies
Ple cép’te ra—stone flies
Cor ro dén’tia—book lice
I sép'te ra—white ants
Mal léph'a ga—bird lice
Ku plex dp'te ra-—earwigs
Or thop'te ra—grasshoppers
Phy sdp’o da—thrips
He mip’te ra—giant water bugs
Neu rép‘te ra—corydalis, ant lions
Me cdp’te ra—scorpion flies
Tri ehdp'te ra—caddice flies
Lep i dop'te ra—bntterflies, etc.
Dip'te ra—house flies, ete.
Siph o nip'te ra—fleas
Co le op'te ra—beetles
IIy me nép’te ra—bees, wasps, ants

ORDERS OF INSECTS. rare)

Make a table of differences among the seven orders
of insects, according to the following form :—

: : 2 i od
me * 5 —s
ox s a ne rs] a) ou
25 ai 5 Be |@5/o5/28
ae oS 2s oe ge | ss l\o=
25 83 Se 2 |Ssles|23
= pet} os om Soles D
as so [can 3 ei a \ee
eas Bo S Be Af lanlee
o~ A a Aa) at ae
oO
WAR BS ie. scciciicge sin: wtegebinete| Seoaesietancan sell caidabeauecin| wedbaannedi[adenmaleteeis[esiaibs
Mouth parts...... biting .|.... .... sucking |......)......
Metamorphosis .. |........... Bits ie Saieh lsstitehende eg fowigeeal ates
Larva........ eee nymph|caterpillar |........... sauprg ees [ancbete | eaten
PUp@isiss wise snce ACLIVE .| ice swersirnesse: inactive]............[eeeceepeeeee

Make a table of resemblances among the seven
orders of insects, after the following form :—

2 compound eyes
1 pair of antepnze
2 pairs of jaws

2 pairs of wings

Grasshopper 3 pairs of legs
House fly jointed appendages
Butterfl ‘

MA segmented abdomen
Beetle 3 body divisions
Giant water bug 17 body segments
Dragon fly breathe by spiracles
Bumblebee

reproduce by eggs

double nerve cord and ganglia
chitinous exoskeleton

white blood

Compare this table with the one on page 31.
What characters found in that table are omitted in
this one?

Orders which are alike constitute a class. These
seven orders agree in the many characteristics ex-
pressed in the table of resemblances. They constitute
aclass. The name of this class is Insecta. An in-
sect, then, is an animal having all the characteristics

56 INTRODUCTION TO ZOOLOGY.

mentioned in the table of resemblances. This is not
a good definition, but it will do until we can make a
better one. When we say of a thing, ‘‘ This is an
insect,’’ we mean that it possesses all the character-
istics mentioned in this table of resemblances.

Logical Definition.

A Lepidopter is an insect having scaly wings, sucking
mouth parts, complete metamorphosis, whose larva is
called a caterpillar, and whose pupa is inactive. This is
called a logical definition. Its predicate noun is the
name of the class to which the order belongs, and the
modifying characteristics are the differences which
separate the order Lepidoptera from the other orders
of the class Insecta. Now, from your table of differ-
ences, make a similar definition of each of the other
orders of the same class.

To the Teacher.

The purpose of making these tables of resemblances and differ-
ences is to train the mind in its power of discrimination, compari-
son, generalization, and logical definition. Tle tables should be.
made hy the pupils,"as far as possible without reference to those in
the book, which are inserted merely to show how to make such
tables and how to use them.

Review Topics on Insects.

1. Name the seven orders of insects. Give examples
of each.

2. What is meant by metamorphosis?

3. Name four stages in the metamorphosis of insects.

4. What is molting?

5. Show the necessity for molting.

6. Describe a compound eye.

7. What are ocelli?

8. What are antennse?

REVIEW TOPICS ON INSECTS. 57

Tue Dragon Fty.

. Where does a dragon fly live?

. Where does it lay its eggs?

. Describe the larva.

. What mouth parts has a dragon fly?

. What kind of wings has a dragon fly?
. What is the pterostigma? The nodus?
. How many segments in the abdomen?

What does a dragon fly eat?

THe Grant WatTER Bua.

. To what order does a giant water bug belong?
. What kind of antennz has it?
. Describe the mouth parts. To what is each

homologous?

. Tell how the wings fasten.

. Describe the wings

. What peculiarity have the fore legs?
. What peculiarity have the hind legs?

What is peculiar about the nerve cord?

Tue House Fty.

. Describe the antenne.

Describe the eyes.

Describe the mouth parts. Indicate the homol-
ogies.

Where are the lancets? Of what use are they?

Of what use are the palpi?

. Describe the wings.
. What are the balancers? The winglets?

Describe the foot.

. Where are the eggs laid?

What other insects belong to the same order as
the house fly?

. What is the larva called?

58

INTRODUCTION TO ZOOLOGY.

Tue Beerie.

. Describe the antenne.

. Describe the mouth parts.

. Name all the parts of the leg.
. Describe the wings.

What are the elytra?

. How do the inner wings fold?
. Where are the spiracles?

. Describe the metamorphosis.
. What is the larva called?

Tue ButterRrty.

. What mouth parts has the butterfly?

. To what is the sucking tube homologous?

. Describe the wings.

. Describe the legs.

. Describe the metamorphosis.

. What is the larva called? The pupa?

. What is a cocoon?

. Tell what you know of the mouth parts of Cecropia.
. State five differences between butterflies and

moths.
Tue BUMBLEBEE.

. Describe the antenne.

. Describe the eyes.

. Tell what you can of the mandibles.
. Describe the other mouth parts.

Describe the wings.
Describe the legs.

. Describe the sting.

. What is the use of the sting?

. What is pollen? Wax? Honey?

. Tell of the social organization of bees.
. Describe the metamorphosis.

. Tell of the nests of paper wasps.

GENERAL CONSIDERATIONS ABOUT INSECTS. 59

66. Tell of the nest habits of mud wasps.
67. Discuss the intelligence of ants.

GENERAL.

68. Tell how an insect breathes.

69. What is meant by homologous parts?

70. What are vestigial organs?

71. What is protective coloration?

72. What is mimicry? Give examples.

73. How does the resemblance to Anosia protect
Basilarchia?

74. Of what is the skeleton of an insect composed?
How is it joined together?

75. Describe the nervous system.

76. What senses and sense organs have insects?

Some General Considerations About Insects.

There are about 250,000 species of insects already
known and described, and these are perhaps not more
than one-tenth of the species that exist. With the
probable exception of some classes of Protozoa, the
insects constitute the largest class of animals, both in
individuals and in species. Some insects are useful
to man. Shellac, cochineal, gall nuts, silk, beeswax,
and honey, are produced by them. The greatest
benefit, however, is derived from their assistance in
fertilizing plants.

Insects do much injury to mankind. Besides the
personal discomforts arising from such insects as flies,
mosquitoes, etc., the injury that insects do to crops in
the United States each year is very great. Mr. Riley
once estimated it at $300,000,000 per year.

The study of insects is called Entomology. In
studying insects, it is quite helpful to collect and pre-
serve them. An insect net is useful for collecting
many kinds of insects. The net should be about

60 INTRODUCTION TO ZOOLOGY.

eighteen inches deep, and may be made of India linen,
cheese cloth, bobinet, Swiss, or mosquito bar. For a
handle, fasten a stick like a broom handle to a hoop
about ten inches in diameter made of stout wire. When
an insect is captured, it is killed by dropping it into a
cyanide bottle. A cyanide bottle may be made from
any wide-mouthed bottle. In the bottom of the bottle
is placed about half an ounce of potassium cyanide,
which is a most deadly poison. This is covered with
sawdust well shaken down, over which some plaster
of Paris mixed with water is then poured until a
smooth surface is obtained. The bottle shouid be
left open until the plaster of Paris is dry. It should
then be stopped up, when the fumes of the cyanide,
rising through the porous plaster of Paris, will fill the
bottle, killing any insect that may be dropped into it.

After an insect is killed, it shouldbe pinned. The
pins used for this purpose are insect pins, which are
long, slender, very sharp-pointed, and have round
heads. Beetles are pinned through the right elytron.

The wings of butterflies and moths should be spread
out and held in position on a setting board until they
becomedry. A setting board is a board with a groove
in the middle to receive the body of the insect while
the wings lie flat on the side. The wings should be
drawn forward until the hind edges of the fore wings
are in a straight line.

A good book for the study of insects is Comstock’s
Manual of Entomology. Much valuable information
about insects may be found in the United States
Agricultural Reports and in the reports of the various
state entomologists. There is no one book that will
enable one to determine the species of every insect he
may find, nor even all the species of any one order.
A series of tables for the determination of the family
to which an insect belongs may be found at the back
of this book.

CHAPTER IV.

THE SPIDER.

1. How many body divisions? What may they be
called?

2. How many legs? To what are they attached?
How many segments in each leg? Homologize the
parts with the segments of the leg of the grass-
hopper. If you find an extra segment, it may be called
patella.

38. Which pair of legs-is the longest? Examine
the foot. Draw.

4. Find the eyes. How many? Draw.

5. Find the mandibles, with their poison fangs.
Draw.

6. Find the maxille. See the palpi. If the
palpi are swollen, it indicates a male. Are there
antenne?

7. At the tip of the abdomen, on the under side,
note the spinnerets. How many? Of what is each
composed ?

8. Near the base of the abdomen on the ventral
side of the female, find a hollow, curved tube, the
epigynum. Draw.

9. Near the epigynum, find on each side an open-
ing into the breathing organs, which may be called
air gills, or lung sacs.

THE DADDY LONGLEGS.

1. Identify the body divisions.
2. Where are the eyes? How many? What kind?
61

62 INTRODUCTION TO ZOOLOGY.

3. Identify the mouth parts. Draw one of each
pair.

4. How many legs? To what attached? Which
is the longest pair? How many segments in each?

5. Examine the foot. How can such slender legs
be adapted to this animal’s habits of life?

6. How many segments in the abdomen? Do you
find the means of breathing?

7. What kind of food does this animal eat? How
does it get food? How can it escape from its
enemies?

8. Of the animals that you have studied, which
one most nearly resembles the daddy longlegs?

9. Make a table of differences between the spider
and the daddy longlegs.

Additional Facts About the Spider and the Daddy
Longlegs.

The spider and the daddy longlegs are taken to
represent the class Arachnida. The spider belongs
to one order, the Araneina, and the daddy longlegs to
another order, the Phalangidea.

The daddy longlegs catches small insects which it
finds on various kinds of clustered flowers, or in other
places. Its favorite method of hunting is to run
about over the tops of thickly clustered shrubs or
weeds. Clumps of Symphoricarpus, or wolf-berry,
are favorite localities. For this habit, the long legs
and small body are admirably adapted.

Spiders are provided with a large fang on each
mandible, which folds up when not in use. It is hol-
low and is connected with a gland in the head. It is
called a poison fang, and the spider is generally sup-
posed to be a very poisonous creature. The writer
has caught hundreds of spiders with the naked hand,
and has been bitten but twice, by two particularly

THE CENTIPEDE. 63

vicious looking spiders. In neither case was there
any indication of a poisonous effect. Such is the testi-
mony also of almost every other experimenter with
spiders.

Some spiders spin webs. The web is of silk, and
comes out as a liquid from numerous tubes which
constitute the spinnerets. It hardens upon exposure
to the air. There seems little probability of making
use of spider web in a commercial way, although the
French government is making elaborate experiments
in regard toit. Hach spider would have to be kept
in a cage by itself, for when several are put together,
some of them will eat the others until only one is left.
This would make spider silk very expensive.

The webs are sometimes of quite intricate patterns.
When an insect flies into one of the webs, the watch-
ful spider hurries out and wraps it about with silk,
thus completely entangling it, and then proceeds to
eat the soft parts of the captive.

Some small spiders are enabled to travel long dis-
tances upon the webs they weave, which are buoyed
up and drifted about by the air.

The jumping spiders make no webs, but seize
their prey by jumping upon it. They are very
active. Among nearly all spiders, the female is the
larger.

The eggs of spiders are laid in a mass which, in
some species, is surrounded by a covering of silk and
either carried around by the spider or fastened to a
tree or other support. The metamorphosis is direct.

THE CENTIPEDE
(Scolopocryptops. )

1. Are there any body divisions? Identify the

head distinctly.
2. Are there any eyes? What kind?

64 INTRODUCTION TO ZOOLOGY.

3. How many antenne? How many segments in
each?

4. Find the mandibles. Are the things you take
to be mandibles, true mandibles? Are they on the
head? Are they jointed?

5. You may cail this pair of mandible-like appen-
dages the maxillipeds, or foot jaws.

6. Find and identify the true mouth parts. Draw
one of each pair.

7. How many body segments behind the head?
What does each segment bear? How do the legs
on the first segment differ from those on the other
segments? How do the legs on the last segment dif-
fer from the other legs?

8. Do you find spiracles? On what segments?
How many?

9. Do you see any way to explain why an insect’s
jaws move sideways?

THE THOUSAND LEGS.
(Polydesmus. )

1. Are there any body divisions? Identify the
head clearly.

2. Find and draw one of each pair of mouth parts
and antenne.

3. Find the eyes. Are they simple or compound?
How arranged? Compare with the eyes of a cater-
pillar.

4. How many segments in the body? How many
pairs of legs? Hold this fact until we study the
earthworm.

5. How many segments on each leg? Are all the
legs alike? Draw one.

6. Do you find spiracles? How many?

7. In what respects does a caterpillar resemble a
thousand legs?

ADDITIONAL FACTS ABOUT THE MYRIAPODS.

65

Make a table of differences between a butterfly and
a caterpillar, and in a parallel column compare the
thousand legs, in this manner :—

Butterfly. Caterpillar. Thousand Legs.
Body divisions..| 8.............. Db sesitei ada soles lead nae ees ates
By OS oeisieee ce compound ....) groupof simple|................
Wings s eesti |i Bak ee) sce TONG: iid. sitiiaconitie ss a ahieeele See ak oe
Mouth parts....| sucking. . ...| biting.........)............00e-
Food. ......... liquid......... BOLIC cits cetautsianea le ag baisedeesa¥e. tetuaety ties
Locomotion ....| fly ............ CRAWL sconces vesctos lira seergiaiianecee a area ere
Body Coverings.| scales........ hair or naked...|................
{ long and oes and in-
Antenne....... 1 knobbed ... conspicuous].........-...464%

From the similarities manifested by the foregoing
table, you will probably conclude that a caterpillar re-
sembles a thousand legs more closely than it does a but-
terfly.

Additional Facts About the Myriapods.

The centipede and thousand legs are taken to rep-
resent the class Myriapoda. The centipedes belong
to the order Chilopoda; and the thousand legs belong
to the order Chilognatha.

Make a table of differences between the two.

The centipede from which the outline is made, Scol-
opocryptops sexspinosus, is a small animal and is found
throughout the eastern and southern parts of the
United States. It is found usually under stones and
logs which lie on the ground. Its food is principally
earthworms, which it pursues into their burrows. It
is very active, and the strong maxillipeds enable it to
obtain a very firm hold on the body of the earthworm.
The hind pair of legs is directed backward, thus fur-
nishing it an anchor which will prevent its being
dragged along by the muscular efforts of the earthworm.
Living entirely in dark places, it has no need for eyes,
and the name Scolopocryptops indicates their absence.

66 INTRODUCTION TO ZOOLOGY.

The centipede is a very active and a very vicious
little creature. The usual way of catching one is to
seize it quickly with the fingers as soon as the stone is
turned over. In such a case, the centipede tries to
bite, and frequently succeeds. No poisonous effects,
however, have ever been experienced by the writer,
who must have been bitten a hundred times. The
large centipede of the southwestern states, Scolopendra,
is two or three times as long as the Scolopocryptops, but
resembles it closely in every structural respect.

The maxillipeds are remarkable organs. They are
located on a segment behind the head. They are
jointed. In both position and structure, they agree
with the legs. They must be homologous tolegs. But
they work sideways, like jaws, and are used as jaws.
The jaws (mandibles) have the same position they do.
So we must conclude that maxillipeds are homologous
to jaws. But by the axiomatic proposition that things
which are homologous to the same thing are homolo-
gous to each other, the mandibles of a centipede
must be homologous to the legs of a centipede. But
the mandibles of a centipede are clearly homologous
to the mandibles of a grasshopper. Therefore it seems
clear that the mandibles of a grasshopper are homolo-
gous to the legs of a grasshopper. We may illustrate
the homologies by a diagram :—

GRASSHOPPER. CENTIPEDE.
jaws = = jaws
ll
I }
fn Y
maxillipeds
I Il
i
legs <5 — legs

Therefore, ctc.

ADDITIONAL FACTS ABOUT MYRIAPODS. 67

This enables us to understand more clearly what
is meant by homology, and to explain why we count
one body segment in the head for each pair of paired
appendages, and so determine that the body of the
grasshopper is composed of seventeen body segments.
This also enables us to explain why the mandibles of
the grasshopper move sideways. The appendages are
paired on each segment, and so are brought to oppose
each other, just as the two hands of a man together
seize upon an object to hold it or to lift it up.

To the Teacher.

The utility of the study of homology is to train the mind to
perceive logical identity. The homology of the maxillipeds and
the demonstration of the identity of the jaws of a grasshopper with
the legs is an important lesson, and should be carefully prepared
and worked out.

CHAPTER V.

THE CRAWFISH.

1. How many body divisions? The front one
is called the head thorax, or cephalothorax. Find
a cross groove separating what might be called the
head from the thorax. This is called the cervical
groove.

2. Find the pointed projection in front. This is
called the rostrum.

3. The entire covering of the cephalothorax is
called the carapace.

4. How many segments in the abdomen? The
middle piece of the tail fin is the telson. Is there any
reason for calling it a segment?

5. To which segment are the side pieces of the
tail fin attached?

6. Separate the third segment of the abdomen
from the second and fourth. Remove the interior
contents. Examine. The dorsal part of the ring is
the tergite. (Compare with the name tergum of the
grasshopper.) The ventral part of the ring is the
sternite. The side pieces are the pleurites.

7. The appendages are the swimmerets. Observe
that each swimmeret is composed of a main stalk and
two branches.

8. The main stalk is the protopodite. The outer
branch is the exopodite. The inner branch is the
endopodite.

9. Do the side pieces of the tail fin have this
structure? Are they swimmerets?

68

THE CRAWFISH. 69

10. If the swimmerets on the first and second seg-
ments of your specimen are large, it is a male; if
they are small it is a female.

The Cephalothorax.

1. Lift up the free edge of the carapace. This
part of the carapace is the gill cover, or branchioste-
gite. Inside are the gills.

2. How many pairs of legs?

3. Examine one of the hind pair of legs. Of how
many segments is it composed? Draw.

4. Examine the third pair of legs. Draw.

5. Examine the first pair of legs. Draw.

6. Find the third, second, and first pairs of maxil-
lipeds. Draw one of each pair. Can you find a main
stalk and two branches?

7. Find the second and first pairs of maxille.
Draw one of each.

8. Find the mandibles. Find the mandibular
palpus. How many segments has it? If you pull off
the mandibles, you will probably find the large mus-
cles which move them.

9. Find the gills. Draw one. How many gills?
What appendages bear gills, and how many gills be-
long to each of these gill-bearing appendages?

10. In the front of the gill chamber, find the gill
scoop, or scaphognathite. To what appendage is it
attached? What is its use? What separates the gills
from the gill scoop?

11. Find the antennze. Can you discover a main
stalk and two branches? The two branches are very
unlike each other. Draw.

12. Find the antennules, or little antenne. Can
you find the main stalk and two branches? The two
branches are very similar.

13. Find the ears, or otocysts, on the upper side of
the basal joint of the antennules.

70 INTRODUCTION TO ZOOLOGY.

14. Find the eyes. Are they simple or compound?
See how they can move. Are they on stalks, or
are they sessile?

15. How many pairs of paired appendages has a
crawfish? If each pair of appendages indicates a seg-
ment, how many segments in the body of a crawfish? Is
any segment of the body withouta pair of appendages?

16. Put a piece of the shell into strong vinegar or
other acid. If bubbles arise, it indicates that the
shell is composed in part of lime.

The Internal Structure.

1. Carefully remove the carapace and pin the
crawfish, back upward, under water.

2. Find the heart. Note its shape and position.
Draw.

3. Find one artery leading backward, and three
leading forward. To what organs do the forward
arteries go?

4. Find holes, like slits, in the heart. How many?

5. Find the stomach. Trace the passage from the
mouth to the stomach. Is it behind or in front of the
heart? Is it in the head or in the thorax?

6. Slit open the stomach. Examine the inside.
Find three teeth, which constitute the principal part
of the grinding apparatus. Draw.

7. Trace the intestine to its outlet.

8. Distinguish other organs: liver, green gland,
and reproductive organs.

9. See the muscles in the abdomen which bend
and straighten it. Which muscle bends it, and which
muscle straightens it? The bending muscle is the
flexor, and the straightening muscle is the extensor.
Which muscle is the larger? ;

10. Separate the two parts of the flexor muscle
and find the nerve cord in the floor of the abdomen.

THE SOW BUG. 71

Isitdouble? How many ganglia do you count? Draw
a portion of the cord with its ganglia and nerves.

11. Trace the nerve cord through the thorax.
Find where it passes around the esophagus. Find
a ganglion above and below.

The Live Crawfish.

1. How does a crawfish move when swimming?
With what organ does he swim? How does he walk?

2. How does a crawfish breathe? Where does the
water go into the gill chamber? Where does it come
out? What makes the water flow over the gills? Puta
small drop of ink in the water near the hinder edge of
the carapace. Look for it to appear near the mouth.

3. Does a crawfish cast off its shell? Where does
a crawfish live? Is there more than one kind of
crawfish in our vicinity?

4. Why can a crawfish live out of water longer
than a fish?

5. Where are the eggs borne? Do the young
crawfishes look like the old ones?

THE SOW BUG.

1. Locate the head, thorax, and abdomen. How
many segments in the thorax? In the abdomen?

2. On the head, find theeyes. Are they stalked or
sessile? Simple or compound?

3. Find the antenne. How many segments? How
many pairs of antenna?

4. How many pairs of jaws? Draw one of each
pair. Are there palpi?

5. Find the legs. How many pairs? Do all the
pairs extend in the same direction? How many seg-
ments in each leg? Draw.

6. Find the gills, under the abdomen. How many?

7. Test the shell with acid. Is there any lime in it?

~I
Ww

INTRODUCTION TO ZOOLOGY.

THE CYCLOPS.

1. See the carapace.
How many segments
has the thorax?

2. Seetheeye. Isit
compound? Is it moy-
able?

3. How many joints
in the antennee?

4. How many seg-
mentsin theabdomen?
How does itend? How

any spines at the
tip?

CE CLOES: 5. If your specimen
is a female, note the external ovisacs. Trace the in-
testine.

THE DAPHNIA.

1. See the shell. Is it Rage mee
plain or reticulate?

2. Seetheeye. [sitsimple
or compound? Movable or
not? Notice the eye muscles.

3. Trace the intestine.
See the broad cavity above
the intestine. If your speci-
men is a female, you will
probably find eggs in it.

4. Find the heart. BAe &

5. Is there a spine at the SRR
posterior end of the abdomen?

6. Draw the antenne carefully.

Noter.—Daphnia and cyclops are too small to be satisfactorily
studied without a compound microscope. The student, however,
ought to become familiar with the general appearance of each as
seen by the unaided eye and with the simple lens.

ADDITIONAL FACTS ABOUT THE CRUSTACEANS. 73

A Additional Facts about the Crustaceans.

The crawfish introduces us to a different mode of
breathing ; that is, by means of gills. Breathing, or
respiration, consists essentially of an exchange of
gases. The tissues of the body need to be furnished
with oxygen. This oxygen must come indirectly
from the air. When oxygen reaches the tissues of
the body, some of it is used in doing work or in gener-
ating heat. The result in either case is the produc-
tion of carbon dioxide, which must be removed from
the body. In the crawfish, the blood carries the
carbon dioxide from the tissues, where it is generated,
to the gills. The water which flows over the gills
contains oxygen, which it has absorbed from the air.
The blood carrying carbon dioxide flows into the gill
filaments, where it is separated from the oxygen con-
tained in the water by only a thin, moist membrane,
which is the outer layer of the gill filament. Under
these conditions, the carbon-dioxide carried by the
blood leaves the blood and passes through the gill
membrane into the water, and the oxygen in the
water leaves the water and passes through the gill
membrane into the blood.

In order that this exchange of gases may take
place, the gill membrane must be kept moist. A
crawfish can live out of water as long as its gills are
moist. This will enable us to see the advantage of
the gill covering. It prevents the rapid drying out
of the gill and enables the crawfish to live some time
out of water. If necessary, the crawfish can travel
overland from pond to pond.

There must be oxygen in the water. Water that
has been boiled has had all the absorbed oxygen
driven off. So crawfishes cannot live in boiled water
unless it has absorbed oxygen since the boiling.
Water that has given up its oxygen to the gills must

74 INTRODUCTION TO ZOOLOGY.

be removed, and fresh water must take its place.
There is a necessity for the production of a current of
water over the gills. This is brought about by the
action of the gill scoop, situated in front of the gills.
The gill scoop, when working rapidly, moves about
three times in a second, and produces a current from
backward to forward.

Since this is the direction of the current of water
over the gills, it is an advantage in breathing for the
crawfish to swim backward. The movement back-
ward assists the current flowing over the gills. So,
also, when crawfishes lie in a running stream, they
will usually lie with their heads down stream.

The blood in crawfiishes is white, and it exists in
considerable quantity. When a legof a live crawfish
is cut off, the blood flows freely from the wound. It
contains an abundance of white corpuscles, but no red
ones such as we shall find in vertebrates.

Some kinds of crawfishes dig holes from the sur-
face of the land downward several feet, usually piling
the excavated dirt around the mouth of the burrow,
forming a chimney. These holes generally reach
downward to the water, and are most numerous in
low places, from the surface of which the water has
almost or quite disappeared.

Crawfishes molt as insects do. They molt about
five or six times the first year of their lives, and
usually molt once each year thereafter. A crawfish
may live to be twelve years old.

All crawfishes living in the eastern and central
part of the United States belong to the genus Cam-
barus, and have seventeen gills on each side of their
body. English crawfishes, and those of California,
have eighteen gills on each side and belong to the
genus Astacus.

The crawfish is the fresh-water lobster. In gencral
appearance, and in everything except size, the crawfish

REVIEW QUESTIONS. 75

and lobster are very nearly alike. A crab differs from
a crawfish in the fact that the abdomen is very much
reduced in size and is folded under the cephalothorax.

The sow bug belongs to an order called Tetrade-
capoda, or fourteen-footed crustaceans. The gills are
leaf-like plates situated under the abdomen. The
animal lives in damp places, although most members
.of the order are truly water animals.

Daphnia, Cyclops, and Cypris belong to the order
Entromostraca. They are all very small crustaceans,
are found abundantly in our lakes and ponds, and
furnish a part of the food for young fishes. The order
is now divided into three groups, called Copepoda,
Cladocera, and Ostracoda, represented by Cyclops,
Daphnia, and Cypris, respectively.

Review Questions.

THe CRAWFISH.

What are the body divisions of the crawfish?

What is the cervical groove?

Where is the rostrum?

Where is the telson?

How many segments in the abdomen?

What is the carapace?

Name all the appendages of the crawfish?

Are the eyes stalked or sessile?

What appendages bear gills?

How many gills does each of the gill-bearing ap-

pendages have?

11. What is the gill scoop? What is its use?

12. To what is the gill scoop attached?

13. Describe the function of the gills.

14. How is a current of water produced over the gills?
What makes it flow? Describe its course.

15. What is the typical form of an appendage? Name

the three principal parts.

=v
SO AID OB 29 PO

INTRODUCTION TO ZOOLOGY.

. Describe the two pairs of antenne.

. Where are the ears?

. How distinguish the male from the female?

. How many body segments? What indicates the

number?

. Which body segment bears no appendage?

. What pairs of legs are furnished with pincers?

. Where is the stomach?

. Describe the nerve cord. How many ganglia?

. Where is the heart? How does the blood get into

the heart?

. What kind of blood has the crawfish?

. What muscles enable the crawfish to swim?

. Why does the crawfish swim backwards?

. How is a crawfish enabled to stay so long out of

water?

. Where are the eggs carried?
. Of what is the shell composed?
. What is meant by the molting of a crawfish?

TuE SPIDER.

. How many body divisions has the spider?
. How is the web produced?

. What is silk? Where are the spinnerets?
. How many legs has the spider?

What are the breathing organs?

. How many eyes has the spider? Are they simple

or compound?

Tue CENTIPEDE.

. How many body segments has the centipede?

. Where are the maxillipeds borne?

. Where does the centipede live? What is its food?
. Is there any difference between the thorax and

the abdomen?

. How does a centipede differ from a caterpillar?

CLASSES OF ARTHROPODA.

77

Make a table of differences between the grasshop-
per, spider, centipede, and crawfish, after the follow-

ing plan :—

Grasshopper.
Insecta.

Spider.
Arachnida.

Centipede.
Myriapoda.

|

Crawfish.
Crustacea.

Body divisions .
Exoskeleton .....
Antenne
Eyes
Body segments .
‘Breathing ......
Number of legs.
Wings. ........
Locomotion ....

Habitat

Make a table of resemblances among the grass-
hopper, spider, centipede, and crawfish, according to
the following plan :—

all have exoskeletons
jointed appendages

meen white blood
ie tipede reproduce by eggs
Crawfish jaws move sideways

composed ,of body segments
double nerve cord and ganglia

Compare this table with the table on page 55.
Have any new resemblances been discovered? Have
any resemblances on page 55 been omitted? Look
for omitted resemblances in your table of differ-
ences.

The grasshopper, spider, centipede, and crawfish
represent four classes of animals that resemble each
other in the particulars indicated in the table. They
are grouped together, and the group is called a Branch.
The name of the branch to which these animals be-
long is Arthropoda. It is named from the jointed
appendages.

78 INTRODUCTION TO ZOOLOGY.

Logical Definition.

An insect is an arthropod which is composed of sev-
enteen body segments grouped into three body divisions ;
has a chitinous exoskeleton, one pair of antennee, and two
sessile compound eyes; breathes by spiracles which open
into trachexr ; has three pairs of legs and two pairs of
wings ; can move by flying ; and lives in the air.

From your table of differences, make a logical
definition of an arachnid, a myriapod, and a crusta-
cean.

CHAPTER VI.

THE FISH.

Almost any kind of fish will do for this study.
These directions are written for the perch or the sun-
fish.

1. Measure the length, from the tip of the snout
to the base of the tail. Measure the depth, the great-
est distance between dorsal and ventral sides ; width,
the greatest thickness from right to left; length of
the head, from the tip of the snout to the tip of the
bony part of the flap on the side of the body. How
many times is the depth, the width, and the length of
the head, contained ih the length of the fish?

2. Find the caudal fin, at the tail; the dorsal, on
the back; anal fin, the single fin below. These are
the unpaired or median fins.

3. The pectoral fins are the front pair of paired
fins. The ventral fins are the hind pair of paired
fins.

4. Study each fin. Find two kinds of fin rays,
and a membrane covering therays. Is the membrane
double or single?

4. The stiff, pointed rays are the spinous rays.
The others are the soft rays or jointed rays. How
many rays of each kind has each fin? D. III., 10,
means that the dorsal fin (D) has three (III.) spinous
rays, and ten (10) soft rays. So indicate the number
and kind of rays in each fin.

6. Study the rays. Dothey branch? Draw care-
fully one of the soft rays. Sketch each fin.

79

80 INTRODUCTION TO ZOOLOGY.

The Eyes.

1. Are the eyes movable? Are there eyelids? In
what direction can this fish see? What parts of the
eye can you see?

2. Find the anteorbital bone in front of the eye,
and the suborbital below it.

3. Insert your finger into the mouth and find out
whether there is a bone between the mouth and the
eyeball.

The Nostrils.

How many nostrils (nares) are there, and how are
they situated? Do they open into the mouth? Of
what use are they?

The Mouth.

1. See how the jaws open. Note the shape of the
mouth, when it is open and when it is closed.

2. The bones in the upper lip are the premaxil-
laries. How many?

3. Observe the backward extension of the premax-
illary on top of the snout.

4. Do the premaxillaries bear teeth?

5. Observe the bones just back of the premaxil-
laries. These are the maxillaries. Do they have
teeth? What is their shape?

6. Find a small patch of teeth in the roof of the
mouth. These are borne on a bone called the vomer.

7. Find two bones (palatine bones) along the sides
and a little way back of the vomer. Do they have
teeth? “

8. The front bone of the lower jaw is the dentary.
Does it have teeth?

9. Examine the tongue. Can it be thrust out of
the mouth? Does it bear teeth?

10. Can you find teeth anywhere else in the mouth?

THE FISH. 81

The Gill Covers.

1. The gill covers are composed of four bones, the
opercular bones. : .

2. The upper back one is the opercle. The upper
front one is the preopercle. The lower back one is
the subopercle. The other bone is the interopercle.

3. Look below the opercular bones for the bran-
chiostegal membrane, which is supported by the bran-
chiostegal rays. How many rays are there? Draw
the external appearance of the gill covers ;

4. See the narrow part of the body between the
branchiostegal rays. This is the isthmus.

The Gills.

1. Raise one gill cover and find the gills. Find
the bone which supports a gill. This is the gill
arch. The small threads attached to it are the gill
filaments.

2. The spaces between the gill arches are the gill
clefts. How many gill arches? How many gill clefts?
How many rows of gill filaments on each gill arch?

3. Find the gill rakers on the front side of the gill
arches. Are all the arches supplied with them? On
which*gill are they the longest?

A. Find a red line, the gill artery, along the base
of the gill filament.

5. Find a red spot, like a gill, on the inside sur-
face of the operculum. It is a false gill, or pseudo-
branchia.

The Scales.

1. How are the scales arranged? Is there a cover-
ing (epidermis) over the scales? Pull a scale out of
a yellow or black spot. In what is the color?

2. Examine one of the scales after it has been pulled
out. Notice radiating strize running from the edge.

82 INTRODUCTION TO ZOOLOGY.

3. Notice concentric strie running around the
edge.

4, Which is the anterior and which the posterior
edge of the scale?

5. Note fine teeth on the posterior edge of the
scale. Draw.

6. Find a distinct line running along the sides of
the body lengthwise. This is the lateral line.

7. Pull one scale out of the lateral line. Ex-
amine carefully. How does it differ from other
scales?

8. How many scales in the lateral line?

The Body Cavities.

1. Find the opening of the intestine, in front of
the anal fin. Cut through the body wall carefully
from the anal opening to the isthmus. Cut away as
much of the body wall on the left side as you can
without injuring the internal organs.

2. Notice the silvery lining of the body cavity.
This is the peritoneum.

3. Find a membranous partition near the front of
the body cavity. This is the false diaphragm. The
part of the body cavity in the front of it is the peri-
cardial cavity. The part behind it is the abdominal
cavity.

4. In the dorsal part of the abdominal cavity, find
a thin membrane. ‘This isthe air bladder. Does the
peritoneum cover it? Does it have any connection
with the mouth or stomach?

The Digestive Organs.

1. Identify as well as you can the esophagus,
stomach, intestine, liver, spleen.
2. What is the shape of the stomach? Where does

THE FISH. 83

the cesophagus enter it? Where does the intestine
leave it?

3. Find the pyloric ceca, at the place where the
intestine leaves the stomach. How many? Scrape
away the fat and examine one carefully.

4. Trace the intestine. How many turns does it
make? Notice the thin membrane (mesentery) which
holds the loops of the intestine together. Where is it
attached? Do you find any tubes running in it?

5. How many lobes has the liver? Where is it
attached?

6. Find the bile sac, on one of the lobes. Is there
a connection between the bile sac and the intestine?
Draw. What is the use of the bile sac?

7. Identify the spleen. This is a small, red body
back along the intestine.

The Reproductive and Excretory Organs.

1. Identify the reproductive organs, male or
female. Ifa female, the ovaries will show the eggs.

2. Is there a tube leading from the reproductive
organs? Where does it open?

3. Find the kidneys. They are dark, slender
bodies along the roof of the abdominal cavity.

4. Trace the kidneys backward to the urinary
bladder. Where is the outlet?

The Circulation.

1. Identify the heart. The larger, angular por-
tion is the ventricle. The softer, irregular portion is
the auricle.

2. Find the venous sinus, a dark, thin-walled sac
extending back from the auricle and in front of the
false diaphragm. Can you find its opening into the
auricle?

3. Find the hepatic vein, passing from the liver

84 INTRODUCTION TO ZOOLOGY.

through the false diaphragm into the venous sinus.
Are there other veins entering?

4. Find the arterial bulb in front of the ventricle.
Trace the branchial aorta from the arterial bulb until
it branches into the branchial arteries, one to each gill
arch.

5. Trace one branchial artery along the gill arch
until it enters the dorsal aorta.

6. Trace the dorsal aorta along the back as far as
you can.

7. Is the heart single or double? Is it respiratory
or systemic? Describe the course of the blood from
the ventricle until it gets back to the ventricle again.

The Nervous System.

1. Cut off the head, scrape away the flesh, and
slice off the top of the skull to see the brain.

2. Notice the cellular tissue above the brain.

3. The largest pair of lobes you see in the brain
are the optic lobes.

4. In front of the optic lobes, find the pair of cer-
ebral hemispheres, or cerebrum.

5. In front of the cerebrum, find two much smaller
lobes, the olfactory lobes. Trace the olfactory nerves
from the olfactory lobes forward.

6. Behind the optic lobes, notice the undivided
cerebellum.

7. Behind the cerebellum, find the medulla ob-
longata, which is continuous with the spinal cord.

8. Find the optic nerves, below the cerebral and
olfactory lobes. Trace them to the eyes. Do they
unite? From which lobe does the nerve come that
goes to the right eye?

9. Can you find small nerves (spinal nerves)
branching from the spinal cord? How far back does
the spinal cord extend?

ADDITIONAL FACTS ABOUT THE FISH. 85

The Skeleton.

1. Clean the flesh from one of the bones of the
spinal column.

2. Note the central portion (centrum). What
shape is it on the ends?

3. Note the spinous processes. The one on the
back is the neural spine. See the opening through
which the spinal cord passed.

4, How many pairs of ribs has your fish? How
are the ribs attached to the backbone?

5. To what are the fin rays attached?

The Live Minnow.

1. How does the fish swim? What is the chief
organ of locomotion?

2. What is the chief use of each one of the fins?

3. Notice the action of the mouth and gill covers.
Do both mouth and gill covers move at the same time?
Why does the fish move his jaws so constantly?

4. Why does the fish generally lie with head up
stream? Why does a fish die when it is taken out of
the water?

5. Will these minnows ever grow larger? How
many kinds of fishes do you know? How many kinds
are on sale in the markets?

6. Do fishes ever rain down?

Additional Facts About the Fish.

The fishes represent the class Pisces. There are four
groups of this class. Each group may be called an
order, although each has been subdivided into several
orders since the first division was made. The bony fishes
belong to the order Teleostei. The sharks belong to
the order Selachii, the sturgeon and garpike belong to

86 INTRODUCTION TO ZOOLOGY.

the order Ganoidei, and the Australian, African, and
South American lung fishes belong to the order Dipnoi.
The Selachians have a skeleton that is cartilaginous
throughout, while the skeleton of the Ganoids and of
the Dipnoi is partly cartilaginous and partly bony.

The tail is the principal organ of locomotion. The
other fins serve mainly to balance the fish, keeping it
upright and guiding it in its course through the water.
The pectoral and ventral fins are homologous to the
fore and hind limbs of a dog or other mammal.
Usually the pectoral fins are in front of the ventral
fins, but this is not always so. When the ventrals
are anterior to the pectorals, their ventral nature can
be recognized by their being closer together and
nearer the median line of the fish than the pec-
torals.

The vertebrae are concave at both ends. The spaces
between the ends are filled with a cartilaginous sub-
stance which represents the notochord. The noto-
chord is a cartilaginous rod which is found in the
early life of every vertebrate, occupying the place of
the backbone. In the sturgeon, and in other fishes
with cartilaginous skeletons, the notochord persists
throughout life; but in the bony fishes generally, as
well as in all other vertebrates, bony vertebree take
the place of the notochord.

Usually, the tail fin is two-lobed and the lobes are of
equal size. The spinal column ends at the place in
which the tail fin begins. Such a tail is called
homocercal. But in the sharks, and in some other
fishes, the backbone seems to run out into one of the
lobes of the tail, making that lobe much larger than
the other. Such a tail is called heterocercal.

The fish breathes by gills, as the crawfish does.
The water, however, goes over the gills from the front,
instead of from behind. It enters the mouth when
the mouth is open, and the closing of the mouth forces

ADDITIONAL FACTS ABOUT THE FISH. 87

it out over the gills and under the gill covers. If a
fish were to have its mouth propped open, it could
not produce this current, and so would very likely
suffocate. Since the current of water is backward
over the gills, it is easier for the fish to breathe when
it is fronting up stream. If it were held with the
head down stream in a swiftly flowing current, it
would have great difficulty in breathing. So, in
running water, fishes generally lie with their heads
up stream, and they swim up stream in preference to
swimming down. In this way fishes are distributed
to small streams, and at the time of a heavy rain,
when furrows and ditches are filled with water, they
may reach ponds that on ordinary occasions have no
outlet, or may even be stranded on places that are dry
when the rain is over. This is a sufficient explana-
tion for most of the stories that we hear of fishes
raining down.

The blood is red. It consists of many red corpus-
cles and a smaller number of white corpuscles floating
in a liquid called the plasma. Each red corpuscle
has a small body in the center called the nucleus.
The blood of a fish has the same temperature as the
water in which it lives. As the water in which a fish
lives is generally colder than our bodies, and so feels
cold to our hands when we put them into it, we say
that the fish is cold blooded.

The heart consists of one auricle and one ventricle.
Such a heart is said to be single. The blood is sent
forward to the gills. In consequence of the fact
that all the blood is sent from the heart to the breath-
ing organs, the heart is said to be a respiratory heart.

When a fish is taken out of the water, it can live
only so long as the gills are kept moist. When the
gills dry out, as they do very soon, the membrane of
the gills cannot exchange the respiratory gases, and
the fish dies of suffocation. The gills of a fish are not

88 INTRODUCTION TO ZOOLOGY.

so well protected against drying out as are the gills of
a crawfish, so a fish cannot usually live so long out of
water as a crawfish can.

From the gills the blood is gathered into the dorsal
aorta, through which it is distributed to the body gen-
erally. It returns from the body through veins to the
auricle. Since no part of the blood, after leaving the
heart, can return to the place from which it started
without passing both through the breathing organs
and through some part of the system, the circulation
is said to be complete.

The air bladder is homologous to a lung, although
in our common fishes it is not a breathing organ. It
is filled with gases secreted from the blood, and serves
to make the body of the fish have the same specific
gravity as the water in which it lives. If the muscles
along the sides of the body contract, the air bladder
is compressed, thus occupying less space, which action
increases the specific gravity of the fish, enabling it to
sink more readily. In the perch, the air bladder is
attached to the walls of the body cavity. In the suck-
ers, and in many other fishes, it lies free in the body
cavity and is divided into two portions by a constric-
tion around the middle. In the garpike, and in the
ganoids generally, the air bladder contains many blood
vessels and communicates with the esophagus by a
short tube through which air can enter it. In these
fishes, it serves as a partial lung and is of use in
breathing. In the Dipnoi, or lung fishes, it is so
efficient that, when necessary, the use of gills can be
dispensed with, and the fishes are thus enabled to
withstand for some time a complete drying up of the
ponds in which they live.

In the perch, and in most bony fishes, the air blad-
der represents an organ that is in a state of retro-
gression. Instead of becoming more lung-like, it is
becoming less so.

REVIEW TOPICS ON THE FISH. 89

The scales on the fish represent the exoskeleton.
The bony skeleton inside, to which we refer when we
speak of the skeleton, is the endoskeleton. The scales
are entirely distinct from this. The scales along the
lateral line are perforated, allowing communication
with a series of lateral line sense organs, whose nature
is not satisfactorily known. Perhaps their function is
somewhat similar to that of the ear.

In the skin are located many muciparous glands
which furnish a secretion that lubricates the fish in
its passage through the water. This is what makes a
freshly caught fish feel so slippery.

In the catfish, and in many other kinds, the skin is
naked and the exoskeleton is undeveloped. In the
sturgeon, the exoskeleton is developed as a series of
bony plates.

Review Topics on the Fish.

Name all the fins of a fish.

Describe the structure of a fin.

What are the two kinds of fin rays?

How are the scales arranged?

What is the lateral line?

How many scales in the lateral line?

What is the principal organ of locomotion?

Name the opercular bones.

Describe the structure of a gill.

State the direction of the water as it goes over
the gills.

11. What makes the water flow over the gills?

12. What does the fish breathe?

13. Why does a fish lie with its head up stream?

14. Describe the course of the blood through the

body, naming all parts of the heart.

15. Is the circulation double or single?

16. Is the circulation complete or incomplete?

17. What is the false diaphragm?

rary
SWHMOAIRBAP WHE

i

. What are the pyloric ceca?
What kind of blood has the fish?

. Why is a fish said to be cold blooded?

. Sketch the brain, naming all the parts in their order.
. Sketch a vertebra, naming all the parts.

INTRODUCTION TO ZOOLOGY

Vocabulary of a Fish.

Words to be pronounced, spelled, and defined with
reference to the specimen studied.

ddér’sal

vén'tral

snout

spi’nous
cau'dal

ho mo g@r’eal
het er o ¢ér'eal
inal

pée'to ral

pre mitx’il la ry
dén'ta ry
vo'mer

pil’a tine

o pér'ele

bran ehi 6s'te gal
gill

stri'e

ep i dér’mis

lat’er al line

per i to né’um

he pitt'‘le vein

gtil'let

ge'eal stom’ach

pneu mo gis’trie
nerve

py lor'ie ge’ea

més’en ter y

spleen

o'va ry

a'vi duet

kid’neys

di’a phragm

vén'tri ele

au'ri ele

vée'nous si’nus

ar té’ri al bulb

a or'ta

phar yn ge’al teeth
ver'te bree

gén'trum

net'ral spine

me dil’la ob lon gi’ta
ger e bél’lum

Sp'tie lobes

gér’e brum

ol fie'to ry lobes
periecir'dial eiv'i ty
fil'a ment

CHAPTER VII.

THE FROG.

1. Find the eyes, nostrils, mouth. Has the frog a
neck? How many eyelids?

2. Find the ears. Notice the white spot in the
center.

3. Has the frog teeth? If so, where? Examine
the tongue. Where attached? Is it forked or not?
Of what use is the tongue?

4. Study the legs. How do the fore and hind legs
differ? How many toes on each?

5. The parts of the fore leg are arm, forearm, and
hand.

6. The parts of the hind leg are thigh, leg, and foot.

7. Notice the color and texture of the skin.

Internal Structure.

1. Remove the skin from the ventral side and cut
through the body wall. Is there any diaphragm?

2. Identify the liver, stomach, intestine, heart, and
lungs.

3. Beginning at the stomach, trace the intestine
its entire length.

4. Notice the mesentery, which holds the intestine
in place. In the mesentery, near the stomach, find
the pancreas.

5. How many lobes has the liver? Find the
bile sac.

6. In the mesentery, posteriorly, find the spleen.

91

92 INTRODUCTION TO ZOOLOGY.

7. If your specimen is a female, find the ovary
with its much contorted oviduct leading to the cloaca.

8. In many specimens you will find slender masses
of fat. These are the fat bodies.

9. Find the kidneys, which are elongated dark
bodies near the hind part of the backbone. From the.
kidneys, trace tubes, the ureters, backward to the
urinary bladder.

10. Notice the lungs. Trace the trachea from the
larynx to the lungs, observing the bronchial tubes.

11. Notice the great size of the lung cells, and the
small number of them which constitute a lung.

12. Find the heart. Find where the aorta divides
into two branches, the right and the left aorta. Find
the three principal branches into which each aorta
divides: the carotid, leading to the head; the pulmo-
cutaneous, leading one part to the lungs and the other
to the skin ; and the aorta proper, which leads to the
rest of the body generally.

13. Trace the right and left aorta until they come
together, forming the dorsal aorta. Continue until
you find the iliac arteries, which lead to the hind legs.

14. Find the veins which bring the blood back to
the heart.

15. How many cavities are there in the heart?

16. Make a diagram of the frog’s circulation.

The Nervous System.

1. Find all the nerves you can that run from the
spinal cord to the body cavity.

2. Notice the brachial plexus, sending nerves to
the fore legs.

3. Notice the plexus of nerves going to the hind legs.
Trace the principal nerve (sciatic) as far as you can.

4. Cut away the top of the skull, exposing the
brain. Identify the following parts: optic lobes,

THE FROG. 93

which form the widest part of the brain; cerebrum,
consisting of two elongated lobes in front of the optic
lobes; olfactory lobes, very small, in front of the
cerebrum ; olfactory nerves, running under the ol-
factory lobes to the nostrils; cerebellum, very small,
lying behind the optic lobes; medulla oblongata, con-
tinuing into the spinal cord.
5. Trace the optic nerves to the eyes.

The Skeleton.

1. Has the frog ribs? How many yvertebre has it?

2. Notice the three long bones at the back of the
spinal column. The middle one is called the urostyle.
The bone on each side of it is called the ilium. What
makes the frog look humpbacked?

3. Identify the bones of the fore leg and the
shoulder girdle. The bone in front, on the ventral
side, is the sternum. Of how many pieces is it
composed?

4. The dorsal part of the girdle is composed of the
scapule. The cartilaginous portion is called the
supra-scapula. Note the two coracoid bones, and
the two clavicles in front of them, all extending from
the sternum to the scapula.

5. The first bone in the arm is the humerus. The
next is the bone of the fore-arm, the radius. The bones
of the hand are the carpals, metacarpals, and phalanges.

6. Study the bones of the hind leg. Identify the
femur, the tibia, the tarsal bones, the metatarsals,
and phalanges.

7. Examine the skull. Is the lower jaw attached
directly to the skull?

8. Observe the movement of the skull in nodding.
A rounded prominence on the skull, fitting into a con-
cavity of the first vertebra, is called a condyle. Do
you find one or two condyles?

94 INTRODUCTION TO ZOOLOGY,

Additional Facts About the Frog.

The frog breathes by lungs, but the lung capacity
is small in consequence of the small number and large
size of the air cells. Blood is plentifully supplied to
the skin by a branch of the pulmo-cutaneous artery.
The skin is naked, and when moist, an exchange of
carbon dioxide for oxygen can take place through it
quite readily. This supplements the lung breathing.
This accounts in part for the fact that frogs are usually
found near a pond or stream of water. When the
ground or grass is wet, however, frogs often go long
distances from a pond. A frog confined in a dry place,
without water, will soon die.

Small frogs and toads are sometimes seen hopping
over the ground in great numbers, usually after a
rain, and this has led to a belief that frogs and toads
rain down. The true explanation is that a great num-
ber of tadpoles have been developed in a near-by pond
or some other body of water, and are just ready to
move out from the pond. They seize upon the time
of a rain, when the ground and grass and atmosphere
are very moist, to leave the place of their develop-
ment for some place where food can be more easily
secured.

The heart has three chambers: two auricles and
one ventricle. Only impure, or carbonated blood, is
poured into the right auricle, and oxygenated blood,
which comes from the lungs, into the left auricle.
The two kinds mix in the ventricle, but by a curious
arrangement of valves in the beginning of the aorta,
the greater portion of the blood that goes to the lungs
is that which comes from the right auricle, and the
greater part that goes to the system is that which
comes from the left auricle. This kind of circulation,
in which pure and impure blood mix in the heart, is
called a double, incomplete circulation.

THE FROG. 95

The two branches into which the aorta separates
come together behind the heart, forming one dorsal
aorta.

large and elliptical in outline, and
each is provided with a nucleus.
With a compound microscope the
movement of blood corpuscles can
be seen in the capillaries of the
web of a frog’s foot. It can also
be observed in the tail of a tad-
pole, in the tail fin of a minnow,
and in the mesentery of a living
frog or toad. Even with a simple
lens some movement may be ob-
served.

The corpuscles of the blood are ony [3 Se =|

BLOOD CORPUSCLES OF FROG.

The intestine opens into a short, wide sac called
the cloaca, which receives also the oviducts and the
tubes from the kidneys. The long bones of the legs
terminate in cartilaginous caps which are easily sep-
arated from the rest of the bones.

The frog is without any ribs or diaphragm. In
man, these are the organs by means of which the air
is taken into the lungs. The frog must breathe in
another way. Under the throat or jaw is a large,
flat muscle called the mylohyoid muscle. When
this muscle is depressed, the cavity of the mouth
is enlarged, and air rushes in through the nos-
trils. The nostrils are then closed, either by valves
in the openings, or by the tip of the tongue, or
by both, and the mylohyoid muscle is raised.
The air is thereby forced down into the lungs. The
process is repeated, air coming from the lungs and
mingling in the mouth with fresh air from the out-
side. If a frog’s mouth were propped open, could
he breathe?

os XN
96 INTRODUOTION TO ZOOLOGY.

THE TOAD.

Study a toad in the same way that you did a frog.
Make a table of differences, as follows :—

Frog. Toad
Sins cere. sy SMOOLBs ccs s Keer meriorsss WAEbY” vicewiessiere oars
Hind legs.......... SULONG 3% cea) a nme weak ....--.... go Vane
Habitat ............ near water ........... on land .isceee snes.
BPS sexcansa a uses in a glairy mass...... laid in strings... ....
Tadpoles. ......... lighter colored... ..... black, small .........

Additional Facts About the Toad.

The toad is very similar to the frog in general ap-
pearance, but its body is thicker, its legs shorter and
weaker. Its skin is warty and it is not confined to
proximity to water. The skin is furnished with
glands, from which a disagreeable liquid may be
ejected when the toad is excited by danger or fear of
danger. While the liquid is not poisonous, it is suffi-
ciently disagreeable to be fairly effective as a means
of defense. There is no foundation for the common
juvenile belief that handling toads will make warts
on a person’s skin. The toad generally remains con-
cealed under a stone or doorstep or other suitable
object in the daytime, and begins active operations in
the early evening. It catches earthworms, caterpil-
lars, beetles, and other insects. The tongue is quite
extensible, and is attached in front, the free tip
lying back in the mouth. This arrangement allows it
to be extended farther than it could be if it were
fastened at the back,as the human tongue is. It is
covered with a slimy, sticky secretion that causes an
insect to stick toit when brought into contact with it.
The toad catches insects by darting its sticky tongue
out upon them. Itis avery skillful marksman, and

THE TADPOLE. 97

seldom misses its aim. Collectors of insects often
examine the stomachs of toads, finding in them some
kinds of beetles the collectors themselves have over-
looked. Every toad is a valuable assistant to crop
growers, and it should not be killed, except when
needed for other purposes. Upon the approach of
winter, frogs and toads conceal themselves either in
the mud at the bottom of a pond, or in a hole in the
ground. Here they remain all winter, without eat-
ing, or breathing very much. On the approach of
spring, they come out of their winter quarters prepared
for another summer’sactivity. Stories of living toads
having been found embedded in rocks, where they
have lain for thousands of years, are probably all un-
true. None have been satisfactorily authenticated.

The Tadpole.

1. Notice the shape of the body. In what direction
(laterally, or vertically,) is the tail flattened?

2. See the mouth. Is it large or small? Has the
tadpole eyelids? Has it legs?

3. Notice the intestine. Cut through the body
wall and examine it. How long is it? Is it
longer, or shorter, than the intestine of a frog?
Remove it.

4. See the gills. How many? Draw.

5. Find the heart. Trace the artery to see whether
it goes to the gills or to the system. How many
chambers has the heart?

6. Examine a large tadpole. Which pair of legs
begins to grow first? What becomes of the tail?
What do tadpoles eat?

7. What is the difference between toad tadpoles
and frog tadpoles?

8. What is the difference between toad eggs and
frog eggs?

98 INTRODUCTION TO ZOOLOGY.

Make.a table of differences between a frog and a
tadpole. After this has been made, make another
column to the table for the statement of the character-
istics of a fish. In how many characteristics is the
tadpole unlike the frog and like the fish? What is
the strongest statement you can make about the
similarities of the tadpole and the fish?

{

Frog. Tadpole. Fish.

Shape.......... froP@ei ke: cainnieawisies| sceees eee yall ees Gethanele Rat
Breathing...... lungs
Mouth. .......
Appendages....
Padhiccss” a even
Heart..... 3
Circulation ....
Locomotion ...

Eyelids ..
Intestine .
Food..... ees
Habitat ........

Review Questions on the Frog.

1. How many eyes has a frog? How many eyelids?
With which does it wink?

2. Is there a third eyelid?

3. Are the eyes movable?

4. Has the frog a neck?

5. Where are the nostrils? Do they open into the
mouth?

6. Describe the ears. What is the white spot in the ear?

7. Has the frog teeth?

8. Where is the tongue attached?

9. Is the tongue forked or round?

10. Of what use is the tongue? How does the frog

seize its food?
. Is the skin covered?

po
ron

VON BAER’S PRINCIPLE. 99

. What is the difference between the fore and the

hind legs?

. How many toes on each foot?
. What are the parts of the fore leg? Of the hind

leg?

. Is there a diaphragm?

. Are there any ribs?

. How does a frog breathe?

. What organs in the body cavity?

. What shape is the stomach?

. How many lobes has the liver?

. Is there a bile sac?

. Is there a cloaca?

. What tube leads air into the lungs?

. Where is the larynx?

. What is the size of the Jung cells?

. How many chambers has the heart?

. Describe the aorta.

. What branches does the aorta give off?
. What veins bring blood back to the heart?
. How many vene cave?

. What veins unite to form each?

. Name all the parts of the brain.

. What nerves did you see?

. How many spinal nerves?

. How many roots has each nerve?

. How many vertebrae?

. Name the bones of the pelvic girdle.

. Name the bones of the shoulder girdle.
. How many condyles?

. Where is the mylohyoid muscle?

. What are the breathing organs of a tadpole?

Von Baer’s Principle.

When the frog eggs are first laid, each consists of

a single cell. Under proper conditions, the egg cell

100 INTRODUCTION TO ZOOLOGY.

divides into two cells nearly equal to each other in
size. These two cells divide again, thus forming four
cells nearly equal in size. This process continues,
each cell dividing into two, until the whole mass of
the ege consists of many cells.

At this stage, and for some time afterward, there
is nothing in the appearance of the egg itself that
would indicate whether the egg is to develop into a
vertebrate or into an invertebrate. Its vertebrate
characteristics do not begin to appear until after it has
manifested the characteristics of an invertebrate
animal. In fact, we may say that at one stage of its
existence, the tadpole, or frog, manifests all the char-
acteristics of an invertebrate. For our present pur-
pose, we may say that it passes through the same
stages that a worm does, for we may take a worm as
being a typical invertebrate.

Later, the vertebrate characteristics begin to ap-
pear, but it is not yet afrog. It begins to show red
blood, a two-chambered heart, and gills, and blood
goes from the heart to the gills just as it does ina
fish. In fact, it is a fish. Afterward the four legs
appear, while the tadpole still keeps its tail. If we
compare the tadpole in this stage with the salamander,
we see that the two are almost identical, both being
tailed Batrachians. But the tadpole goes on to an-
other stage. Its tail disappears and it becomes a
frog.

We may arrange the steps as follows :—

Table of Stages in the Development of a Frog.

Invertebrate. Fish.

Batrachian. Batrachian.

Single Tailed Tailless
Animal Cell.

| Dye ae worm ....| tadpole | salamander.. | LTO siete

VON BAER’S PRINCIPLE. 101

If we study the development of any animal, we
find a similar series of changes, except that the devel-
opment does not always stop with the batrachian.
The rabbit, for example, begins as a single animal
cell,anegg. It next shows the characteristics of an
invertebrate, a worm. Then it comes to have a two-
chambered heart and rudimentary gills, like a fish.
Next the heart becomes three-chambered and lungs
are developed, as in a frog oraturtle. There is so
much resemblance between reptiles and batrachians
that the two classes of animals are sometimes placed
in one group. The reptile is the best type of this
group, which would include batrachians, reptiles, and
birds. We may say, then, that the rabbit, at one time
in its history, is a reptile. But it does not stop here.
The heart becomes four-chambered, its body becomes
covered with hair, it acquires teeth, and comes to have
the characteristics of a mammal.

Let us put these facts into a table :—

Table of Stages in the Development of a Mammal.

Single Animal Cell. Invertebrate. | Vertebrate. | Reptile. Mammal.

fish; 3. | reptile. | mammal...

This is called the ONToGENETIC OR EMBRYOLOGIC
SERIEs.

If we take all the animals that now exist and
arrange them in the order of their complexity, placing
the simplest first, we shall have another series.

The simplest animals are one-celled animals. They
consist of a single animal cell, thus corresponding in
complexity to an egg.

The next degree of complexity is represented
by the invertebrates. This is a very large group

102 INTRODUCTION TO ZOOLOGY.

of many degrees of complexity. As we have yet
studied only one branch, we shall take the inverte-
brates as a whole and let them be represented by a
worm.

The simplest class of vertebrates is the fish. The
next group of vertebrates, representing a greater
degree of complexity, is the group which includes
batrachians, reptiles, and birds. We may take the
reptiles as representing this group.

The animals of greatest complexity are repre-
sented by the mammals, of which we take the rabbit
as a type.

Arranging these living animals in a series, we shall
have the following :—

Table of Animals Now Living.

1 2 : 3 4 5
Protozoa. | Invertebrates. Fishes. Reptiles. | Mammals.

Egg......-- WONT cine n caved iS reptile..... | mammal...

This is called the ZodLocic on TaxoNoMIc SERIES.

Next, if we take the animals that have existed and
arrange them in the order of their appearance upon
the earth, we shall find that the first animals which
appeared were undoubtedly protozoans. Each one
consisted of a single animal cell. Therefore, they
were comparable in complexity to an egg.

The next group of animals to appear were inverte-
brates. One great period of time is called the Age of
Invertebrates. We may let the worm represent the
animals which appeared at that time.

Another geologic period is called the Age of Fishes,
which succeeded immediately the Age of Invertebrates.

Then followed the Age of Reptiles, and finally the
Age of Mammals.

VON BAER’S PRINCIPLE. 103

Putting these facts into a table, we have another
series :—

Table of Animals Arranged in the Order of their
Appearance upon the Earth.

1 2 3
Protozoa. | Invertebrates. | Fishes.

A

4
Reptiles. | Mammals.

WOLD sis oiccticns ade fish... | reptile .... | mammal...

This is called the GEroLocic oR PHYLOGENETIC
SERIES.

Now putting these Taree Series together, we shall
have the following arrangement :—

Ontogenetic or Em-

bryologic Series ..Jegg .... ...... worm. | fish |reptile |mammal

Zodlogic or Taxo-
nomic Series. ....|protozoan; egg

worm | fish |reptile |mammal

Geologic or Phylo-
genetic Series. ..|protozoan; egg

worm | fish [reptile |mammal

We see that there is a complete correspondence in
the three series. This is what makes men believe
that the higher orders of animals in the history
of the earth have been developed from the lower,
and that each animal represents in its development
(Ontogeny) the history of the race from which
it is descended. This last statement is known as
von Barr’s PRINCIPLE.

CHAPTER VIII.

THE PIGEON.

1. Identify the head, beak, and upper and lower
mandibles. Can the upper mandible move without
moving the skull?

2. Find the nostrils. Insert the head of a pin
into the nostrils, to see where they open into the
mouth.

3. Observe the swollen membrane, beneath which
the nostrils open on the outside.

4. Find the tongue and notice its peculiarities.
At the base of the tongue, notice an opening into the
windpipe. It is the glottis.

5. See the eyes. How many eyelids do you
find? The transparent one is the nictitating mem-
brane. In what direction does it move? What is
its use? Is there anything homologous to it in your
own eye?

6. Find the ears. What peculiarity of the feathers
around the ear? Draw the head.

The Legs.

1. The segment of the leg next to the body is the
thigh. Its bone is the femur.

2. The bone of the leg, or drumstick, is the tibia.

3. The next part of the leg is the tarsus. Is it
feathered? Which joint corresponds to the knee?
Does a knee ever bend backward?

4. How many toes on each foot? How arranged?

104

THE PIGEON. 105

How many bones, exclusive of claw, in the hind toe?
In the inner toe? Middle? Outer?
5. What is the covering of the toes and the tarsus?

The Wings.

1. Find three parts of the wing; viz., the arm,
forearm, and hand.

2. The large feathers growing on the hand are pri-
maries. Those on the forearm are secondaries. If any
large feathers grow on the arm, they are called tertiaries.

3. How many primaries are there? How many
secondaries?

4. Observe that one side of the primaries is larger
than the other. Which side overlaps? Why?

5. Find smaller feathers covering the bases of the
primaries and secondaries. These are the wing cov-
erts, upper and lower.

6. Find the thumb, which bears one primary, the
spurious primary. Has it any coverts?

7. Count the tail feathers. Find the upper and
lower tail coverts.

8. The bunches of large feathers on the shoulders
are the scapulars.

The Body.

Pick the pigeon, preserving some of the feathers
for future study.

1. Do you find anything besides feathers on the
body?

2. Are the feathers arranged in rows, or are they
scattered promiscuously over the body? Are there
any places where there are no feathers? Can you
recognize any down? Any pin feathers? What are
pin feathers?

3. See the oil gland on the dorsal side of the tail.
What is its use?

106 INTRODUCTION TO ZOOLOGY.

The Internal Structure.

1. Insert a tube into the mouth and inflate the
crop. Carefully remove the skin and inflate again.

2. Loosen the crop from the neck and breast.

3. Find the windpipe, or trachea. Describe its
structure. bs

4. On each side of the neck is a vein and a white
cord. The cord is the pneumogastric nerve. The
vein is the jugular vein.

5. Insert the tube into the glottis and inflate the
lungs. Observe the swelling of the whole body, and
the inflation of the thin-walled air sac in front of the
breast bone. Other sacs can be seen just behind the
breast bone.

6. Find the ridge of bone along the breast of the
pigeon. This is the keel of the sternum.

7. Cut the large muscle of the breast loose from
the sternum. The muscle is the pectoralis major.
Loosen it all around except at the frontend. Find
the white cord (tendon) by which it is attached in
front. To what is it attached? What motion is pro-
duced when the pectoralis major is pulled?

8. Find the pectoralis minor, or subclavian mus-
cle, directly under the pectoralis major. Loosen it,
except in front. Trace the tendon to its insertion.
What motion is produced when the pectoralis minor
is pulled?

9. Scrape the flesh from the breast bone and from
the bones in front. Find the wish bone. It consists
of the homologues of two clavicles united. Remove
it and draw.

10. Find the coracoid bones, extending from the
sternum to the shoulder. What is the use of the cora-
coid bones and the clavicles?

11. Remove the sternum carefully, clean it, and
draw,

THE PIGEON. 107

12. Do you find a diaphragm?

13. Find the gizzard. Describe it.

14. The part of the intestine nearest the gizzard is
the duodenum.

15. In along loop formed by the duodenum, find
the pancreas.

16. Trace the intestine, tearing it loose from a
thin, transparent membrane (mesentery) that holds it
in place.

17. Find two very short side branches (ceca) near
the end. In some kinds of birds the ceca are very
long.

18. Find the cloaca, which is the widened termi-
nation of the intestine.

19. Find the glandular stomach, in front of the
gizzard. See the esophagus leading into it.

20. Remove the glandular stomach, gizzard, and
intestine. Examine the gizzard. Open it. Observe
its contents and its lining. Of what use is the giz-
zard?

21. See the liver. How many lobes? Has it a
gall bladder?

22. Can you find the spleen? This is a small red
body attached to the right side of the crop.

The Circulation.

1. Find the heart. Notice the thin sac (pericardi-
um) enclosing it.

2. Find the large artery, the aorta, running for-
ward from the heart. What branches does the aorta
give off, and where does each go? Toward which
side of the pigeon does the aorta turn after leaving
the heart?

3. The left subclavian is the name of the artery
which goes to the left wing. The left carotid is the
one which goes to the head. It branches off from the

108 NTRODUCTION TO ZOOLOGY.

left subclavian. Find also the right subclavian and
the right carotid. Trace the aorta backward, where
it is called the dorsal aorta.

4, Find veins leading the blood to the heart. The
one from the liver is the vena cava inferior. Find
two others coming from the front, right and left vene
cavee superiores.

5. Find the artery which carries the blood to the
lungs. This is the pulmonary artery. Find veins
which carry the blood back from the lungs. These
are pulmonary veins. How many are there?

6. Cut off all the arteries and veins as far from the
heart as youcan. Identify the parts of the heart.

7. Find the two auricles, right and left. What
tube enters each auricle?

8. Identify the two ventricles, right and left.
What arteries leave each ventricle?

9. Make a complete drawing of the heart and
blood vessels.

The Reproductive Organs.

1. In the back, find the ovaries in the female, or
two white oval bodies, the testes, in the male.

2. Find a tube leading from the reproductive
organs to the cloaca. In the female, this is called the
oviduct.

3. In the posterior part of the back, find the kid-
neys, two dark colored, irregular bodies. Find tubes
leading from the kidneys to the cloaca.

The Respiratory Organs.

1. Find the trachea, or windpipe. Describe its
structure. How many rings of cartilage has it?

2. Find the larynx, at the top of the trachea.

3. Find the two bronchial tubes, at the bottom of
the trachea.

THE PIGEON. 109

4. Find the syrinx, or lower larynx, at the place
where the two bronchial tubes divide. The song of
the bird is produced in the syrinx.

5. Inflate the lungs by means of a tube inserted
into the trachea. Are the lungs free, or attached to
the back? What holds them in place? What causes
air to go into the lungs?

ea

The Skull. t

1. Separate the head from the neck, and scrape
as much flesh from it as you can.

2. Find the large hole at the base of the skull
through which the spinal cord runs. This is the
occipital foramen.

3. In front of the occipital foramen, find a round-
ish, convex knob or surface. This is the occipital
condyle. Is there one, or more than one?

4. See how the lower jaw joins the skull. The
very small bone by which the lower jaw articulates
with the skull is the quadrate bone.

5. Find a slender bone along the lower edge of the
upper mandible. This is the jugal or maxillary bone.
Where is it attached at each end?

6. When the lower jaw is depressed, what effect
does the motion have upon the quadrate bone? Upon
the jugal bone? Upon the upper mandible?

7. Draw the skull, showing all the above men-
tioned parts.

8. Separate two or three vertebre from the neck.
Clean and draw them.

The Nervous System.

1. Find the spinal cord in the neck. Do you find
the roots of any nerves?
2. Look into the body cavity, near the backbone,

110 INTRODUCTION TO ZOOLOGY.

between the ribs, for nerves. How many pairs do
you find?

3. Find nerves leading from the spinal cord to the
wings, and to the legs. Howdo these nerves com-
pare in size with other spinal nerves?

4. Slice off the top of the skull and expose the
brain. Make out the following parts: the cerebrum,
in front, consisting of two lobes separated by a deep
groove; the cerebellum, undivided, behind ; the optic
lobes, at the sides, below the cerebrum and cerebellum.

5. Lift up the brain and see the optic nerves run-
ning to the eyes. Do they cross? Do they unite with
each other?

6. Draw the brain.

The Feathers.

1. Study one of the large wing feathers. The
hollow rounded part is the calamus, or quill. The ex-
panded part is the vane. The central portion of the
vane is the rhachis. The small divisions on each side
of the rhachis are the barbs.

2. Examine a few of the barbs. See the barbules,
interlacing between the barbs. These hold the barbs
in position.

3. Do you find any barbules on the down?

4, Draw a feather.

An Egg.

1. Note the shape, size, and smoothness of the
shell. Are the two ends alike?

2. Break the shell and examine the lining. Of
how many layers is the lining composed? In which
end is the air bubble?

3. Is the ‘‘ white ’’ all alike, or is there more than
one kind?

THE PIGEON.

111

4. Observe a thin membrane, the vitelline mem-
brane, around the yolk.

5. Notice two twisted strings, the chalaze, run-
ning from the vitelline membrane in the white.

6. In the yolk, notice the nucleus.

clear through?

Does it extend

7. In the nucleus, see the nucleolus.

Make a table showing differences between a pigeon

and a fish, thus :—

Fish. Pigeon
GONETING cts, ssa onsale teeiene bette cattenrnGni aul lew wionantmnare weg oa
APPCNdAPeS inca Ges aws leea nto esaes aileate eee Senses
RADIA bias eich ssa altn’ Wows coat cree sarge a all weg emeainedte ez eee 4%
Locomotion cxéi06 oc aeqis| ewes <x zeae petenias glee hacias ser eae eecaan
Aeartac escent cena cs leenmied no atts seyesrea sl) 2x2 s Made tea toe
Circulation eas %t2sssecleda steed wreteas alae 4S eMarascesae on aw s
Breathim@:. <tr i oasuine| saised seek eeglearedeace
PL OMA PON AUT UILG i ieiesis acs 3c sons cians dcecea Sea ess eynroucuntioaes thal, date nyathtasuatenavieerare b soath
PG ara ci sac ies diacene Gh dow ort | eae cia B astanie aaavmeatanutiee I cosh Bale neal ate teaes
Review Questions on the Pigeon.

1. What is the beak?

2. Of what is the beak composed?

3. How does the mouth open?

4. What is peculiar about the tongue?

5. Where are the nostrils?

6. Into what do the nostrils open?

7. What and where is the glottis?

8. How many eyelids?

9. Where is the third eyelid fastened?
10. What is there in our eyes that is homologous

=
we

to the third eyelid?

. Where are the ears?
. What is peculiar about the feathers around the ears?

INTRODUCTION TO ZOOLOGY.

. What is peculiar about the ear itself?
. Name the parts of the leg.

. Between what bones is the knee?

. Where is the heel?

. Is the tarsus feathered?

With what is the tarsus covered?

. How many bones, exclusive of the claw, in the

hind toe? Inner toe? Middle toe? Outer toe?

. Name the parts of the wing.
. What feathers grow on the hand? On the arm?

On the forearm?

. What and where is the spurious primary?
. How many bones in the forearm?

. How many bones in the hand?

. How many primaries has a pigeon?

. How many secondaries?

. What are the coverts?

. How many tail feathers?

. Where are the tail coverts?

. Where are the scapulars?

. How are the feathers arranged?

. What are pin feathers?

. What homologues of feathers are also found?

Where is the oil gland? What is its use?

. What isthe windpipe? Of what is it composed?
. Where is the crop? What is its use?
. What veins run down the neck?

What arteries run up the neck?

. What nerve runs up the neck?
. What are the air sacs? How many did you

count?

. What and where is the sternum?
. What bones are joined to the front end of the

sternum ?

. To what is the wish bone homologous?
. What and where is the scapula?
. What muscle moves the wing up?

ADDITIONAL FACTS ABOUT BIRDS. 113

. What muscle moves the wing down?
. What is a tendon?
. To what bone is the tendon of the pectoralis minor

attached? At what place on the bone is it
attached?

. Has the pigeon a diaphragm?
. How many ribs?
. What difference between the bones of the neck

and the bones of the back?

. What is the pericardium?
. What is the principal artery leaving the heart?

From which end of the heart does it go?

. In what direction does it turn?
. What is the first: branch of the aorta?
. To what organ does the left subclavian artery

carry blood?

. What is the first branch it gives off?

. What is the second branch of the aorta?

. To what does the right subclavian carry blood?
. What is its first branch?

. To what other organ does the aorta carry blood?
. What veins bring blood back to the heart?

. What tubes open into the cloaca?

. How many chambers in the heart?

. What and where is the occipital condyle?

. What and where is the quadrate bone?

. Name all the parts of an egg.

. Name all the parts of a feather.

Additional Facts About Birds.

Birds are distinguished from all other animals by

being almost completely covered with feathers. We
can see, however, that on some birds the tarsus is
covered with scales instead of feathers. So it seems
quite evident that in some way the feathers take the
place of scales. Feathers are therefore homologous

114 INTRODUCTION TO ZOOLOGY.

to scales. That is, the same thing which is devel-
oped on the fish as scales is developed on the bird as
feathers.

Among the feathers will be found hairs. The
hairs are scattered among the feathers, being clustered
together in some instances around the mouth and
ears. Since they have the same position as feathers,
we are compelled to believe that feathers and hairs
are homologous structures.

This covering of the body which may be devel-
oped as scales, feathers, or hairs, constitutes what
may be called the exoskeleton. It is composed of a
substance called keratin, one ingredient of which is
sulfur. A pigeon, then, has redlly two skeletons, an
exo- and an endo- skeleton, although when we speak of
the skeleton of a bird we always mean the endoskel-
eton.

The wings are highly specialized organs, adapted
for flight. The large feathers, the primaries, are ar-
ranged in such a way that the short barbs of one
primary overlap the longer and less stiff barbs of the
other side of the next feather. This arrangement
makes a firm surface for the downward stroke, but
allows the passage of air between the feathers much
more readily when the wing is rising.

The muscles that move the wing are very curious.
Two muscles, pectoralis major and pectoralis minor,
lying side by side, produce directly cpposite motions
of the wing when they contract alternately. The ten-
don of the pectoralis minor passes directly over the
end of the humerus, and is attached to the upper side
of the same bone. This constitutes a pulley, and
changes the direction of the motion. It pulls the
wing upward. The pectoralis major passes over no
pulley, so its contraction pulls the wing downward.

The pectoralis major is much larger than the pec-
toralis minor. This is readily associated with the fact

ADDITIONAL FACTS ABOUT BIRDS. 115

that it is the downward stroke of the wing, caused by
the contraction of the pectoralis major, which raises
and supports the bird in the air, while the action of
the pectoralis minor does nothing but bring the wing
into position for another downward stroke.

The strong, deep keel on the sternum furnishes a
place for the attachment of these muscles. In kinds
that do not fly, such as the ostrich, the sternum is not
keeled, and the pectoralis muscles are not strongly
developed. ,

No living bird has any teeth. The jaws are
encased in a horny beak. Some fossil birds,
among the earliest birds that lived, had teeth, and
rudiments of teeth have been found in some embry-
onic birds.

The heart is four-chambered, and the circulation
is double and complete. The aorta, instead of sending
off two branches, right and left, as in the frog,
bends to the right. That is, it retains only the right
branch. The bodily temperature is constant, and
about 104 degrees F.; so the bird is said to be warm
blooded.

The breathing is by lungs, which are attached to
the back. There is no diaphragm, but the movement
of the ribs and abdominal walls serves to enlarge the
cavity of the chest and so causes the air to rush into
the lungs.

Besides the lungs, the pigeon has a series of acces-
sory air sacs which serve not only to furnish more air
to the body, but to make it lighter in relation to its
size.

Everything about the bird seems to have reference
to its power of flight. Flying is the characteristic
motion of birds, and the body is built with especial
reference to that fact. The long bones are hollow and
without marrow. The bones of the skull are filled
with air spaces. Feathers are the lightest possible

116 INTRODUCTION TO ZOOLOGY.

covering, and the largest flying bird is much smaller
than the largest land or water animal.

The eggs of birds are remarkable for their very
large size in comparison with those of other animals.
The greater part of the egg consists of food for the
embryonic bird. The egg begins to divide at the nu-
cleus, as all other eggs do, but the planes of seg-
mentation do not extend entirely through the body of
the egg, as they do in the eggs of the frog and of some
other animals. The segmentation is confined to a
small portion of the egg which is called the germinal
disc, and the body of the bird is formed from the
cells thus produced. The remainder of the egg is
absorbed as food, or nourishment, by the embryonic
bird.

This kind of segmentation is called partial, or
meroblastic segmentation.

The usual method of incubation is for the bird to
sit upon the egg. The side of the egg upon which the
germinal disc, or white spot, lies is apparently of less
specific gravity than the opposite side. This is shown
by the fact that in about nine out of every ten eggs
that are broken, the germinal disc appears upon the
upper side, and it takes careful and persistent effort
to turn the yolk over so that the germinal disc will
not show. The germinal disc is upon the upper side
of the egg. This position brings it nearest the body
of the sitting bird, which is the source of warmth, and
this is the most favorable condition for the growth
of the embryo.

An air space is usually found in an egg. The air
space arises in the following way: When the egg is
laid, it is of the same temperature as the body of the
bird. It very soon cools, and its contents are thereby
contracted. The shell, however, being rigid, cannot
contract, so air is drawn in through the pores of the
shell. The air space is found in the large end, because

THE TURTLE. 117

this is the most porous portion of the shell, and here,
for some reason, the membranes are most easily sepa-
rated. Subsequent increase in the size of the air
space is due to the evaporation of water from the egg.

Some birds migrate. Their lives depend upon
obtaining a sufficient supply of food at every season
of the year. When the food of abird disappears upon
the approach of winter, as does the food of most
insect-eating birds, the bird is compelled to go to some
place where food can be obtained. Woodpeckers do
not necessarily migrate, for their food is obtained
from insects found in dead trees. These are quite
largely available all winter. Ducks and_ geese
must migrate from the north, for the water, to
which their habits of life adapt them, becomes frozen
over.

There are usually considered about eighteen orders
of birds.

THE TURTLE.

1. Chloroform the turtle. Cut off its head.

2. Examine the shell. The upper part is the
carapace. The lower part is the plastron. Of
how many plates is each composed? How are they
united?

3. Saw through the union of the carapace and
plastron? Cut the skin loose from the plastron, all
around, and remove the plastron.

4. See the stomach. Trace the intestine to the
cloaca.

5. Notice the heart in its pericardium. Usually
the heart will beat for an hour or two after the turtle
has been chloroformed and its head cut off.

6. Trace the aorta. Does one branch, or two, per-
sist? If two, which is the larger?

7. Look at the lungs. Is there a diaphragm?
How are the lungs held in place?

118 INTRODUCTION TO ZOOLOGY.

8. See the reproductive organs. If it is near the
breeding season, large eggs are likely to be found in
the ovaries.

9. See the large retractor muscle, by means of
which the head is drawn into the shell.

10. Observe the mode of attachment of the neck to
the carapace. How many vertebre in the neck?
Clean one and draw.

11. Examine the skull. How many occipital
condyles? Is there a third eyelid? Has the turtle
any teeth? What is the nature of the jaws?

12. Observe the fore leg. What is the covering
of the feet? How many toes on the fore leg?

13. Identify the scapula and the clavicle.

14. Study the hind legs. How many toes on each
hind leg? Howis the pelvis attached to the carapace?

15. Are there any ribs? Of what is- the carapace
composed? How many plates or bones can be counted
on the inside of the carapace?

16. How many bones in the tail? How is the tail
united to the carapace?

17. Of how many layers is the carapace composed ?
Is the outer layer of the same material as the inner
layer?

Make a table showing resemblances between a
pigeon and a turtle, as follows :—

jaws encased in a horny beak
no teeth
third eyelid (nictitating membrane)
tarsus scaly
Pigeon one occipital condyle
Turtle lower jaw articulates with the skull by means of a
quadrate bone
dorsal vertebrze consolidated
intestine opening into a cloaca
right branch of aorta the principal one

THE TURTLE. S19

Additional Facts About the Turtle.

Notwithstanding the very unlike appearance of
the pigeon and the turtle, an arrangement of their
resemblances shows that birds and reptiles are very
closely allied. So close is the relation between them
that Mr. Huxley puts birds and reptiles into one class,
which he calls Sauropsida. The resemblances are so
important that they seem explainable only on the hy-
pothesis that birds have descended from some form of
Reptilia, although not from turtles or snakes.

The most reptile-like or- |: Sa
ders of birds are extinct and
known only by their skele-
tons. The most birdlike W ¢
orders of reptiles are also “ad
extinct, so the living birds
and living reptiles are very un-
like each other. One of the
earliest birdlike forms that ever
existed is called the Archmop-
teryx. It has been found as a
fossil skeleton in some limestone
beds in Germany. The accompa-
nying figure shows how Mr. Shu-
feldt thinks it must have looked.
It is difficult to decide whether
a creature like this should be

called a reptile or a bird. (Afton SHUTELDTY:

The characteristic feature of the turtle is the shell.
This is composed of the vertebrae of the back, which
are solidified together; of the expanded and = con-
solidated ribs; and of the exoskeleton, which, in the
turtle, is developed as horny plates and consolidated
with the internal skeleton. The vertebre of the
pigeon’s back are also consolidated, but for a different

120 INTRODUCTION TO ZOOLOGY.

purpose. In the pigeon the consolidated vertebre
furnish a more solid support for the wings, while in
the turtle the consolidation of the vertebra into the
shell furnishes a protection for the animal.

The corpuscles of the blood are nucleated, and the
turtle is cold blooded.

The eggs of the turtle are large, like those of
birds, and contain much white surrounding the large
yolk. In some species of turtles, the egg has a calca-
reous shell, asin birds, while in others the shell is not
calcareous.

There are four orders of living reptiles :—

Chelonia—turtles.

Ophidia—snakes.

Lacertilia—lizards.
Crocodilia—alligators and crocodiles.

There are six orders of reptiles that are extinct.

The snakes and crocodiles represent the extreme
forms of the orders.

ZOOLOGICAL LABORATORY, NcGRAW HALL

CHAPTER IX.

THE RABBIT.

1. Examine the legs. Look at the soles of the
feet. How many toes on each foot? Which pair of
legs is the longer?

2. Note the length and position of the ears.

3. Observe the whiskers on the upper lip. Notice
the nostrils and the cleft in the upper lip.

4. Find the third eyelid, or nictitating membrane.
Compare it with that of the pigeon. Is it functional
or vestigial?

5. Notice the inside of the cheek.

Internal’ Structure.

1. Skin a rabbit and slit through the abdominal
walls as far forward as the diaphragm.

2. Identify the intestine the liver and the
stomach.

3. Examine the stomach. Notice its shape and
size. Find the cesophagus, entering it, and the in-
testine, leaving it.

4. How many lobes to the liver? Find the gall
bladder. Can you find a tube leading from the gall
bladder to the intestine?

5. The part of the intestine just behind the
stomachis the duodenum. Theirregular mass within
the loop is the pancreas.

6. Notice the mesentery. This is the thin mem-
brane which holds the coils of the intestine together.

121

122 INTRODUCTION TO ZOOLOGY.

Separate the intestine from the mesentery. Find
where the mesentery is attached to the body.

7. Notice the place at which the small intestine
sets into the large intestine. The part of the large in-
testine beyond this point is the cecum. How longis it?

8. Remove the intestine from the abdomen. Find
the dorsal aorta running along the backbone.

9. Find a branch of the aorta going to each kid-
ney—the renal arteries, right and left. Do both leave
the aorta at the same place?

10. Find a division of the aorta going to each hind
leg. These are the right and left common iliac arteries.

11. Find the vena cava inferior, running toward
the heart parallel to the aorta.

12. Find the iliac veins, coming from the hind legs,
which veins, by their union,form the inferior vena cava.

13. Can you find the portal vein, entering the liver?
This vein is formed by the mesenteric vein, the splenic
vein, from the spleen, and the gastric vein, from the
stomach.

14. Can you find the hepatic vein, from the liver,
emptying into the inferior vena caya?

15. Examine the diaphragm. The thin, transpar-
ent portion in the middle is the tendon. Of what is
the diaphragm composed? What is its use?

Organs of the Thoracic Cavity.

1. Cut through the ribs on each side and open the
thorax. Identify the heart and the pericardium en-
closing it.

2. Find the auricles.

3. Trace the aorta. Does it bend to the right or to
the left? What branches does it give off?

4. Identify the following arteries :—

(a) The right subclavian, carrying blood to the
right fore leg.

THE RABBIT. 123

(b}) The right and left common carotids, sending
blood to the head. They are called common carotids
because each divides into an external carotid, carry-
ing blood to the outside of the head, and an interna]

carotid, carrying blood to the brain and inside of the
head. From what artery do these spring? Do they
leave the artery separately or together?

(c) The left subclavian, carrying blood to the left
fore leg.

5. Trace the aorta until it becomes the dorsal
aorta, previously seen.

6. Find oneach side of the neck a large vein, the ju-
gular vein. Trace it towards the heart until it unites
with a vein from the left fore leg, the subclavian
vein.

7. The union of the jugular and the subclavian
veins forms the superior vena Coie Find one on

each side of the body.

8. Cut off the arteries and veins as far from the
heart as you can, and remove the heart and lungs
from the thorax. What holds the lungs in place?

9. Notice the trachéa. Find the larynx, at the top.
How many rings has the trachea? Do the rings go
entirely around? What is the position of the
csophagus, with reference to the trachea?

10. Notice the bronchial tubes. Where does each
lead? ;

11. Find the pulmonary artery, leading from the
heart to thelungs. Find where it branches to each lung.

12. Find the pulmonary veins, leading from the
lungs to the heart. How many?

13. Identify the right and left auricles and the
right and left ventricles. With which chamber of the
heart does each artery and each vein that you have
seen communicate?

14. Make a complete diagram of the circulation of
the rabbit.

124 INTRODUCTION TO ZOOLOGY.

The Head.

1. Remove the skin from the head. Below and
back of the ear, find an irregular pink mass, the
parotid salivary gland.

2. In the angle between the branches of the lower
jaw, find two roundish bodies, the submaxillary sali-
vary glands.

3. See the muscle which covers the back part of
each side of the lower jaw. This shuts the mouth.
Where is it attached? Cut it away.

4. Thoroughly clean the lower jaw and examine
the teeth. The front ones areincisors. Those farther
back are molars. How many of each kind in the
upper jaw? How many of each kind in the lower jaw?

5. How is the lower jaw attached to the skull?
Draw the lower jaw.

6. Find the occipital foramen, through which the
spinal cord passes into the skull.

7. In front of the foramen, find the two occipital
condyles. Thoroughly clean the first two vertebree of
the spinal column. The first one is the atlas, the
second one is the axis. How do they differ?

Interior of the Head.

1. Cut away carefully the top and back of the
skull, exposing the brain. Find two coverings, one
closely attached to the skull, the other covering the
surface of the brain. The first one is called the dura
mater, and the second one is called the pia mater.

2. Identify the cerebrum. Notice the groove be-
tween the two lobes.

8. See the band of white fibers connecting the two
lobes.

4. Identify the cerebellum, behind and under the
cerebrum.

THE RABBIT. 125

5. Find the medulla oblongata, which is the part
of the brain within the skull that is continuous with
the spinal cord.

6. In front of the cerebrum, find the two olfactory
lobes.

7. Lift up the front of the brain and see the cra-
nial nerves. Find the optic nerves and trace them to
the eyes. Do the nerves cross?

8. How many pairs of cranial nerves can you
discover?

Spinal Cord.

1. Cut through the vertebra, unroofing the cavity
in which the spinal cord lies. See the covering of the
spinal cord.

2. See the roots of the spinal nerves. Notice that
the nerves go off in pairs, a right and a left, and that
each nerve has two roots, an anterior and a posterior,
or upper and lower.

3. Find a ganglion, on the posterior root just be-
fore it joins the anterior one.

4. Inside the body cavity, between the ribs, look
for continuations of the spinal nerves. How many
pairs of spinal nerves can you discover?

5. Find the large nerves that go to the fore legs.
Notice the size of the spinal cord at the place in which
these nerves originate.

6. Find the large nerves that go to the hind legs.
The principal nerve down the leg is the sciatic nerve.
Trace it.

The Legs.

1. Separate from the body the entire skeleton of
the fore leg, including the shoulder blade. Is it con-
nected by a joint to the backbone? What holds it in
place?

2. Clean all the muscle away from the bones.

3. Identify and draw all the bones you can find.

126 INTRODUCTION TO ZOOLOGY.

4. See the ligaments which hold the bones
together.

5. See the cartilage which covers the ends of the
bones.

6. Feel the slippery surface of the end of one of
the large bones. Synovia, or joint water, renders it
slippery.

7. Find a lining over the bones, completely cover-
ing them. This is the periosteum.

8. Study the muscles on the hind leg. Separate
one muscle from all the others. Study it.

9. Notice the muscle sheath, a very thin, trans-
parent membrane over all the muscle.

10. Note the tendon, a tough white cord at the
end of the muscle. Find the place in which the ten-
don is attached tothe bone. The place of attachment
which is nearest the central part of the body is called
the origin. The attachment at the other end is called
the insertion.

11. Separate a small part of muscle into stringy
pieces as small as you can. The finest pieces into
which you can separate it are called muscle fibers.

12. A muscle fiber, when highly magnified, shows
short markings across it. These markings are called
striations, or strie. Voluntary muscles, or those
under control of the will, are all composed of striated
fibers. So is the heart, which is an involuntary mus-
cle. It is probable that striations are more closely
associated with the frequency and vigor of contraction
than with its voluntary or involuntary character.

Review Questions on the Rabbit.

1. What is the covering of a rabbit?

2. What is its color? Is this color an advantage?

3. Tell of the length and color of the tail. Is this
color of any use?

THE RABBIT. 127

In what direction do the ears point?

How many toes on the hind foot? On the front
foot?

What is peculiar about the soles of the feet?

What peculiarity has the upper lip?

Is there a third eyelid?

How many incisors in the lower jaw?

How many incisors in the upper jaw? How are
they arranged?

. How many molars in the right side of the upper

jaw?
How many in the right side of the lower jaw?

. Of what use are the whiskers?
. What two cavities in the body? What separates

them?

. What organs are found in the abdominal cavity?
. What are the digestive organs?

. What is the mesentery?

. What organs are in the thoracic cavity?

. Trace the aorta, naming all branches you have seen.
. From what part of the heart does the aorta spring?
. In what direction does the aorta bend?

. What veins carry the blood back to the heart?

. Name the branches which make up each vena cava.
. What part of the heart do the ven cave enter?
. What artery carries blood to the lungs?

. From what part of the heart does it spring?

. What veins bring blood back to the lungs?

. How many pulmonary veins enter the heart?

. Name all the parts of the heart.

. What is the pericardium?

. How many lungs? What is their function?

. What muscles are used in breathing?

. What tube carries air to the lungs?

. How many rings in the trachea?

. Of what are the rings composed?

. Do the rings go entirely around?

128 INTRODUCTION TO ZOOLOGY.

37. What are the bronchial tubes?

38. What is the larynx?

39. What are the parts of the brain?

40. Which is the largest part?

41. How many cranial nerves did you see?

42. Do the optic nerves cross?

43. Where is the spinal cord?

44. How many pairs of spinal nerves?

45. How many roots has each nerve?

46. On which root is the ganglion?

47. How many ribs has the rabbit?

48. What are the vertebrae?

49. How many vertebre has the rabbit?

50. What are the names of the first two vertebree of
the neck? ;

51. How many condyles?

52. Of what use are the condyles?

53. What shape is the lower jaw?

54. How is the lower jaw attached to the skull?

Make a table showing the differences between a
fish, frog, pigeon, turtle, and rabbit, thus :—

Fish. Frog. Pigeon. | Turtle. Rabbit.

Habitatic cc sen. eta nad lesen cantaa eaten oc calice «at dxasavallSaseusecens “| Psceseee crate
PHBE cans ns's sare csieceratevetesa: aeveondaedeel Geese Sarat lavarateee-evel oa tere cn av

NOIR gels) weenie ane. es be ry dla Sit ea eagerness dan ee ees
Temperature scotia ess leweinaaalevecess + (p44 powesl sca gels Andes
Blood corpuscles: sxco4) 2 |iis-ouds| coud ssas acess encaleoaee ges
COVELING:, sna c.dise yet (ied. aoadl oe dessa lh oan realseareadeu| vaca eees
COILS ees iieit oh e e eceisges aaatore | Sods Gato ces lua edepsnud) aie aps Wiese | aa os home
Quadrate bone ........].... wire sh, < avscncara Istecepas cual aid eee eed
REPLOCUCUHION aiscanecsretn d.nsd|ractscsialene,s\| nae Sa Eda [bd asapiasienneclers) acanasiyas oetansedetea
BBS © sesalacernatirnsautesianeieicg: 40 sheahatss ge ee ol see esa neeasns vnareganeh exe ll aveievargeseeeel| gy vactnchotels
TSUN ES Pp otoutalaccaneresrncas-e houmaniasial a avn aece
Dia Phra pM ies ve cnecieokce ee tiaal le eaeeteees
Nourishment of young. |........

THE RABBIT.

129

Make a table of resemblances between the fish,
frog, pigeon, turtle, and rabbit, as follows :—

Fish
Frog
Pigeon
Turtle
Rabbit

red blood

internal, bony, jointed skeleton
brain and spinal cord enclosed in separate bony cavity
two movable simple eyes

two pairs of paired appendages

jaws move vertically

An animal which has the characteristics enumer-
ated in this table is called a vertebrate.

Make a definition of a vertebrate.

predicate noun you must use?
From your table of differences between the ver-
tebrates you have studied, make a logical definition of

a mammal.
use?

What is the

What is the predicate noun you must

When you say ‘‘A mammal is a vertebrate,’ what

do you mean?

What is included in the term vertebrate?

Make a table of differences between a grasshopper
and a rabbit, as follows :—

Grasshopper.

Rabbit.

JaWS oss sorceress

Breathing.........-.
Appendages
Antenne

Nervous system

Position of nerves....

Reproduction
Body divisions

{ double nerve cord t
and ganglia ....
in same cavity as

j other organs ... t

ee

brain and spinal cord.
enclosed in a separate
bony cavity

130 INTRODUCTION TO ZOOLOGY.

Additional Facts About the Rabbit.

The rabbit is taken to represent the class Mam-
malia. All animals of this class nourish their young
on milk, which is secreted by the mammary glands.

The rabbit belongs to an order of mammals which
are called rodents. The name Rodentia is given to
this order because the animals are great gnawers.
Rats, mice, squirrels, beavers, etc., belong to this
order. There are four incisors in the upper jaw of
the rabbit, but one pair, which is very small, is placed
behind the other pair. The incisor teeth grow
throughout life, so that the part of a tooth that is
worn away by excessive gnawing is soon replaced by
growth at the base.

Rabbits have no canine teeth. In the dog, cat,
and other carnivorous animals, the canine teeth are
very large and are used for seizing prey. Such
animals invariably eat meat as a part or all of their
food.

If we knew nothing of the food of the rabbit, we
should judge from the absence of the canine teeth
that it did not eat meat, and did not prey upon other
animals.

Rabbits often do injury to fruit trees, by gnawing
the bark. When rabbits become very numerous,
they eat so much of the vegetation that other animals
find it hard to get enough toeat. In this way, rab-
bits have become a very great pest in Australia.

About 1860, a gentleman from England, who had
settled in Australia, thought what a nice thing it
would be to have some rabbits near his home, as he
formerly had in England. He sent to England for
a dozen pairs and turned them loose. They multiplied
sorapidly that the Australian government and Aus-
tralian farmers have spent millions of dollars in trying
to exterminate them. It is estimated that.the loss to

t

THE RABBIT. 131

farmers caused by rabbits in ten years in the single
province of New South Wales, was $15,000,000.

Likewise, in some parts of California, rabbits have
become a pest.

Any animal, no matter what it is, unless killed by
some other means than a natural death from old age,
will multiply so rapidly as to eat up all the food that
a country can furnish, and so exclude or drive out all
other animals that depend upon the same kind of food.
The rabbit is preyed upon by other animals, it is frozen
to death in winter, and it is starved in snowdrifts, or
when its food is all covered with snow; but the rains
in the spring afford, probably, the most efficient check
upon the number of rabbits in the greater part of the
United States.

Rabbits produce seven to nine young at a birth,
and usually in the early spring. The young are com-
monly born in a bed made in a shallow depression in
the ground. If a heavy, dashing rain comes about the
time that the young are in this form, it is very prob-
able that all or nearly all will be drowned.

Rabbits and other animals are subject to various
diseases which operate as checks upon their rate of
increase. The tapeworm is a very common parasite
among rabbits. In one lot of ten dozen rabbits exam-
ined by the writer, forty-two were found to be infested
with tapeworm. This, however, is a very large per-
centage to be so infested.

Sometimes, when an animal or a plant is carried
from one country to another, the diseases, enemies, or
other checks that prevented its rapid increase at home
are not carried with it. Being freed from the checks
that restrained it at home, it multiplies so rapidly as to
become a serious evil. Such is probably the case with
the gypsy moth mentioned on page 37. Such is the
case with the San Jose scale insect, which has been very
destructive to orange groves in California. In such a

132 INTRODUCTION TO ZOOLOGY.

case, the remedy is to importa check if that is possible.
This has been done in the case of the fluted scale,
Icerya purchasi. Certain lady bugs which preyed
upon it in its original home, Australia, were brought
to the United States, and the fluted scale no longer
threatens the welfare of the orange growing industry.

This tendency of an animal to increase faster than
its food can increase is called THe PRESSURE UPON
SUBSISTENCE. Since there cannot be food enough for
all, each animal may be said to struggle to get enough
to eat. The struggle, however, is not merely a strug-
gle for food. It is a struggle to survive, notwith-
standing all the checks upon multiplication of its num-
bers. This whole struggle,—struggle for food, struggle
to escape from enemies, struggle to live through dis-
eases, is called THE STRUGGLE FOR EXISTENCE.

It seems very evident that not all will survive.
Those that do survive are likely to be the individuals
that in some way are best adapted to overcome the
various difficulties they encounter: to escape from
their enemies, by flight, fight, or concealment; to
recover from disease or to escape contagion; to
gather more food or to live upon less. The fact that
those who do survive are best adapted to the conditions
under which they live, supports what is known as the
theory of THe SuRVIVAL oF THE Firrsst.

Additional Facts About Vertebrates.

In all the vertebrates that we have studied we have
found an internal, bony skeleton. There are some
animals which must be classed with the vertebrates,
in which the skeleton is not bony. In such animals
the skeleton is cartilaginous, and in the amphioxus,
which has been called the lowest known vertebrate,
the only indication of a skeleton is a cartilaginous rod
along the back which is called the notochord. The no-

THE VERTEBRATES 133

tochord is the precursor of the backbone, and is found
at some stage in the development of every vertebrate.

The amphioxus is a little animal, somewhat fishlike
in form, about 23 to 3 inches long, found along the
Atlantic coast of the United States.

When studying the grasshopper, we found that the
skeleton was chitinous and wholly external. In the
vertebrates the skeleton is wholly internal, except, in
some degree, in the turtle. The body of the grass-
hopper is segmented throughout, but there is no
indication of such segmentation in the body of the
vertebrate, except in the vertebre of the spinal
column, and it is probable that this segmentation is
not at all homologous to the segmentation of the skele-
ton of the grasshopper.

We found reason to believe that the jaws of the
grasshopper move sideways, because they are homolo-
gous to legs. No such homology can be traced
between the jaws of a vertebrate and the legs of a ver-
tebrate.

No vertebrate has more than two pairs of appen-
dages. A centaur, with the body of a horse, and the
head, shoulders, and arms of a man, is, of course,
a monstrosity. But the monstrous character goes
deeper than at first sight appears. An animal like
the centaur would necessarily have two hearts, two
sets of lungs, two diaphragms, and two sets of ribs.

It is well for us to consider the relative excellence
of the breathing apparatus of the grasshopper and the
rabbit. The grasshopper breathes through several
spiracles along the sides of the body, and the air is
carried in the air tubes throughout the body to the
very place where it is to be used. Thus is obviated
all necessity for blood as a carrier of oxygen. In the
rabbit, the air is taken into the lungs, to which place
the blood is also brought, carrying its load of CO,
and exchanging it for oxygen. The oxygen is thus

134 INTRODUCTION TO ZOOLOGY.

carried by the blood to the tissues where it is to be
used. It really seems as if the introduction of the
blood as a carrier, or ‘‘middleman,’’ between the oxy-
gen and the tissues where it is to be used is a rather
clumsy contrivance.

We have seen the third eyelid, or nictitating
membrane, in the pigeon and in the turtle. Itisa
very useful device to those animals, enabling them to
see, in some degree at least, while the eye is still pro-
tected. We have seen the same organ, modified, in
the eye of a rabbit. The same structure is very
apparent in the eye of a dog, or in the eye of a horse,
and to a less degree in the human eye. In the mam-
mals generally, however, the structure is not at all
useful. It is an organ such as is called a vestigial
organ. Vertebrates generally, and mammals in par-
ticular, show many examples of vestigial organs. In
the human body, that part of the intestinal cecum
which is called the vermiform appendix is not only
useless, but is a positive source of danger, being sub-
ject to a disease called appendicitis, which frequently
causes death.

A rabbit or a horse can move its ears. The mus-
cle to move the ears exists in every human being, but
only a very few people can move their ears. The
muscle is vestigial.

The only explanation that is at all probable for
vestigial organs is that sometime in the history of the
species they have been useful, or, at least, functional.
But in consequence of changed conditions they have
lost their usefulness, and as a result, either directly
or indirectly, they have lost their functions.

The farther along the path of development an
animal has proceeded, and the more highly special-
ized it has become, the greater the number of vestigial
organs we may naturally expect it to show.

CHAPTER X.

THE FRESH-WATER CLAM.

1. Notice the two ends of the shell. In what
respects do they differ?

2. The edge on which the two parts of the shell
are attached to each other is the dorsal margin.

3. On the dorsal margin, find a pair of eleva-
tions, one on each part of the shell. These are the
umbones.

4. Between the umbones, and extending from them
in one direction, find a smooth band, the hinge liga-
ment. What is its use?

5. Hold the shell with the dorsal edge upward,
the hinge igament toward you. When in this posi-
tion the end of the shell toward you is the posterior
end, the end away from you is the anterior end, the
part of the shell toward your right is the right valve,
and the part of the shell toward your left is the left
valve.

6. Notice the epidermis, covering the shell. The
lines running concentrically around the umbo and
extending over the entire shell are the lines of
growth.

7. Draw a dorsal view of the shell. Draw a side
view of the left valve.

Interior of the Shell.

1. Notice the color and the interior surface of the
shell. Can you see the lines of growth?
185

136 INTRODUCTION TO ZOOLOGY.

2. Notice one line near the edge, much deeper
than the others. This is the pallial line.

3. Examine the hinge teeth, near the umbo on the
right. Are there different kinds of teeth? Do you
find corresponding teeth on the left valve? What is
the use of these teeth? Draw.

4. Find a scar near the anterior end of the shell.
This is the place where the anterior adductor muscle
was attached. You may call it the anterior adductor
impression. Find asimilar scar, the posterior adduc-
tor impression, near the posterior end of the shell.
Can you find another muscle scar on the shell?

5. Draw the inside of the right valve.

Internal Structure.

1. Remove the left valve carefully. Find the
mantle, or pallium, which covers the entire body.
Where is it thickest?

2. Find the anterior and the posterior muscles.
What do these muscles do?

3. Find the siphons at the posterior end. In the
salt-water clam, the siphons are permanent and are
an inch or more long. In the fresh-water clam, these
siphons are formed by the folding together of the
posterior edge of the mantle. They are not perma-
nent, and are manifested clearly only in the living
clam. Examine the edges.

4. Carefully remove the mantle. Find the gills.
How many on the left side? Study their structure.
Draw.

5. In front of the gills, find the labial palpi. How
many? What shape? Draw.

6. Between the palpi, find the mouth.

7. Notice the foot. Which way does it point?

8. How are the gills attached to the body? To
each other?

THE CLAM. 137

9. Observe two chambers inside the mantle cavity.
The one containing the gills, body, foot, etc., is the
branchial chamber. The other one, which is above
the body, is the cloacal chamber.

10. Before taking the clam out of the shell, look
for the nervous system. On the lower surface of the
posterior adductor muscle, find a double yellowish
body, the visceral ganglia. Find nerves leading from
the pair. Draw.

11. Just behind the upper portion of the anterior
adductor muscle is a small ganglion, the left cerebral
ganglion. Find the short nerve connecting it with
the right cerebral ganglion. Draw.

12. Just below the body in front of the foot, find
two pedal ganglia. Draw.

13. In the cloacal chamber, just above the
body, find the heart. The intestine passes
through the heart, but has no communication with
it. In the live clam, the beat of the heart is
easily seen. Can you find one artery passing
forward and two passing backward from _ the
heart?

14. Trace the intestine until it opens into the
cloacal siphon. Does it go above or below the adduc-
tor muscle?

15. Beginning at the mouth, trace the intestine as
far as youcan. Some will trace its entire course.

Suggestive Questions.

1. How does the clam get food?

2. How does the clam move?

3. How does the water get into the cloacal
chamber?

4. Of what use are the siphons?

5. Does a fresh-water clam or a salt-water clam
close its shell the more closely? Why?

138 INTRODUCTION TO ZOOLOGY.

Additional Facts About the Clam.

The clam belongs to a branch of animals called
mollusks. The name is applied to them because of
their soft body, without any skeleton. The class to
which the clam belongs is called Lamellibranchiata,
and this name refers to the kind of gills it has. The
gill is thin, or flat, like a plate or the leaf of a
book. Formerly, animals of this class were called
bivalves, because of the two parts of the shell. Still
another name was Acephala, which means without a
head.

The fresh-water clam moves very slowly in the
sand at the bottom of a pond orriver. It stands on
edge, half imbedded in the sand. The foot, which is
very muscular, is pushed slowly out of the shell and
downward and forward into the sand. After it has
been pushed out into the sand until it is securely
fastened, a sudden retraction of the foot itself, aided
by two muscles (retractors) inside of the shell, shortens
the foot. The tip of the foot being securely fastened
in the sand, the body enclosed in the shell must be
drawn toward it. In this way the clam, by a sin-
gle impulse, may move itself one-half or one-third
its length. This movement leaves a furrow in the
sand, and fresh-water clams can often be discovered
by following along this furrow. In the same way,
when the animal chooses to do so, it can burrow down
into the sand, completely concealing itself.

In order to breathe, the animal must get a current
of water to flow over the gills. Since the gills are
never extruded, it is necessary that the water be taken
into the shell. The water enters the shell through the
lower, or incurrent, siphon. In the fresh-water clam,
the siphons are not permanent, but are formed merely
by the lapping together of the two edges of the man-
tle. The edge of the lower siphon is very sensitive to

THE CLAM. 139

touch, and the opening is always protected by small,
finger-like or fringe-like processes which fold over the
opening and protect the clam from the introduction of
grains of sand and other injurious substances. The
upper siphon is not so closed, but is usually quite
open, and the finger-like processes diverge from
the edges.

The water comes through the lower siphon into
the gill chamber. Here it bathes the gills. Each gill
consists of a double layer of vertical rods fastened
together by transverse fibers, and the whole surface of
the gill is covered by a layer of ciliated cells. The
gill of the clam is one of the easiest objects in which
to observe ciliary motion. It is this ciliary motion
which is the principal cause of the current of water
into the lower siphon.

Some. of the water that enters the gill chamber
passes between the vertical rods of each gill into the
space between the two layers. This water goes up-
ward between the two layers of the gill, into the cloacal
chamber. The water which does not enter the gill
passes forward over the palpi and in front of the
mouth, and upward into the cloacal chamber,
where it meets the water that has come through the
gills, and with it passes backward and out through the
upper, or excurrent, siphon.

In consequence of the very short siphons, the
fresh-water clam usually buries itself in the sand only
the length of the shell; but the salt-water clam, such
as comes into our markets, has siphons which may be
extended six or eight inches, thus permitting it to
sink much deeper into the sand and still keep its
siphons at the surface.

The food consists of very small particles of animal
or vegetable matter which are carried into the gill
chamber by the current that enters the incurrent
siphon. It passes around in front of the mouth,

140 INTRODUCTION TO ZOOLOGY.

where its presence is perceived by the palpi, and it is
taken into the mouth.

The valves of the fresh-water clam seldom fit so
closely to each other as do the valves of the salt-water
clam. The starfish is the principal enemy of salt-
water clams. It kills them by inserting its stomach,
which is a very thin membrane, into the space between
the valves, and then digesting the clam within its
own shell. The salt-water clam, then, must have a
shell that fits very tight, or it will be killed by the
starfish ; but there are no starfish in fresh water, so
the clam that shuts its shell tight has no advantage
in that respect over the one that does not shut its shell
tight.

‘i The principal danger to the fresh-water clam is
the possibility of having its valves torn apart when a
strong ‘current pounds it over the stones. The
mechanical device of the interlocking teeth, near the
umbo, is employed to guard against this danger.
Another cause of the death of many clams is their
stranding in shallow pools which afterward dry up
completely. This occurs especially in river bottoms,
when the water recedes after a freshet to its usual level.

The eggs of the fresh-water clam are carried for
some time in the outer gill and hatched there. A
gill that is carrying eggs may be known by its dark
color and swollen appearance.

The shell is closed by the two adductor muscles.
The shell is opened by the hinge ligament, which acts
somewhat like the case-spring of a watch, opening
the valves whenever the adductor muscles are relaxed.
Fresh-water clams are too tough to be edible.

THE OYSTER.

Oysters in the shell can readily be secured from
most markets.

THE OYSTER. 141

1. On the oyster shell, find lines of growth,
umbo, right and left valve. Are the two valves
symmetrical? Which is the larger? Which is
attached ?

2. Find the mantle, muscle, gills, palpi, heart,
foot, stomach, and siphon.

3. State differences between the oyster and the
clam.

4. State resemblances.

5. What drawings have you made?

Make a table of differences between the clam and
the oyster.

| Clam. Oyster.
WALVESs. 6cscsidoscius: 5-2-0. | isthe Baste hasten ous) | edad Ge eeu s cone De
MOCRCLOL MUSElES* 0). wencacea ewer data sued <u ill Stes h ea see Saw Lee eek
CONGO Mi se scese bie ool sseeaena oe Sores ake edocs aa Sal aoe seme Ree
POO tis 0: Secavepstn a atea'anel|ig aguas toe dbo g eae el Me ars aa Roe Sea Ne
TABLE OF RESEMBLANCES.

soft body; no skeleton

four lammellate gills
Clam no head
Oyster shell of two valves

valves closed by adductor muscles
body enclosed by mantle which secretes shell

The oyster differs from the clam essentially in the
fact that it is attached by one valve to some support.
This is correlated with the facts that the foot is rudi-
mentary, and that the shell is very rough. If the
clam had as rough a shell as the oyster, it would
move through the sand with much more difficulty.
This roughness of the shell, however, is of no disad-
vantage to the oyster.

142 INTRODUCTION TO ZOOLOGY. +

THE SNAIL.

The pointed end of the shell is the apex.

The large opening is the aperture.

The edge of the aperture is the lip.

Find the lines of growth, parallel to the lip.
Find the spiral groove, on the outside, running
to the apex. This groove is called the suture.

6. Observe the turns of the shell between the
grooves. These are called whorls.

7. The whorls, all taken together, excepting the
largest, or body whorl, constitute the spire.

8. The axis, around which the whorls are coiled, is
called the columella.

9. Hold the apex up, the aperture toward you. If
the aperture is toward your right hand, it is a dextral,
or right-handed shell. If the aperture is toward your
left hand, it is a sinistral shell.

10. If the snail has a lid to close the aperture, the
lid is called the operculum.

11. Break off the shell and see the body. Find
the foot, the head, the mantle, the tentacles, and the
mouth.

12. Notice the shape of the body. You may see
from the outside some of the digestive organs. The
liver is the largest.

Cra ae ae

‘The Live Snail.

1. WarTcH LIVE SNAILS crawling over the sides of a
glass jar. Can you see tentacles? Eyes?

2. See the mouth, as it opens and shuts. How does
the snail eat?

3. Can you find the opening through which air is
taken into the lung, or water into the gill?

4. How many kinds of snail shells can you
collect?

THE SNAIL. 143

Make a table of differences between the snail and
the clam.

Clam. Snail.

From your table of differences, make a logical
definition of a Lamellibranch.

TABLE OF RESEMBLANCES,

soft body; no skeleton
usually enclosed in a calcareous shell
body covered with a mantle which secretes the shell

Clam
Snail

From your table of resemblances, make a definition
of a mollusk.

Additional Facts About the Snail.

The foot of the snail, instead of being narrow
and plough-like, as in the clam, is flat, and adapted
for crawling over a smooth, hard surface. The
mouth opens in the foot, rather forward of the
center. There is an organ called the tongue, or
lingual ribbon, or odontophore, which moves
across the aperture of the mouth when the mouth
is open.

Most of our land and fresh-water snails eat vege-
table food, either algee or decaying vegetation, This
may be associated with the fact that the aperture is
entire, having no notch, or prolongation. Many sea
snails are carnivorous. The aperture of such a snail

144 INTRODUCTION TO ZOOLOGY.

is always notched or prolonged into a spout, and the
odontophore in such a case is long and narrow, and
is called aradula. It is capable of drilling or sawing
a hole through the shell of another mollusk.

The odontophore con-
ists of a membrane of
horny material, thickly set
with numerous curved
teeth. It passes over the
surface on which the snail
is crawling and rasps_ off
anything that the snail can
eat.

ODONTOPHORE OF SNAIL,

Most sea snails breathe by means of a gill, but the
greater number of land and fresh-water snails breathe
by a lung. Usually a snail that has an operculum,
or plate to close the aperture, is a gill breather. One
without an operculum is a lung breather.

Most snails have eyes, and in the case of land
snails the eyes are placed at the ends of eye stalks.
In the greater number of our pond snails, however,
the eyes are not on stalks, but are situated at the base
of tentacles.

Some snails, called slugs, are without any shell,
or have only a rudimentary shell which is concealed
beneath the epidermis.

Snails belong to a class called Gasteropods. The
name is given because the snail looks as if it were
crawling on its belly. They are also called univalvyes,
because the shell is in one piece.

THE EARTHWORM. 145

THE EARTHWORM.

1. Can you distinguish a head and a tail?

2. Has it a dorsal and a ventral surface?

3. Has it a right and a left side?

4. How many segments, or somites, can you
count? Are they all alike?

5. Observe the cingulum, or girdle, near the
anterior part of the body. How many segments does
it cover? How many segments in front of it?

6. If your earthworm is alive, watch it crawl.
Describe the action fully. Can it crawl backward?

7. If your earthworm is alive, see the blood in the
dorsal blood vessel. Is there a corresponding ventral
blood vessel?

8. Examine the first segment of the body. Note
the rounded lip in front, the prostomium.

9. Find the mouth.

10. Feel and see, on the ventral surface, little
bristle-like organs, the sete. How many on each
segment? Of what use can they be?

11. Find a delicate outer membrane covering the
body—the cuticle.

Internal Structure.

1. Pin the body, back upward, under the water,
on weighted cork. Carefully cut through the body
wall from the tail to the head. Pin out the sides of
the cut.

2. Find the septa, which divide the body cavity
into chambers. How many?

3. Can you find the dorsal blood vessel? What
branches does it give off?

4. Trace the alimentary canal. Distinguish the
following parts: the buccal sac, in the first three
segments ; the thick-walled portion, in segments 4-7 ;
the csophagus, in segments 8-12; the crop, in seg-

146 INTRODUCTION TO ZOOLOGY.

ments 13-16; the gizzard, in segments 17-20; the
intestine, the rest of the way.

5. In the floor of the body cavity, note the nerve
cord and gangha.

Cross Section.

1. The cuticle has already been seen. The cross
section shows the outer layer of muscles. This layer
is circular, and runs
around the body.
When it contracts,
it tends to diminish
the diameter of the
body; but by the
diminution in diam-
4) eter, the length be-
comes greater, and
.| the distance be-
.| tween the head and
tailis increased. If
the setze point back-
ward, as they ordi-
i narily do, the in-

CROSS SECTION OF EARTHWORM. crease in distance
ee Ween vie haas
e, alimentary canal; 4, setee; g, ventral and tail will drive
nerve cord; A, ventral blood vessel; 7, the setee at the pos-
reproductive organs. terior part of the
body into the ground, and so furnish an anchor
which prevents the tail from moying backward ;
hence, lengthening the body pushes the head forward.
When the head is pushed forward, the backward
pointing sete ship freely over the surface. Thus there
is a forward movement of the head, and no backward
movement of the tail.

2. The cross section shows also a layer of muscles in-
side the circular layer. This is a layer of longitudinal

Oo
DS

THE EARTHWORM. 147

muscles. Suppose the body is extended, as described
in the preceding paragraph. Now the longitudinal
muscles contract. The tendency is to shorten the dis-
tance between the head and the tail. The head tends
to be drawn backward, but by this movement the
backward pointing sete that are near the head are
driven into the ground, while those at the posterior
of the body move freely over the surface; hence the
tail is drawn forward. The result of these muscu-
lar contractions, alternately performed, is to send the
body forward. If the sete, however, are directed
forward, as they may be, the result of the same con-
traction is to send the body backward.

3. The cross section shows the intestine, the
dorsal blood vessel, and the ventral blood vessel; also,
the ventral nerve cord, lying below the ventral blood
vessel, with nerves extending to the muscles of the
body wall. The nerve cord seems to be composed of
three cords, or elements.

4. The cross section shows eight sete, arranged
in four pairs. Each pair has a muscle by means of
which it may be retracted or thrust out, and directed
forward or backward.

5. One group of reproductive organs is seen.
Both male and female reproductive organs are found
in every earthworm. The male reproductive organs
occur in some worms insegments 9, 10, and 11; the
female organs (ovaries), in segments 13 and 14. The
position of these organs varies somewhat with the
different kinds of worms. More than 35 different
kinds of earthworms occur in the United States.

The earthworm is hermaphroditic, although (as in
the case of red clover and of many other flowers) cross
fertilization is necessary. That is, the male principle
of one worm fertilizes the female principle, or egg, of
another worm. The eggs of the earthworm are laid in
capsules, each capsule containing six to eight eggs.

148 INTRODUCTION TO ZOOLOGY.

Additional Facts About the Earthworm.

We find in the earthworm no lungs, gills, or other
breathing organs. It is very evident that the worm
must breathe; that is, there must be an exchange
of CO, for oxygen. This exchange of gases takes
place directly through the skin. The skin is a thin
membrane which is kept moist by the conditions in
which the animal lives. It is in effect a thin, moist
membrane, with blood loaded with CO, on one side,
and with oxygen on the other. These are the only
conditions necessary in a breathing organ, and are the
conditions attained in the construction of lungs and

ills.

: This fact enables us to account for some of the
habits of earthworms. Earthworms seldom come out
of their burrows in the daytime, except when it is
raining. At such atime, they often appear in great
numbers and in unexpected places. Some people be-
lieve that they rain down. They neither rain down
nor are drowned out. The rain and moist atmosphere
enables them to move freely on the surface of the
ground without danger of suffocation. Often, at the
close of the shower, worms are stranded on pavements
or other places into which they cannot burrow, and so
perish.

Should earthworms come out of their burrows in
daytime when the air is dry, the skin would quickly
become dry and they would be in danger of perishing.
At night, the danger from this source is much less,
and this sufficiently accounts for their activity at night
and apparent quiescence in daytime. Although they
have no eyes, Mr. Darwin found reason to believe
that they could tell the difference between daylight
and dark, by means of the first two seements.

We take the earthworm to represent the branch of
Vermes. It is probably as good a representative as we

THE EARTHWORM. 149

can have, although no one worm can adequately repre-
sent the whole branch. In fact, it would perhaps be
better to break up the branch of Vermes into several
branches, because of the great difference between
members of the group. It seems as if the men who
defined the limits of the branches of the animal king-
dom had picked out the animals thatclearly belonged
to other groups, and then said, ‘‘We’ll call all the rest
of the animals worms.’’ There are commonly reck-
oned about ten classes of worms, all very different
from each other.

Some worms are round, as the earthworm is, and
some are flat, like the leech. Some have suckers
at one end orat both ends. Some have the mouth at
one end of the body, and some have it in the middle.
Some have septa between the segments, and some
have no septa. Some lay eggs, and some are vivip-
arous; that is, the young are born alive. This is
true of the vinegar worm, and of the trichina, a para-
site which infests pork. Some worms (Brachiopods),
have a shell, like a clam shell, and others have no
shell. In fact, mollusks themselves may be consid-
ered as only a highly specialized group of worms. It
is almost impossible, from a study of a sufficiently
varied number of specimens, to make a table of resem-
blances from which to derive a definition of worms which
will discriminate this branch from all other branches.

Most of the worms are aquatic, and the greater num-
ber live in the sea. This fact we would expect to be
true from their lack of breathing organs and consequent
necessity of keeping the body moist. Many worms are
parasitic, as the trichina, already mentioned, and the
tapeworm. The Gordius,or hair worm, which is quite
common, is parasitic in one stage of its existence.
The very common belief that the hair worm is a trans-
formed horse hair, is not only unfounded, but fails to
recognize that a Gordius has various complex and

150 INTRODUCTION TO ZOULOGY.

complicated organs and life processes that it is impos-
sible to think of in connection with the structure of
ahair. It would take a long while for a hair to get a
stomach, a nervous system, and reproductive organs.

Make a table of differences between the carthworm
and the caterpillar.

Caterpillar. Earthworm.

Jaws

Eyes

We see from this table that it is very incorrect to
speak of a caterpillar as a worm.

THE STARFISH.

The branch to which the starfish belongs has no rep-
resentative on the land or in fresh waters. Ifitis to be
studied, specimens must be procured from the seashore.

1. Find the arms. Find the disk, which is the
part of the body from which the arms radiate. Find,
on the upper surface, the madreporic body, which is
small and white orred. Notice alsothespines. Look
closely around the base of the spines for the pedicel-
laria. Draw the upper surface.

2. On the lower surface, look for the mouth in the
center. Are the spines around the mouth just like the
other spines?

3. In the middle of each arm, find the ambulacral
furrow, or groove. Find in this groove the ambu-
lacral suckers, or tube feet. How many? How ar-
ranged? ;

THE STARFISH. 151

4. Find the radiating nerve in each arm, between
the rows of tube feet. Trace it from the circum-oral
nerve ring around the mouth, to the eye-spot at the tip
of the ray, or arm.

5. The lower surface is called the oral surface.
The upper surface is the aboral surface. Draw the
oral surface.

6. Remove carefully the aboral surface. Find on
the inner surface of the part removed, in each ray, a
thin band, the extensor muscle. What is its use?

7. Find the hepatic czeca, which are the large,
brown, lobulated organs in each ray. The membrane
which holds them in place is the mesentery. Are the
hepatic ceca connected with the stomach?

8. Note the stomach, in the center of the disk.
How is it connected with the aboral surface? Find
the retractor muscles, which draw the stomach back
into each ray.

9. Find the reproductive organs, which are along
the angle of each ray. There is little difference in ap-
pearance between the organs of the male and the fe-
male starfish. e

10. Find the stone canal, which extends from the
madreporic body to the circum-oral water ring. From
the circum-oral water ring, trace the radial water tube
into each arm.

11. The radial water tubes carry water into the
ampulla, or little sacs, which lie in the floor of each
ray. What is the relation between the ampulle and
the tube feet? Are the ampulle that are near the
mouth like the other ampullee?

12. Examine the plates which constitute the frame-
work.

Facts About the Starfish.

The starfish represents the branch of Echinoderms.
It is named from a thick skin which is beset with

152 INTRODUCTION TO ZOOLOGY.

spines. The name means hedgehog-skinned. In the
sea urchin, the spines are longer and the appropriate-
ness of the name is more clearly manifested.

We meet an entirely new fact in the study of the
starfish. There is neither head nor tail, nor is there a
right and a left side. We could divide it into five
parts, each part containing one arm, and the parts
would be approximately cquivalent to each other ;
but the parts, or arthromeres, are not arranged seri-
ally, one behind another, as are the segments in a
grasshopper or an earthworm, but they radiate from
a common center. From this fact, animals of this
branch were formerly called Radiates.

An animal that has a right and aleft side which are
approximately equal to each other, is said to be bilat-
erally symmetrical. Bilateral symmetry is the corre-
spondence between the right and left sides. All the
animals that we have previously studied have been
bilaterally symmetrical, except the oyster and the
snail. In these instances the symmetry is obscured.

The starfish is not bilaterally symmetrical, although
it is possible to draw a line through the madreporic
body that shall divide it into two corresponding
parts. The bilateral symmetry is subordinate to the
radial arrangement.

The stomach of the starfish is quite voluminous,
and is capable of being thrust out of the mouth and
wrapped around an object which it wishes to digest.
It is very thin, and can be insinuated into a very
small crack between the valves of a clam or mussel
or oyster, and these are the animals which constitute
the principal prey of a starfish. The intestine is very
short, and while it is possible to demonstrate that it
has an external opening on the aboral surface, such
opening is not readily apparent.

We are introduced in the starfish to an entirely
new method of locomotion. It is a hydraulic, or

REVIEW OF CLAM, SNAIL, ETC. 158

water-pipe system, by means of tube feet. The whole
water-pipe system is filled with water which enters
through the madreporic body, passes through the
stone canal, through the circum-oral water ring,
through the radial water tube into the ampulle.
Here the contraction of little muscles forces the water
into the tube feet, extending them to their full length.
When the tip of one of the tube feet is pressed against a
flat surface, the lifting of the central portion of the
disk at the tip creates a vacuum which fastens that
foot to the surface. As the tube foot then shortens,
the ray to which it belongs is drawn closer to the
point of attachment. By the action of many tube
feet, the starfish progresses, although it moves exceed-
ingly slow.

The starfish has the power to reproduce lost parts
in avery marked degree. If all of the rays except
one be pulled off, the starfish will still live, and it
will soon reproduce the missing rays.

There are no specialized breathing organs. The
water-pipe system performs the function of res-
piration.

The pedicellariz are small, pincer-like organs sur-
rounding some of the spines on the aboral surface.
Their function is not fully known.

Review of Clam, Snail, Earthworm, and Starfish.

THE CLAM.

What are the valves?

How distinguish the right and the left valve?

What is the umbo?

What is the hinge ligament?

What is the mantle?

What are the palpi?

How many gills has the clam? Explain their
structure.

ST Ou NS

INTRODUCTION TO ZOOLOGY.

What are the siphons?

. What are the adductor muscles?

What closes the shell?

. What opens the shell?

How does the clam get food?

. Where is the heart?

What and where is the cloacal chamber?

. What causes the current to go over the gills?
. How does a clam move?

Tue SNAIL.

. Define these parts of a snail: spire, whorl, apex,

aperture.

. Distinguish between right- and left-handed shells.

. What is the odontophore?

. How does a snail crawl?

. How distinguish a lung-breathing snail from a

gill-breathing one?

. How distinguish a flesh-eating snail from a vege-

table-eating one?

THe EartHworm.

. How does an earthworm breathe?
. How does an earthworm crawl? What muscles

does it use?

. What are the sete? What is their use?
. What are the reproductive organs?
. Why does the earthworm come out of the ground

during a rain?

. What is the cingulum?

THE STARFISH.

. How many arms has a starfish?
. What is the madreporic body? The stone canal?

What are the tube feet?

. Describe the water vascular system in full.

FRESH-WATER HYDRA. 155

32. Describe the nervous system.
33. Describe the stomach.
34. How does a starfish move?

FRESH-WATER HYDRA.

Fresh-water hydras may be found in almost any
pond, and almost any time in the summer. They are
too small to be studied satisfactorily without a micro-
scope, but can readily be seen with a hand lens, or
with the unaided eye.

1. Observe the size and the shape of the body.

2. Notice how the body is fastened to the support
on which it rests. This end of the body is the foot.

3. Observe the tentacles. How many? How
arranged? Are they smooth or warty? The mouth
is in the center between the tentacles.

4. The rounded prominence upon which the mouth
is situated is the hypostome.

5. Perhaps a bud may be seen growing from the
side of the hydra.

The hydra is the only
fresh-water representative
of a large branch of ani-
mals.

The branch is called
Ceelenterata, and includes
the Hydroids, Jelly fishes,
Corals, and many other
forms. It has no respira-
tory apparatus, no nervous
system, no heart or blood,
no stomach or digestive ap- FRESH-WATER HYDRA.
paratus. It has a perma-
nent body cavity, into which food is taken, and in
which it is digested, but the body wall itself acts as the
stomach. There is no separate stomach or intestine.

156 INTRODUCTION TO ZOOLOGY.

The hydra has a special provision for capturing
small animals which constitute its food. Certain cells
in the tentacles are provided with a coiled, spring-
like thread terminating in a harpoon point. When a
small animal like Cypris or Daphnia comes near the
tentacles, the little harpoons dart out from the nemat-
ocysts, or lasso cells, and stick into its body. This
paralyzes the animal, which is then drawn by the
tentacle to the mouth.

The hydra is a notable example of the ability to
reproduce lost parts. It may be cut into two pieces,
and each piece will become a hydra. It may be
turned wrong side out, and what was before the
external surface will take on the function of digestion.
If all the tentacles are cut off, new ones will grow out.

Hydras reproduce by budding, and by eggs. In
the case of budding, a small bud grows out on one
side of the body, which gradually develops tentacles, a
mouth, and a body cavity. Finally it separates from
the parent and attaches itself to another support.

Hydroids are very abundant in shallow water along
the sea shore. They look like plants, branching
freely, and each branch being tipped with a flower-
like body, somewhat similar to the hydra. All the
hydranths, or hydra-like bodies, that grow from a
common stem constitute a colony of individuals
which are dependent upon each other. What one
eats, nourishes all. In a case like this, what shall we
call the individual? Is it the single hydranth, or is
it all the hydranths that grow from a common stem?
The budding of the hydra manifests the same thing.
If the young hydra did not separate from the parent,
should we have one individual or two? It is not
always easy to tell what constitutes an individual.

Hydroids manifest the phenomenon of alternation
of generations. Some hydroids give rise to jelly fishes,
and the eggs laid by some jelly fishes produce hydroids.

FRESH-WATER SPONGE. 157

FRESH-WATER SPONGE.

Fresh-water sponges may be found in clear water
in most parts of the United States. They grow
attached to submerged logs, stones, or stems of bushes.
One of the most common forms is Myenia fluviatilis.

1. Observe the sponge mass as a whole. Notice
its lack of definite shape.

2. See the large openings in the surface of the
sponge. These are the oscula, or excurrent pores.
The currents of water come out of these pores.

3. See the clusters of spicules around the oscula.
Observe also the pointed spicules projecting above
the surface.

4, Cut through the sponge and look at a cross sec-
tion. Is there more than one layer of sponge sub-
stance? Does the sponge grow year after year?

5. Lookin the substance of the sponge for little seed-
like bodies. These are gemmules, or reproductive bodies.

6. Where are the gemmules? Do they form a
layer at the base? Are they scattered through the
substance of the sponge?

7. Examine the sponge as well as you can for the
spicules.

8. Observe the color of the sponge. Is it green?
Did it grow in the sunlight?

9. Spicules of a sponge may be separated from the
sponge substance by boiling first in sulphuric acid,
then adding, cautiously, nitric acid. The acid may
be removed by adding much water and allowing it to
settle, and repeating this process until all the acid
has been washed away.

Commercial sponges consist of the skeletons of
certain kinds of marine sponges. The fibers of these
skeletons are composed of a substance called spon-
giolin, which is very much like chitin. Spongiolin is
found also in fresh-water sponges, but it is small in

158 INTRODUCTION TO ZOOLOGY.

amount and only sufficient to hold together the spicules,
which are very numerous.

There are three kinds of spicules in a fresh-water
sponge: skeleton spicules, dermal spicules, and gem-
mule spicules. :

Microscopic Objects.

The skeleton spicules are the
largest and are arranged in
filaments which constitute the
skeleton. A cross section of
one of these skeleton filaments
will show the cut-off ends of
three or four spicules, with a
cementing material of spongi-
olin. In some instances, at
least, these spicules are hollow.

SPICULES OF FRESH-WATER SPONGE.

Usually, the skeleton spicules are slightly curved,
and more or less covered with spinous processes.
They are arranged in filaments of three or four
spicules lying side by side and with their ends over-
lapping the ends of succeeding spicules, all held
together by spongiolin. The filaments extend from
the base of the sponge to the surface.

The skeleton filaments furnish the support for the
cells which constitute the body of the sponge. These
cells are arranged so that each one constitutes a part
of the wall of a small chamber which communicates
with one of the canals whose external openings are
the excurrent pores.

The entire sponge is covered with an epidermis, in
which are embedded dermal spicules, usually smaller
than the skeleton spicules.

FRESH-WATER SPONGE. 159

The water goes through numerous small holes in
the epidermis, into a subepidermal chamber. It then
filters throughout the sponge, bathing every cell, and
finally passing out through the excurrent canals. It is
caused to move in the sponge by cilia, one of which is
found in every sponge cell that lines one of the canals.
By this moyement of the water, food and oxygen are
brought to each cell.

The gemmule consists of a
mass of granular protoplasm
surrounded by a thick wall in
which are embedded many
spicules arranged radially.
These gemmule spicules are
often somewhat spool shaped,
or like an axle with a wheel
at each end. There is always
an opening from the inside
of the gemmule through the
wall.

CROSS SECTION OF GEMMULE OF FRESH-
WATER SPONGE
(HETEROMYENIA ARGYROSPERMA),
The spicules are siliceous; that is, they are com-
posed of about the same material that glass is made
of. Consequently, acids do not affect them. Most
marine sponges have calcareous spicules, but in all
fresh-water sponges the spicules are siliceous.

Additional Facts About the Sponge.

The fresh-water sponge has no definite shape. Its
shape is determined by its rapidity of growth in any
given direction. It has no mouth, no body cavity,
no stomach. It can scarcely be called an individual,
but is a mere aggregation of cells. Each cell breathes
for itself, takes its own food, and does just what every
other cell does.

160 INTRODUCTION TO ZOOLOGY.

The sponge is usually colored more or less green.
The color is due to the presence of the same coloring
matter that is found in leaves. It is chlorophyl, and
uses up carbon dioxide, setting free the oxygen. It
is probable, however, that the chlorophyl is not a
part of the sponge itself, but is due to some vegetable
organism that finds a lodgment among the sponge
cells,

' All fresh-water sponges die in the winter and
nearly all disintegrate. Myenia fluviatilis, however,
is firm enough to withstand disintegration, and in the
spring the old sponge furnishes a substratum for a
new growth from gemmules.

PROTOZOA.

One of the characteristics of the Protozoa is that
they are too small to be studied without a microscope.
However, some of them are large enough to be recog-
nized by the unaided eye or by the use of the simple
lens.

The bell animalcule is exceedingly common
in ponds and ditches. The body is bell shaped
and is attached by a slender stalk to some sup-
port. The rim of the bell is surrounded by a
fringe of cilia which by their vibration produce
currents of water that bring particles of food to the
mouth.

The cilia are borne on a ridge which constitutes
the rim of the bell. This ridge is called a peristome.
The mouth is within the peristome, but at one
side.

When a number of food particles have been accu-
mulated by the vibration of the cilia, the bell and the
stalk are suddenly and strongly contracted. The
stalk is very much shortened by being thrown into
five or six spiral coils. The cilia fold inward, the

PROTOZOA. 161

rim of the bell is drawn quickly together, the bell
becomes almost spherical, and by this action the food
is forced downward into the mouth. There is no
stomach or hollow body cavity. The food is merely
crowded into the body mass, as a stone can be crowded
into a lump of dough.

Microscopic Objects.

VORTICELLA. CARCHESIUM.

Vorticella proper has only one bell on one stalk.
The stalk does not branch.

In Carchesium, the stalk branches and each
branch bears a bell at its extremity, the whole colony
looking like a tree with a flower bell at the tip of
each twig. The bell and the stalk are both con-
tractile.

In Epistylis, the stalk branches as in Carchesium.
The bell, however, is somewhat more elongated, and
the stalk is not contractile.

Usually, in the body of the bell, several food
masses may be found which are readily distinguish-
able by their color, and aclear, transparent body may
be seen which, at intervals of half a minute or more,
gradually contracts and disappears and soon reap-
pears. ‘This is called the contractile vesicle.

162 INTRODUCTION TO ZOOLOGY.

The Stentor is called
the Trumpet animalcule,
and is somewhat larger
than the vorticella. It
is frequently seen in
large numbers. In all
essential respects it is
much like the vorti-
cella, haying the ciliated
peristome, food balls,
and contractile vesicle,
and ingesting food in the
same way. It has no
stalk, but, while feeding,
attaches itself to some support by means of the small
end of the bell, or trumpet. When so attached, the
body elongates, thus giving the trumpet appearance,
and the wide end of the trumpet can be turned in
any direction. When not attached to a support, the
body is U-shaped in section, and swims about freely
by means of cilia which cover the surface of the body.

These cia are much [ = =
smaller than those upon | Z |
the peristome.

The Paramecium | / nN |
may be found in water
that has become foul by |
the decay of animal or
vegetable material. \

A jar of water in |\
which a clam has been | \ i,
left to die is sure to be Y
a very prolific source of x e
Parameecia. ————

From its shape, the
Paramececium is called the shpper animalcule. It is
ciliated all over its body, and swims about freely.

STENTOR.

|
|
|
|
|

PARAM(ECLUM,

PROTOZOA. 163

It has a mouth, which is situated at the extremity
of a groove running somewhat spirally from one end
of the | body about two-fifths of the way to the other
end. The food balls
and contractile vesicles
described under vorti-
cella are seen here.

The paramececium,
stentor, and vorticella
are among the largest
and most. complex of
the Protozoa. The
Amceba is one of the
sunplest. It is fre-
quently found crawl-
ing in the ooze at the
bottom of a pond, or
in mud that has been
taken from a pond. It
is amass of naked protoplasm, which seems to flow
along the surface of the glass slide on which it is
placed for observation.

A small stream of protoplasm will flow out in one
direction and the rest of the body will apparently
flow in the same direction and join the stream ; other
streams, that had previously started to flow out,
will flow back and join the body, and all will flow in
the one direction until the body has moved its
position.

If a particle of food is found in the way, the
body merely flows around it, enveloping it, and if
part of the substance that has been enveloped is
found to be indigestible, the body flows away from
it and leaves it.

There is no head, no tail, no definite shape, no cilia,
no mouth. Food particles are usually seen enclosed
in the body, and a nucleus appears in most amcebee.

AMCEBA.

164 INTRODUCTION TO ZOOLOGY.

A table of resemblances among the vorticella,
stentor, parameecium, and ameeba will show the fol-
lowing :—
each consists of a single animal cell
composed of protoplasm
ingest food in solid particles

Semtieel9 exchange COg for oxygen
Stentor :
- aquatic
Paramcecium
each has a nucleus
Amoeba

are very small
exhibit self activity
multiply by fission

This gives us a concept of a Protozoan. A Pro-
tozoan is an animal that consists of a single animal
cell, is composed of protoplasm, etc.

The Protozoa constitute a very large and important
branch of animals. In number of individuals at any
one time, they probably exceed all other animals
taken together. In degree of complexity, there is
perhaps as much difference between the simplest Pro-
tozoan and the most complex Protozoan as there is
between the simplest and the most complex animals
of any other branch.

It is very interesting to observe the change that
has taken place in the ideas of men concerning ani-
mals. The first division of the animal kingdom was
into two groups, the Vertebrates and the Invertebrates.
But it was early discovered that among the Inverte-
brates were several groups entitled to equal rank with
the Vertebrates, so a division into four groups was
recognized: Vertebrates, Articulates, Radiates, and
Mollusks. Still further study showed that Articulates
should be separated into Arthropods and Vermes.
Then the sponges were recognized as animals, and
the Protozoa were discovered; also, the Coelenterata
were separated from the Radiates.

PROTOZOA. 165

The Protozoa multiply by fission; that is, by di-
vision beginning at the nucleus. The body separates
into two parts which are approximately equal in size
and appearance. In this case, which is parent and
which is child? Which is the older and which is the
younger? Are both the offspring, or are both the
parents? If one is as old as the other, both must be
as old as the first one, because the first one has not
died. There is no dead body. It is possible to carry
this process on in thought for a thousand generations
without a single protozoan having died a natural
death. In fact, there seems to be no provision for
natural death among the Protozoa. Practical immor-
tality is a characteristic of Protozoa. Of course, it
is understood that Protozoa may be killed. They
may be eaten by other animals, may dry up, they
may be killed in a thousand ways, but in every case
this is an unpremeditated and unnatural end. Pro-
tozoa do not lay eggs. An egg is a single animal
cell, but a protozoan itself is a single animal cell. If
the protozoan were to produce an egg, it would be
merely dividing itself into two cells. That is what
occurs, but the two cells are alike, and one is no
more an egg than the other. Neither one is an
egg unless it is capable of developing into a more
complex structure. But an egg would not need to
undergo development to become a one-celled animal.

A protozoan, such as a paramecium, moves, but
it has no muscles. It breathes, that is, exchanges
COg for oxygen, but it has no lungs or breathing organs
of any kind. It digests, but it has no digestive organs.
It seems to feel, but it has no nervous system. It has
no skeleton, and of course it has no heart or blood, for
it is so small that no carrier is needed to convey ma-
terial, such as the blood carries, from one part of the
body to the other.

The explanation seems to be this, and this will fur-

166 INTRODUCTION TO ZOOLOGY.

nish an explanation also for the cells that constitute
the different organs of our own bodies. The single
cell of the paramcecium is capable of performing all
the above named functions. When it contracts, it is
exercising the function of a muscle cell, and it is a
muscle cell. When it digests, it is a digestive cell.
When it respires, it is a respiratory cell. The muscle
cell of the human body may be thought of as a cell,
like the protozoan cell, whose contractility has been
very much intensified and all other properties very
much diminished or held in abeyance or entirely lost.
So with a nervous cell. Its nervous character has
been very much -intensified and its contractility and
other properties entirely lost. The protozoan cell is,
as a cell, quite undifferentiated in its functions.

Make a table showing resemblances between para-
mecium, sponge, hydra, starfish, earthworm, clam,
grasshopper, and rabbit. ;

Paramoecium
Sponge

Hydra
Starfish exchange CO for oxygen

self-active movement

See eoen ingest food in solid particles

Clam
Grasshopper
Rabbit

From the above table, make a definition of an ani-
mal. What is your predicate noun?

We are not able at this point to make a table of
differences between animals and plants. It is very
doubtful whether the above characteristics would
completely discriminate an animal from a vegetable.
But this is the best that we can do until we study
plants. Let us call these characteristics animal
characteristics.

167

PROTOZOA.

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poo Teurds
pue ureiq
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= ‘sesepued
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SUvsIO
=> = SUITIVEI,
pezteroeds
= a — Arqgeuuss
a a = TRL} RTI
wieysds sno
-AIOU JOUTY
— = = = -SIp ‘SUeVZ.10
OATJSOSIp
eqeredes
= a = = cs AYTABO
~~ = =a _ = Apoq Moypoy
s33e Aq
= = = = = = sonpordat
{s[jeo AueuL
= ae ay a = = SOTISTIOJOR
e i = i _ _ = -IBYO [VUILUB
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SMOT[OJ SB

‘sTRUITUR Jo SdNOIS UOIEYIP It} OF SURSIO Jo VOTJIPPL OY} SULMOYS O[qeq B OYLIAL

168 INTRODUCTION TO ZOOLOGY.

An examination of the foregoing table shows us
what is meant by a more complex structure. In gen-
eral, each animal named in the table possesses the
positive characteristics of the several animals preced-
ing it and some special peculiarities of its own.

We are ready also from a study of this table to
make a logical definition of each branch; e.g., an
Arthropod is an animal that iscomposed of many cells,
has ahollow body cavity and separate digestive system,
is bilaterally symmetrical, has specialized breathing
organs, jointed appendages, and an exoskeleton.

Compare this definition with the one derived from
the table of resemblances on page 77. Have we
learned anything about the grasshopper since we
ceased studying it?

GENERAL REVIEW TOPICS.

Define Ontogenetic series.

Define Phylogenetic series.

Define Taxonomic series.

What is a notochord?

What is meant by homologous organs?

What is meant by bilateral symmetry?

What is radial symmetry?

What is a parasite?

How many methods of breathing have you found?
10. What is the essential process in breathing?

11. What is the essential organ in breathing?

12. How many methods of locomotion have you found?
13. What is meant by protective resemblance?

14. What is meant by mimicry?

15. What are warning colors?

16. What classes of animals have no nervous system?
17. What are vestigial organs? Give examples.

18. What methods of escape from their enemies do
animals employ?

OID OU 8 pO

GENERAL REVIEW TOPICS. 169

. What different kinds of covering have animals?

What is meant by metamorphosis?

. What are the principal groups in classification?
. What is von Baer’s Principle?

. What is meant by Natural Selection?

. What is meant by The Survival of the Fittest?
. What animals are useful to man? Z
. What animals are injurious to man?

State the rules for naming animals.

. What methods of reproduction have you found?
. What is parthenogenesis? What is hermaph-

roditism?

CHAPTER XI.

COLLECTING AND PRESERVING MATERIAL,

WITH SUGGESTIONS UPON ITS MANAGEMENT IN
THE CLASS.

The following chapter is designed to aid teachers
and pupils in collecting and preserving material for
class use. It is given as the.result of ten years’ expe-
rience with large classes, during which many devices
have been tried and many failures recorded. Every
device suggested here has been successfully employed.

GRASSHOPPERS.—About five grasshoppers will be
needed for each pupil in the class. These are best
collected in the early fall. The large Melanoplus dif-
ferentialis is easily collected in some places. An in-
sect net will usually be needed to collect them. The
grasshoppers should be killed by dropping them im-
mediately into a bottle of alcohol. They should after-
wards be transferred to such jars as Mason fruit jars
and kept in strong, clear alcohol.

CrickEets.—One for each pupil in the class will be
sufficient. They should be searched for by turning
over boards, stones, logs, and bunches of grass. They
can be captured by hand or by anet. They should be
preserved in alcohol, in the same manner as grass-
hoppers.

Katypips.— Sometimes they can be obtained around
electric lights. Usually they can be captured on low
bushes, such as willows, or in the meadow grass. In
general, all insects are most satisfactorily preserved in
strong alcohol.

170

COLLECTING AND PRESERVING MATERIAL. 171

WALKING sTICKs can be found in most places in the
United States on low bushes. Sometimes they will be
found very abundantly over a limited area, as on a sin-
gle tree or a small number of trees. No net is needed
for their capture.

BUTTERFLIES are usually plentiful over flowers or
in a clover field. Occasionally the Anosia are in very
great numbers for two or three days ata time. They
should be killed in a cyanide bottle, or by pouring a
few drops of chloroform or gasoline along the sides
of the abdomen. They should be preserved dry. A
piece of paper about five inches square is folded cor-
nerwise, one of the edges turned over, and the butter-
fly dropped in. A fold of the other edge closes the
triangle. Forty-eight hours before the butterflies are
needed for use the paper triangles containing them are
sprinkled heavily with water and placed in a tin box
with an air tight cover. The dried tissues will then
relax and the butterflies will be as useful as if freshly
caught. It will be found necessary to raise caterpillars
to obtain chrysalids, although in some places cocoons
of such moths as Cecropia may be cut from the trees.
Caterpillars are also to be preserved in strong alcohol.

BEETLEs may be found by turning over logs and
stones. Some kinds, such as Harpalus, are frequently
found in great numbers under electric lights. Grubs
must be searched for by digging up the ground. In
early spring the grubs are frequently numerous in
meadows.

SquasH BuGs can usually be found wherever squash
vines grow. In August or September is the best time
to look for them.

GIANT WATER BUGS are most easily collected from
under electric lights. They may be drawn from shal-
low ponds with a minnow seine, and a very similar
bug, though smaller, Zaitha fluminea, is found abun-
dantly in similar places.

TD. INTRODUCTION TO ZOOLOGY.

Dragon Friigs of the larger kind are hard to cap-
ture in quantities. Smaller species of Agrion may be
used instead of the larger Libellulide. The larvee may
be dragged from a pond with a minnow seine or a dip
net.

It is very advantageous to have a wire net for dip-
ping specimens from the water. A hemispherical fly
screen, such as is sometimes used for covering table
dishes is very convenient for this purpose, when
soldered to the wire hoop of an insect net.

BUMBLEBEES are easily captured in a clover field.
They are most abundant in early fall. They are most
easily captured in an insect net, although on a cool
morning a net is superfluous.

Every farm boy knows how to jug bumblebees.
When a nest is found, a jug containing a small quan-
tity of water is unstopped and set near the opening of
the nest. The nest is then stirred up lively with a
pole, and the operator retires with celerity to a safe
distance. The bumblebees that come out of the nest,
finding no one to attack, will begin to settle down, but
instead of returning to the nest, most of them will go
by pairs into the jug.

Hornets may be captured by closing the aperture
of the nest and injecting chloroform until all commo-
tion ceases.

Mud nests should be procured whenever they are
finished. If necessary, wasps may be collected from
the flowers.

HovusE FLIES may be most easily secured from a
wire trap.

SPIDERS may be captured with the hands. There
is no danger from a spider bite, and spiders very
seldom bite. The brilliant Argiope riparia is
frequently found in great numbers along hedges or
on low bushes where cattle and other stock are not
allowed to run.

COLLECTING AND PRESERVING MATERIAL. 173

CENTIPEDES may be found by turning over flat
stones or logs, or pulling loose the bark from dead and
decaying stumps and trees.

CRAWFISH may be captured with a minnow seine,
or caught with bait. A piece of liver as large as a
man’s fist is tied to a string and thrown into the
stream. Crawfish cluster over it and cling to it, even
when drawn above the water. A net or dredge gently
slipped under the combination of liver and crawfish
will prevent the escape of many. Crawfish should be
boiled before being put into strong alcohol.

Sow sues are to be looked for under boards or
other articles that lie on the ground. They are found
only in damp places.

TADPOLES are collected from ponds in early spring.
It is well to collect a supply of toad eggs, frog eggs,
young tadpoles that show the gills, larger tadpoles for
dissection, and tadpoles that show the legs in various
stages of development. If some frog eggs or toad eggs
are discovered that are freshly laid, or better, if a
female is confined in a jar at the time when the eggs
are deposited, the different stages in the egg develop-
ment may be obtained. Two-celled, four-celled, eight-
celled, sixteen-celled, and thirty-two-celled stages are
all easily recognized with a simple lens.

Toad eggs and all other soft material are best pre-
served in formalin. This can be obtained from drug
stores for about sixty cents a pound. Four per cent of
formalin has been found a very satisfactory strength
for laboratory use. Dilute one pound of formalin
with about twenty-four pounds of water. Put it into
fruit jars and drop frog eggs, tadpoles, and such ma-
terial intoit. This makes.an effective preservative for
less than twenty-five cents a gallon.

Frogs and toads are preserved also in formalin.

FisH may be captured in the fishing season and
preserved in the same way, but if the school is near a

i174 INTRODUCTION TO ZOOLOGY.

market, it will be found better to purchase them fresh
when they are needed.

For the proper preservation of vertebrate material
while it is being studied, two plans may be used.
Usually it will be found advantageous to study verte-
brates in the winter, that being the most convenient
time for procuring and preserving the material.
A large ice box will be found very convenient to
keep the specimens in from day to day. If the
weather is warm, the ice box may have ice to keep
the specimens cool. If the weather is very cold,
the ice box may serve to keep the specimens from
being frozen too hard, while still cold enough to be
preserved.

A more satisfactory way, however, is to preserve
the vertebrate specimens in one per cent formalin.
Each day at the close of the study period the speci-
mens are put into a large receptacle, like a wash
boiler, galvanized iron bucket, or any other article
of that nature. The next day they must be taken out
and distributed, work being resumed where it had
been left off.

Specimens preserved in this way will need to be
tagged. Small strips of zinc written on with a lead
pencil and tied to the specimen with a pining have
proved very satisfactory.

The principal objection to such use of formalin is
that it bleaches out the blood vessels, making them
difficult to trace; but it rather improves the muscles
and nervous system.

For the satisfactory handling of vertebrate mate-
rial, some large iron pans like baking bans (which
can be procured very cheap) will be found convenient.

Eartuworms should be procured fresh if possible ;
but they may be preserved in formalin.

CLAMS AND OysTERS can be bought in the market ;
but if available markets are not near, fresh-water

COLLECTING AND PRESERVING MATERIAL. 175

clams, snails, and slugs should be collected and pre-
served in four per cent formalin. A supply of shells
should be kept for the purpose of identifying the
principal parts before beginning to study the struc-
ture of the body.

STARFISH must be procured from the seashore.
They are usually preserved in formalin, and will
keep indefinitely. The usual cost is about two dol-
lars per dozen.

FRESH-WATER SPONGES must be collected late in
the fall; September and October are the best months.
Until this season, the gemmules are not matured and
the growth has not reached its maximum. For most
purposes it is sufficient to dry them and then preserve
them from the dust in boxes. To study the flesh and
cellular structure, they should be preserved in forma-
lin or very strong alcohol. Absolute alcohol is the
best preservative of sponges when careful dissection
is intended. Sponges should be dropped into abso-
lute alcohol as soon as collected.

Hypras, DAPHNIA, CYPRIS, CYCLOPS, VORTICELLA,
PARAMECIUM, STENTOR, AND AM@BA would better be
obtained in a fresh condition. This means that, as a
general thing, these animals would better be studied
in the spring or in the fall, Aquaria once stocked
with them and kept in the schoolroom will usually
furnish a fairly good supply of one or all of these
forms. A jar, with a handful of hay put into it and
let stand from year to year, will usually show
several forms of protozoa, including vorticella and
paramecium.

It is better to keep all aquaria covered. - This
prevents the growth of a screen of bacteria which is
destructive to most other life in the aquaria. If this
be done, the water will not need any changing.

Pupils should be encouraged to collect their own
material and material for the class whenever possible.

176 INTRODUCTION TO ZOOLOGY.

There is nothing like making the acquaintance of an
animal at home; but the wise teacher will always
have a supply of material on hand from which
he may draw when the exigencies of the occasion
demand it.

Alcohol for laboratory use may be obtained from
any distillery in half-barrel or barrel quantities with-
out paying the internal revenue tax. Permission
must be obtained from the government through the
internal revenue collector for the district, and a bond
for double the amount of the tax must be filed with
him to insure the legitimate use of the alcohol.

Each pupil should be provided with a lens, a pair
of forceps, a pair of scissors, and a sharp knife or
scalpel. These can be obtained for about one dollar.
It is most profitable for the school to furnish these
instruments.

Each pupil should also have a dissecting dish, an
alcohol cup, a pair of dissecting needles, a towel, and
a piece of soap. A candy tray which can be bought
for ten cents makes a very good dissecting dish. A
small museum jar with a tight fitting lid makes a
good alcohol cup, but a wide mouthed bottle with a
tight cork may be substituted. A screw capped oint-
ment bottle does very well. The dissecting needles
may be made by thrusting the eye end of a sewing
needle into the end of a pine stick, whittled into
the shape of a lead pencil. A notebook in which
the pupil records his observations and drawings is
indispensable.

A small collection of illustrative material will be
found of great help. A collection of insects, showing
the most common forms in the immediate vicinity,
will be useful and capable of arousing great interest.
The insects should be killed in a cyanide bottle,
pinned with insect pins, and preserved in an insect
case. A cigar box with a layer of sheet cork tacked

COLLECTING AND PRESERVING MATERIAL. 177

in the bottom serves very well for some purposes.
Spool cases, which can be obtained for a small amount
of money, are more convenient. These should be
prepared by lining the bottoms of the drawers with
sheet cork and covering the surface of the cork with
white paper ruled into squares. The squares aid very
much in the arrangement of the different species.
The entire drawer should be covered with a pane of
glass supported by a small piece of wood at each cor-
ner. A lump of camphor kept in each drawer will
effectually protect its contents from destruction by
moths and dermestes. A better method, though more
expensive, is to buy Comstock boxes and use the block
system of keeping collections.

The wings of butterflies should be spread on a set-
ting board. This is made by nailing two smooth pine
boards, $ of an inch thick and two feet long, about
# of an inch apart. The space between them is
covered by sheets of cork. This forms a grooved
board with the bottom of the groove lined with cork.
The butterfly is pinned through the thorax with an
insect pin. This pin is stuck into the cork at the bot-
tom of the groove. The wings are drawn out at the
sides so that the hind edges of the fore wings form
a straight line across the board. Strips of paper are
then pinned to the board across the wings to fasten
them in position until they become dry.

Individual specimens of spiders, myriapods, and
insect larvae may be kept in homeopathic vials, pre-
served in strong alcohol.

Snail shells are best preserved in small boxes, or in
homeopathic vials if the shells are very small.

Much advantage will be derived from a series of
mounted slides of parts of insects such as are figured
in this book. If one knows exactly what to look for,
a good deal of the structure can be made out with the
hand lens. Such slides are easily prepared. Put the

178 INTRODUCTION TO ZOOLOGY.

object (for example, the tongue of a fly) into strong
alcohol. This should be either absolute (one hundred
per cent is always preferred) or ninety-eight per
cent, or even ninety-five per cent. It should then
be placed on a glass slip 1x3 inches and covered
with clove oil. In afew minutes the excess of clove
oil should be removed with a blotter, and the object
covered with a drop of Canada balsam made liquid
with xylol. A cover glass is then placed on the slide,
with the object in the center, and pressed down with
a clamp like a spring clothes pin. In a few days the
balsam near the edges will be dry, and any excess
may be scraped off with a knife. The principal dif-
ficulties will be to use alcohol strong enough to
remove all the water, and ¢o avoid the inclusion of a
bubble of air in the balsam.

If only one compound microscope can be had, it may
be made very serviceable to a whole class by means
of a porte lumiere. This is easily and cheaply
made as follows: Set a board twenty inches wide
across a window, under the sash. Cut a hole four
inches in diameter near one edge of this, and in this
hole mount a double convex lens having a focus of
about twelve inches. The lens is the condenser.
Directly under the lens, near the bottom of the board,
cut a slit large enough to allow another board six
inches wide and # inch thick to pass. Let this
transverse board extend about a foot outside the room.
Fasten it firmly. On the outer end of the board,
mount a mirror 9x12 inches in such a manner that it
can be turned in two directions. Small iron rods
running from the mirror frame to the inside of the
window board may be used to turn and hold it.

The mirror is used to reflect sunlight upon the
condenser. This concentrates the rays of light toa
point at the focus, To take out the rays of heat, a
tank composed of two plates of glass separated at the

HOMEMADE PORTE LUMIERE. 179

ends and bottom by a thick rubber tube and clamped
together, is filled with a saturated solution of alum
and set in front of the condenser.

A microscope is set on the transverse board so that
the front of the object glass shall be at or near the
focus of the condenser. An object is placed upon the
stage, the mirror of the microscope is turned out of

HOMEMADE PORTE LUMIERE.
(Arranged for projecting microscopic objects.)
the way, the tube is placed horizontally, and the
image is projected upon a wall or screen and focused
by the microscope adjustment. The room of course
must be darkened. Screens made of carpet paper or
black calico are very effective; but if regular opaque
shades mounted on rollers can be procured, of course
they are to be preferred. With this instrument, a
microscopic object is seen by a whole class at once in
its natural colors. Moving objects, such as_proto-

180 INTRODUCTION TO ZOOLOGY.

plasm, crustaceans, vinegar worms, blood corpuscles
in the tail of a minnow or in the web of a frog’s
foot, are shown as easily as with a mounted slide.
Small glass tanks, made by cementing rubber ends
and bottom to two glass slips for sides, are useful for
showing living animalcules.

A picture of such an apparatus, which cost, all
told, $1.50, exclusive of the microscope, is here given.
It has been found very effective and useful.

MICROGRAPHIC CAMERA,
(Arranged for showing a microscopic object to several persons at once.)

Another device for showing an object to a class is
easily available, and a picture “of this also is given.
This device,called a micrographic camera, was designed
and used for photographing from a microscope, but
it was found to be very useful also for showing an ob-
ject to half a dozen persons at once, and has been
used for that purpose.

MICROGRAPHIC CAMERA. 181

A starch box, by means of a piece fastened to its
side, is clamped to an upright piece supported on a
base. The top of the starch box holds a piece of
ground glass in aframe. In the bottom of the box is
a hole large enough to receive the tube of a microscope.

To use the apparatus, an object is placed on the
stage, the mirror reflects sunlight up the tube, the im-
age appears on the ground glass, and is focused by the
microscope adjustment. Half a dozen pupils can see
the object at once if a large cloth be thrown over the
heads of the whole group, thus excluding much of the
light. :

CHAPTER XII.

CLASSIFICATION OF ANIMALS.

The classification of animals is in a very unsatis-
factory condition. There is no general agreement
among naturalists concerning it. The following ar-
rangement of the principal groups of animals will
serve as a kind of background, or map of the animal
Kingdom, in which the student may locate the ani-
mals he has studied and see the extent of untraveled
territory.

BRANCH I. PROTOZOA. Single-celled animals.

CLASS 1. Rhizopoda.—Amceba.
2. Sporozoa.—All parasitic.
3. Flagellata.—Each animal is provided with a
' flagellum, or large vibrating hair.
4. Infusoria.—Vorticella, Paramcecium, etc.

BRANCH II. PORIFERA. Sponges.

CLASS 1. Calcarea.—Spicules calcareous.
2. Cornacuspongia.—Fresh-water and commercial
sponges.
8. Spiculispongia.—Uniaxial or tetra-axial siliceous
sponges.
4. Hyalospongia—Six-rayed siliceous spicules.

BRANCH III. C@LENTERATA. Animals with a per-
manent body cavity.
CLASS 1. Hydromedusce.—Hy dra.
2. Scyphomedusee.—Jelly fishes.
3. Anthozoa.—Corals.
4. Ctenophora. Ctenophores.
182

CLASSIFICATION OF ANIMALS. 183

BRANCH IV. HLCHINODERMATA. Rough skinned
animals.

CLASS 1. Crinoidea.—Crinoids, mostly extinct.
Asteroidea.—Starfish.
Echinoidea.—Sea urchin.
Holothuroidea.—Sea cucumber.

BRANCH V. VERMES. Worms.
CLASS 1. Platyhelminthes.—Flat worms.

irae 09

2. Nematelminthes.—Thread worms.
3. Rotatoria.—Rotifers.
4. Polyzoa.
5. Brachiopoda.—Have shells, like a clam.
6. Tunicata.
7. Nemertina.
8. Enteropneusta.
9. Gephyrea.
10. Annulata.—Earthworm, leech.

BRANCH VI. MOLLUSCA.

CLASS 1. Lamellibranchiata.—Clam, oyster.
2. Gasteropoda.—Snail.
3. Cephalopoda.—Squid.

BRANCH VII. ARTHROPODA. Jointed appendages.

CLASS 1. Crustacea.

ORDER 1. Cirripedia.—Barnacles.

2. Entomostraca.—Cyclops, etc.
3. Tetradecapoda.—Sow bug, etc.
4. Decapoda.—Crawfish.

CLASS 2. Myriapoda.

ORDER 1. Chilognatha.—Have two pairs of legs to
each segment.

2. Chilopoda.—Centipede.

CLASS 3. Arachnida.

ORDER 1. Acarina.—Ticks and mites.

2. Pedipalpi.—Daddy longlegs.
3. Araneina.—Spiders.
CLASS 4. Insecta.

ORDER 1. Neuroptera.—Dragon fly.
Orthoptera.—Grasshopper.
Hemiptera.—Squash bug.
Coleoptera.—Beetle.
Diptera.—House fly.
Lepidoptera.—Butterfly.
Hymenoptera.—Bumble bee.

SEO tS

184 INTRODUCTION TO ZOOLOGY.

BRANCH VIIL VERTEBRATA.

CLASS 1. Pisces.
ORDER 1. Leptocardii.cAmphioxus.
2. Marsipobranchii.—Lamprey.
3. Elasmobranchit.—Sharks and 1ays.
4. Ganoidei.—Garpike.
5. Teleostei.—Nearly all common fishes.
CLASS 2. Batrachia. ;
ORDER 1. Proteida.—Persistent gills. Proteus.
2. Urodela:—Salamander.
3. Anura.—Frog and toad.
CLASS 3. Reptilia.
ORDER 1. Ophidia.—Snakes.
2. Lacertilia,—Lizards.
3. Chelonia.—Turtles.
4. Crocodilia.—Alligator.
CLASS 4. Aves.
ORDER 1. Cursores.—Ostrich.
2. Steganopodes.—Cormorant, pelican.
3. Pygopodes.—Loon.
4. Longipennes.—Gulls.
5. Tubinares.—Petrel.
6. Anseres.—Geese and ducks.
7. Herodiones.—Herons.
8. Paludicole.—Marsh birds. Crane.
9. Limicole.—Shore birds. Snipe.
10. Raptores.—Hawks and owls.
11. Psittaci.—Parrots.
12. Gallince.—Chickens and turkeys.
13. Columbee.—Pigeons.
14. Coecyges.—Cuckoos.
15. Picit.—Woodpeckers.
16. Machrochires.-Humming birds.
17. Passeres.—Sparrows, etc.
CLASS 5. Mammalia.

ORDER 1. Monotremata.—Ornithorhynchus.
Marsupialia,—Opossum.
Edentata.—Sloth.
Rodentia.—Rabbit.
Insectivora.—Hedgehog, mole.
Cheiroptera.—Bat.
Cetacea.—Whales and dolphins.
Sirenia.—Manatee.
Proboscidea.—Elephant.
Ungulata.—Horse, cow.
Carnivora.—Cat, dog.
Primates.—Monkeys, man.

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CHAPTER XIII.

ANALYTICAL TABLES,

FOR DETERMINING THE FAMILIES OF INSECTS.

How to Use the Tables.

The purpose of the following tables is to enable a
student to find the family to which an insect belongs.
Their principal value is to direct the attention of the
student to the morphological differences that separate
families from each other. Morphological differences
are not of the greatest importance, and in some
instances may seem very trivial, but they enable us
to designate, easily and clearly, families that differ
widely from each other in habits, life history, and
economic importance. The study of type forms of
animals is not sufficient in itself to give us any idea
of the wealth of animal life that exists around us.
Particularly is this true of insects, with their 250,000
species already described. A very little time devoted
to the determination of insect families will add largely
to our appreciation of their importance.

Although tables for six orders are given, it is not
expected that one class will try to master all of them.
It is better for one class or one student to confine
himself to the insects of one order until a satisfactory
familiarity with the insects of that order has been
acquired.

In many instances it will be found very difficult

185

186 INTRODUCTION TO ZOOLOGY.

to render a proper decision where an alternative is
offered. There are two reasons for this: First, the
student may not know the meaning of the terms
employed, or have a satisfactory image of the things
they represent. A study of the glossaries and the
structure of the insect will help to overcome this diffi-
culty. Second, the distinguishing mark is often one
of comparison, expressed by longer, shorter, thicker,
slender, somewhat, etc. This can be aided only by
comparison of many insects, and will be overcome by
experience.

Every teacher and every student ought to know
how to use a set of analytical tables. That in itself
is a valuable acquisition. Let us study how to use
these. Weshould always make a careful examination
of the specimen in hand before turning to the tables.
Suppose each student has a beetle in hand. The
first division of the Coleoptera is marked—

A—Head not distinctly prolonged into a beak.

It is or it is not prolonged. If it is prolonged, we
omit all divisions under A— and go to AA—; but if it
is not prolonged, we read the next division,—

B—Hind tarsi with the same"number of joints as the others.
The hind tarsus either has or has not the same num-
ber as the others, so we say ‘‘Yes’’ or ‘‘ No,’’ accord-
ing as it agrees or disagrees with the characterization
in B—. If we decide ‘‘ No,’’ we turn at once to—

BB—Front and middle tarsi 5-jointed; hind tarsi 4-jointed.
If our previous decision was right, it must fit here.
Then we read—
C—Anterior coxal cavities closed behind.
They are either closed or open. If open, we omit
all intervening divisions and go at once to—

CC—Anterior coxal cavities open behind.

ANALYTICAL TABLES. 187

Next we go to the first division under CC—, which is—
D—Head not suddenly and strongly constricted at the base.

We must determine first what is meant by suddenly
and strongly constricted at the base, and here some
known examples will help us greatly. Suppose we
decide that the head is suddenly and strongly con-
stricted. Wesay ‘‘No,’’ to D—and proceed to DD—.
The first division under DD— is—

E—Lateral sutures of the thorax distinct; base as wide as the elytra.
If we say ‘‘No’’ to this, we go to—

EE—Lateral sutures of the thorax wanting.
The first division under this is—

F—Tarsi perfect, with distinct claws; eyes normal; prothorax at the
base narrower than the elytra.

An examination of F—, FF—, and FF F— shows that
the narrow prothorax distinguishes F— from FF—,
and the eyes normal, with distinct claws, distinguishes
F— from FFF—. Suppose we say ‘‘ Yes’’ to this
character, we go to—

G—Hind coxee not prominent.

If we decide that the hind cox are prominent, we go
to GG—, the first division of which is—

H—Claws simple; head horizontal.

If we say ‘‘No’”’ to this, we go to—

HH—Claws cleft or toothed; front of head vertical,—

and at the end of this line we find, in parenthesis, the
name of the family, Meloide, which is the family of
blister beetles, all of which have a very curious life
history.

Half a dozen beetles traced through in this way
will give us a very fair understanding of the tables.

The names of ‘the families all end in —idz, and the
accent falls on the syllable just before this termination.

188 INTRODUCTION TO ZOOLOGY.

Table for Determining the Orders of Insects.

A- Mouth parts fitted for biting.
B—Yore and hind wings of dilferent textures. : f
C—Fore wings hard and horny, not useful for flying; hind wings mem-
branous, naked, folding longitudinally and Pee Beetles.
(Coleoptera.)
CC—Iore wings leathery, sometimes wanting; hind wings membranous,
folding longitudinally; direct metamorphosis..... _+++-(Orthoptera.)
BB—Fore and hind wings similar in texture, but seldom folding. (Neuroptera.)
AA—Mouth parts fitted for sucking, lapping, or piercing. :
B—Wings only two, hind wings rudimentary.........-..6. sees e eee (Diptera. )
BB—Wings four.
C—Wings clear with few veins; biting mandibles present. (Hymenoptera.)
CC—Wings scaly; mouth parts a long, coiled sucking tube. (Lepidoptera. )
CCC-—Wings either membranous, or front pair horny at the base; mouth
WATH @ JOINTEM DEKE: ies ieioieis saiesie.sie doe! sie'bibr0 wis nie bin-8ie 0/8 carey (Hemiptera. )

Table for Determining the Families of Orthoptera.

A—Hind legs enlarged and fitted for leaping.
B—Antennee much shorter than the body; ovipositor short; auditory organ
OD: ther AbA omen www wis Sohecwn wy bis Gesa.ch. Maha 3.9) sates . ..(Acrididee.)
BB—Antennz much longer than the body; auditory organ on the fore legs.
C—Tarsi composed of three segments; abdomen with long, hairy anal sty-

lets; color generally brown or black. Crickets .............. (Gryllidee.)
CC—Tarsi composed of four segments; anal stylets short; ovipositor flat or
sword-shaped; color generally green. Katydids......... (Locustidee.)

AA—Hind legs not fitted for leaping; tarsi of five segments.
B—Fore legs enlarged and fitted for grasping; head transverse, wider than
the thorax; thorax greatly elongated.... 0... .... seen ae eee ee (Mantide.)
BB—Legs all nearly alike and fitted for walking; head exposed and not
especially wider than the thorax; body greatly elongated. Walking

STICK Shee Guin, (hae aes Aine, nt chen thss hada > sides cee abenrie Wr tyaaE ae. Teme Phasmide.)
BBB—Legs alike and used for locomotion; head concealed beneath the shield-
shaped prothorax; body flattened. Cockroaches........... (Blattidee.)

Table for Determining the Families of Hemiptera.

(Arranged by permission from Comstock’s Entomology.)

A—Beak jointed; with or without wings.
B—First pair of wings thickened at the base, thinner at the tip.
C—Antenne shorter than the head, and nearly or quite concealed in a cavity
beneath the eyes.
D—Hind tarsi without claws.
E—Fore tarsi_flattened, with a fringe of hairs on the edge, and without

claws. Head overlapping the prothorax................. (Corisidee. )
EE—Fore tarsi of the usual form, and with two claws; head inserted in
the: protheran: <siciscecs scmampean, eases sremiestamaca sh apache (Notonectide.)

DD—Hind tarsi with two claws.
E—Caudal end of the abdomen furnished with a respiratory tube com-

posed of a pair of grooved thread-like orgams........... - (Nepidee.)
EE—Abdomen without respiratory tube.
F—Legs flattened for swimming................ es ose (Belostomide.)
IF'F—Legs titted for walking.
GW INOW O CON sosiaisis 45 s.5ie as da tea dco giecd Male wlerbidonsecn

AcE egos (gaigntiae?

+G—Ocelli present. .. .. weaetee. (Galgulidae,

CC—Antennee at least as long as the head; usually free.
D—Body linear; head as long as the three thoracic segments.
(Limnobatide.)
DD—Body of various forms, but when linear, with the head shorter than
the thorax.
E—Last segment of the tarsi more or less split, and with the claws
inserted before the apex.
F¥'—Boidy usually elongated; prothorax narrow; beak 4-jointed; second
and third pairs of legs extremely long and slender. (Hydrobatidx.)

ANALYTICAL TAs, 189

FI'—Body stout, oval, and broadest across the prothorax; beak 3-
jointed; legs not extremely long........ 0... 2.0... (Veliide. )
EE—Last segment of the tarsi entire, and the claws inserted at the apex.
F'—Antenne 4-jointed.
G—Wing covers resembling net work; not much distinction between
corium and membrane ............ Savaiald aa uit cextaays Hert (Tingitide.)
GG—Wing covers not as above.
H—Beak 3-jointed.
I—Wing covers, when well developed, with a cuneus; when not
well developed, no ocelli.... 220. ....-. 2... 0-000- (Acanthiidee. )
II—Wing covers, when well developed, without a cuneus; when
not well developed, ocelli present.

J—Ocelli wanting.
K—Body linear. 0.0.0... cess cee sea veeeescee sees (Amesidea.)
KK—Body greatly flattened... ae » ....(Aradidee.)
KKK —Body ordinary .....-... 00.0... .002.0-+ 2. (Reduviide. )

JJ—Ocelli present.
Ix—Beak very long, reaching to or beyond the intermediate

COMES 6 r aacarsade ensieuessigeushial tod dle snip ogra a tegns vs En fboie wanes (Saldide.)
KK—Beak not reaching intermediate coxe.

L—Femora of front legs greatly thickéned... (Phymatide.)
LL—Front femora little thickened, less than half as wide

ASO reesei ain arch areiees iv aeons ahiardeg shai (Reduviidee.)
HH—Beak 4-jointed.
I—Front legs fitted for grasping prey.............0. 0005 (Nabide.)

Ii—Front legs fitted for walking.
J—Wing covers with cuneus, almost without veins. (Capside.)
JJ—Wing covers without cuneus, membrane with four or five
veins.
Fe Ocelli Wanting s..scccseieee cd Sota oeneen (Pyrrhocoride.)
KK—Ocelli usually present.
L—Head with a transverse incision in front of the ocelli
(Bery tide.)
LL—Head without transverse incision.
M—Membrane with four or five simple veins arising from

the base of the membrane ............... (Lygeide. )
MM—Membrane with many usually forked veins arising
from the transverse basal vein.......... (Coreid.)

FF—Antenne 5-jointed.
G—Scutellum nearly flat, narrowed behind.
H—Tibie unarmed, or furnished with very short spines.
(Pentatomidee.)

HH—Tibiz armed with strong spines. .... .............(Cydnide.)
oes ee very convex, covering nearly the whole of the ab-

omen.
H—Lateral margins of the scutellum with a furrow in which the
edge of the Wing cover fits when closed ... ... (Corimelanide. )

HH—Lateral margins of the scutellum without a furrow.
(Scutelleridae. )
BB—Wings of the same thickness throughout.
C—Beak evidently arising from the head; tarsi 3-jointed; antenne minute,
bristle-like.
D—Three ocelli, males musical; wings entirely membranous; large insects.

(Cicadidee.)
DD—Ocelli two or wanting; males not musical.
E—Antennee inserted on the sides of the cheek beneath the eyes.
7 (Fulgoride.)
EE—Antenne inserted in front of and between the eyes.
‘—Prothorax not prolonged above the abdomen. i
G—Hind tibie with one or two stout teeth, and the tip crowned with
SHOPE/SLOUE SPINES sseicec wounds eievaln ce eradewiete Setiocpernce (Cercopide. )
GG—Hind tibie having a row of spines below.......... (Jassidee. )
FF—Prothorax prolonged into a horn or point above the abdomen.
(Membracidee.)
CC—Beak apparently arising from between the front legs, or absent; tarsi
one or two-jointed; antennee, usually prominent and thread-like,
sometimes wanting.
D—Tarsi usuaily two-jointed; wings when present four in number.

190 INTRODUCTION TO ZOOLOGY.

I— Wings transparent.
F—Hiud legs titted for leaping; antenne nine- or ten-jointed.
(Psyllidee. )
FF—Legs long and slender, not fitted for leaping; antenne three- to

SOVEN-JOUMCOG sso occ te-ceasuraraye-ste piotareeasinieyt ok wth AN wees te (Aphididee.)

EE—Wings opaque, whitish; wings and body covered with a whivish

POW GER. «tse sinks Set os. eM ee ae cease dadoaeae naa (Aleyrodide. )

DD—Tarsi one-jointed; adult male without any beak and with only two
wings; female wingless. Scale insects............+...-2-+ (Coccide. )
AA—Wingless; fleshy, unjointed beak. Lice......... cs... eee e ee (Pediculide. }

Glossary for the Table of Hemiptera.

Caudal—towards the tail, or posterior part.
Corium—the thickened basal portion of the fore wings.
Cuneus—a triangular portion of the terminal part of the corium marked off
from the rest by a line.
Membrane—the thin posterior portion of the fore wings.
Scutellum—the triangular piece on the back between the bases of the fore
wings.

Table for Determining the Families of Neuroptera.

(Odonata, Ephemerida, Corrodentia, Plecoptera, Isoptera, Mecoptera, Neu-
roptera, Trichoptera, Mallophaga.)
A—Wingless, or with rudimentary wings.
B—mouth parts fitted for biting.
C—Head with a long trunk-like beak. ... 2.0.6... ce. ceeeee eres (Panorpide.)
CC—Head not prolonged into a trunk.
D—Louse-like insects.
E—Antenne not more than five segments. Bird lice.. Dunia ores )

EE—Antenne with many segments. Book lice... .. - (Psocidee. )
DD—Not louse-like; abdomen sessile; legs not fitted for. jumping: body
white and somewhat ant-like in form..........-.-..056. (Termitide. )

AA—Winged.
B—With two membranous wings; abdomen with caudal filaments; mouth
parts rudimentary; halteres wanting.................. .. (Ephemeride.)

BB—With two pairs of wings. Wings similar, membranous.
C—Wings net-veined, with many veins and cross veins.
D—Tarsi consisting of less than five segments.
E—Antennie inconspicuous, awl shaped, short, and slender.
F—First and second pair of wings nearly the same length; tarsi three-
i Ointed: DPAgON THIS cp. cance sued ona peoens (Libellulidee. )
FF—Second pair of wings either small or wanting; tarsi four-jointed.
(Ephemeride.)
EE—Antenne usually conspicuous, not awl shaped and'slender.
F—Tarsi two- or three-jointed.

G—Second pair of wings the smaller ................0..00005 (Psocide. )
GG—Second pair of wings broader, or at least of the same size as the
ATSC Dail soy ee ys 3) Neos ss os lak Gee Ha htanmaeh Tae a ee (Perlide.)

FF—Tarsi four-jointed, wings equal
DD—Tarsi consisting of five segments.
E—Abdomen with setiform, many-jointed anal filaments.
(Ephemeride.)

ceeds eBioias aikiae mandate (Termitide.)

EE—Abdomen without many-jointed anal filaments.
F—Head prolonged into a trunk-like beak ...... 0. ...... (Panorpide.)
FF—Head not prolonged into a beak.
G—Prothorax as long as or longer than the meso- and meta-thorax
combined.

H—Fore legs greatly enlarged and fitted for grasping.
(Mantispide.)
HH—Fore legs not enlarged and not fitted for grasping.
(Raphidiide. )
Be Epon not so long as the meso- and meta-thorax com-

ine

ANALYTICAL TABLES. 191

H~—Hind wings broad at the base, and the part nearest the body
folded like a fan when not in use ............ -.. 006 (Sialidee.)
HH—Hind wings narrow at the base and not folded.
I—Antenne knobbed, or enlarged, toward the end.
(Myrmeleonide.)
II—Antenne without terminal enlargement.
J—Some of the transverse veins between the costa and subcosta
forked; wings brownish or smoky .. .....(Hermerobiidz.)
JJ—Transverse veins between the costa and subcosta simple;
WINES: CTCONISN ce 4.635 sacaiejaig Seis Be? we wraceia's, Rajan (Chrysopide. )
CC—Wings with branching veins and comparatively few cross veins or
veinless.
D—Tarsi two- or three-jointed.
E—Posterior wings smaller than the anterior .. ...... ..... (Psocide.)
EE—Posterior wings as large as or larger than the anterior ones.
(Perlide.)
DD—Tarsi four- or five-jointed.
E—Abdomen with setiform, many-jointed anal filaments. (Ephemeride.)
EE—Abdomen without many-jointed anal filaments. Second wings as
large as or larger than the first. Moth-likeinsects. (Phryganeida.)

Although in the above table all the families in-
cluded have been grouped into one order of Neurop-
tera, the differences existing among them are so very
great that they are more properly separated into sev-
eral orders. The following table will indicate the
orders to which the several families belong.

ORDERS. FAMILIES.
Odonata .......Libellulide.—Dragon flies
Plecoptera ..... Perlidze.—Stone flies
Isoptera....... . Termitidee.—White ants
Corrodentia ....Psocidze.—Book lice
Mallophaga ....Mallophagide.—Bird lice
Mecoptera ..... Panorpidz.—Scorpion flies
Trichoptera ....Phryganeidae.—Caddice flies, or Caddice worms

Sialidee.—Horned corydalis
Raphidiide.—Found only in the far west
Mantispide.—Somewhat like praying mantis
Chrysopidze.—Lace-winged flies
Hemerobiide.

Myrmeleonidee.—Ant lions

Neuroptera. .

Table for Determining the Families of Diptera.

(Arranged by permission from Williston’s North American Diptera.)

A—Head separated from the thorax by a neck; never parasitic.
B—Antenneze many-jointed, often longer than the thorax.
C—Dorsum of the thorax with a complete V-shaped suture....... (Tipulidee. )

192 INTRODUCTION TO ZOOLOGY.

CC—Dorsum of the thorax without a V-shaped suture.
D_A complete CISC al CELL PrESOMG sed sates -ecede cepa ace tes teen ain (Rhyphide.)
DD—No discal cell.
E—Antenne composed of three joints, with a terminal arista.
(Orphnephilid. )
EE—Antenne apparently not composed of three joints and a terminal
arista.
F—Wings with only a few longitudinal veins and no cross veins.
(Cecidomyide.)
FF—Wings usually many-veined.
G—Ocelli present.
H—Wings broad, bare, marked by numerous folds between the
veins, giving a ne.ied, spider web-like appearance.
(Liponeuride.)
HH—Wings not so marked.
I—Coxee much elongated........ 0... cee e eee eee de a ci
LN CORES SOUT... Gesvatassye sisi sid sessacecesntessiecaild siavaue ave soa aiec Ma atwaace (Bibionide.
GG—Ocelli wanting.
H—Costal or marginal vein not extending beyond the tip of the
wing.

I—Antenne slender, the joints more or less constriéted, and often
bushy plumose; legs slender, hind tibie and metatarsi never
dilated; abdomen slender; wings narrow....(Chironomide. )

II—Antenne shorter than the’ thorax; never hairy; legs strong,

hind pair dilated; body thick- “set; wings broad.
(Simuliide.)
HH—Marginal vein encompassing the whole wing.
I—Wings ovate, with ten longitudinal veins and no cross veins.
(Psychodide.)
II— Wings with cross vein near the middle.
J—Wings hairy, fringed on the margin. Mosquitoes.
(Culicidee.)
JJ tae bare, the second vein arises near the middle of the
AUT Bess Sea nada he enka esaperee, lateyadate™ anaydle: ene logztals daigicG' aia senuaags (Dixide.)
BB—Third joint of aie complex; basal cells of the wing long.
C—Empodia developed pulvilliform.
D—Alule rather large; third longitudinal vein forked. Horseflies.
(Tabanidee.)
DD—Alula small or rudimentary. Mostly flower flies.
E—Tibie wholly without spurs; costal vein not reaching beyond the tip

of the win: ‘ . (Stratiomyidee. )
EE—Middle tibia, at ‘Teast, ‘With’ spurs; costal vein ‘encompassing the
MWIDLOLS WAI By rasicaeg aoreiseay stata toucestone Sistas ans, axerale gterbigietoagi ade eearnag rane saie (Leptidie. )

BBB--Antenneze composed of three simple joints”
C—Anutenne apparently composed of a single joint with a long bristle; femora
flattened, hind legs long. Small, quick-running, hump-backed ‘fies.

(Phoridee.)
CC—Not such flies.
D--Empodia developed pulvilliform; that is, three nearly equal membra-
nous appendages on the under side of the claws.
FO ALUN eG VCE: LAP GCs sca ai ssreieyeocss tdioie 80 wenrse.“pibioin inte sd wzsbuistsindgieteisns sia.e (Acroceridee. )
EE—Alule of moderate size or rudimentary.

F—Middle tibie, at least, with spurs; no bristles on femora or tibie;
third longitudinal vein forked; five posterior cells present; an-
terior cross vein always distinct; third joint of the antenns with_
a bristle, or slender style, usually COMMU AL isis ee srcsnssione (Leptide. )

FI—Not such flies.

G—Third longitudinal vein forked, two or more submarginal cells
present.
H—Arista, or style of antenne, always present and dorsal.
I—Head comparatively small; proboscis more or less elongated.
(Empidee. }
II—Head as broad as the thorax; proboscis fleshy. .(Platypezidee.
HH—Arista terminal or absent.
I—Vertex and front distinctly hollowed out between the eyes.
Mostly large flies.
J—Proboscis with fleshy labelle at the tip; palpi rudimentary
or wanting....... b cyasue: xb aceiers Sealdienaieiseinscsiatierers cetana) miele (Mydaidee.)

ANALYTICAL TABLES. 193

JJ—Proboscis without fleshy labellas at the tip; palpi usually
f 9) 05.000 959 0 Cen eer eres ere a een etn er ere (Asilide. )
II—Vertex and front plane or c ex.

J—Never more than four posterior cells in the wing.

K—Third antennal joint without bristle, or style; fourth longi-

tudinal vein terminating at or before the tip of the wing.

f F (Scenopide. )

KK—Third antennal joint usually with terminal style; fourth

longitudinal vein terminates beyond the tip of the

wing.
L—Anal cell narrowly open or closed near the margin; dis-

CALCELMLESEN Gs s.sis: caters wemcicancsen sinter cawisters (Bombylidz. )
LL—Anal cell closed remote from the border, or the discal
COW AS WANtiNe osc. ctsios ve neonnawanen aemneses (Empide. )

WING OF HORSE FLY (TABANUS.)

1.—Discal cell. a.—Costal vein.
2.—Second basal cell. b.— Auxiliary vein.
3.—First basal cell. ¢e.—First longitudinal vein.
4.—Costal cell. d.—Second mS -
5.—Anal cell. e.—Third ee ue
6.—Auxiliary cell. f.—Anterior branch of third vein.
8.—Marginal cell. g.—Fourth longitudinal.
9.—First submarginal cell. h.—Fifth es
10.—Second ‘ ay = i—Anterior cross vein.
11.—First posterior cell. j.—Anterior intercalary vein.
12.—Second = k.—Posterior interealary vein.
13.—Third oe “ 1.—Posterior cross vein.
14.—Fourth NE es
15. - Fifth se e

JJ—Five posterior cells in the wing.
K—Neuration intricate; anterior cross vein wanting or rudi-

mentary....... phan eek rt id Sap oo . (Nemistrinide. )
KK—Neuration not intricate; anterior cross vein always dis-
tinct.

L—Fourth vein terminates beyond the tip of the wing.
(Therevide. )
LL—Fourth vein terminates before the tip of the wing.
(Apioceride.)
GG—Third longitudinal vein not forked.
H—Antenna With a terminal arista, or styte.
I—Wings pointed, no cross veins in the middle. . (Lonchopteride. )
JI—Wings rounded, not lancet-like.

194 INTRODUCTION TO ZOOLOGY.

J—Second basal cell confluent with the discal cell, not separated
Yb? VOID. = svete esi are de sted. seen os Seah seers (Dolichopodidee.)
JJ—Second basal cell separated from the discal cell by a vein,
K—Antenna with a terminal bristle.
L—Head comparatively small; proboscis more or less elon-
gated; alules of the wings usually rudimentary.

(Empide.)

LL—Head broad as the thorax; Proboscis fleshy; aluls

GISHiNGh. icedaeies. Co Luis mew oaintee (Platypezide.)
KK—Antenna with a terminal style.

L—First posterior cell open ...... (Empide.)

M-—Face convex transversely or with a median ridge,
never with a subantennal depression.
N—A spurious longitudinal vein, between the third and
fourth longitudinal veins, crossing the anterior
CLOSS VOU is sages oF. eo 4-s .. (Syrphide.)
NN—Spurious vein never present (Pipunculide.)
MM—Face with subantenna. ooves or depressions.
N—Proboscis horny and elongate, often folding back
near the middle; abdomen never with bristles.
(Conopide.)
NN—Proboscis fleshy and not elongate; if elongate and
slender, the body with distinct bristles, or the
bristle of the antenna plumose. ...... (Muscide.)
HH—Antenna with a dorsal arista.
I—Proboscis rudimentary; palpi wanting. Bot flies. (Oestride.)
II—Proboscis not rudimentary; palpi present.
J—Second basal cell confluent with the discal cell. Small, bril-

liant colored, predaceous flies ... .......(Dolichopodide.)

JJ—Second basal cell separated from the discal cell by a small
cross vein.

K—Basal cell of the wing elongate, anal cell closed toward the
margin.

L—Face convex transversely or with a median ridge, never
with a subantennal groove or depression.

M—A spurious longitudinal vein, between the third and
fourth longitudinal veins, crossing the auterior
GCROSSAVCIMG « scisieie as sis wee Wedicsenaend apcre ah cce ence ON (Syrphidee.)

MM-—Spurious vein never present.......... (Pipunculide.)

LL—Face with subantennal vertical grooves or depressions.

M—Proboscis horny and elongate; abdomen never with
Bristlesi.c. s.ccon es, senanu os da eee, Semin (Conopidee )

MM--Proboscis fleshy and not elongate; if elongate and

slender, the body with distinct bristles, or the
bristle of the antenna plumose .... .... (Muscid.)
KK—Posterior basal cell small; anal cell always closed _re-
mote from the margin.........(Conopidee or Muscide.)
AA—Parasitic flies.

B=-PAaPasitic Ory Dats ia cise ayes speid.ase $.8,ace eicreie aacestvareis ee \atein Siniciavecas eles (Nycteribide.)
BB—Parasitic on birds or mammals .............cceeceeeeeeees (Hippoboscide.)

Note.—The family of Muscide includes nearly one-third of all the flies. By
some dipterologists it is divided into about twenty-one groups which may be
called families.

‘

Glossary for the Table of Diptera.

Dorsum—the dorsal or upper side of the body.

Discal cell—see figure of the wings.

Alule—the backward, membranous extension of the wings.

Pulvilins—one of the two pad-like, fleshy cushions between the claws.

Empodium—the middle appendage of the foot between the claws. Some-
times pad-like, sometimes bristle like, sometimes wanting.

Metatarsus—the first Jone of the tarsus; usually larger than the other
segments.

Plumose—turnished with long, soft, feather-like hairs.

Arista—a bristle, or strong hair, growing on the antenna.

ANALYTICAL TABLES. 195

Table for Determining the Families of Coleoptera.

(Adapted from LeConte and Horn’s Classification of the Coleoptera of North
America.)

A—Head not distinctly prolonged into a beak.
B—Hind tarsi with the same number of joints as the others.
C—Fourth and tifth tarsal joints not connate.
D—First ventral segment divided by the hind coxal cavities, so that the
sides are separated by the very small medial part.

E—Metasternum with an antecoxal piece, separated by a well marked
suture, reaching from one side to the other, and extending in a tri-
angular process between the hind coxee.

F—Antenne 11-jointed; habits terrestrial.

G—Antenne arising at the side of the head between the base of the
mandibles and the CYeS,........... cece eee ee eee eee (Carabidee. )
GG—Antenne inserted on the front above the base of the mandibles.
(Cincindelide )
FF—Antenne 10-jointed; habits aquatic; hind coxe fixed and with

large plates almost entirely concealing the abdomen.
(Haliplidee.)
EE—Metasternum without antecoxal piece, prolonged into a triangular

process posteriorly; habits aquatic.

F—Antenne slender, filiform or setaceous; abdomen with six seg-

MENUS CYS LWO sc isicncuaisens coat Loran Hanes cates (Dy tiscidee.)

IFrF—Antenne irregular, very short; abdomen with seven segments;

CV CS LOULS Sse Noctis ot Ns cs i aediae Mark Pialdes steeda Sats TANONS (Gyrinide. )

DD—First ventral segment visible for its entire breadth.

E—Antenne clavate or capitate, not lamellate............ (Clavicornide )

#-Horsal segments of the abdomen entirely corneous; elytra usually
short.

G—Abdomen flexile, ventral segments eight ..... ...(Staphylinide )

GG—Abdomen not flexile, segments five or six.......... (Pselaphide.)
FF—Dorsal segments of the abdomen partly membranous; elytra
usually long. .

G—Tarsi five-jointed, at least on one pair of tarsi.
H—Mentum large, quadrate; palpi distant at the base; habits
usually aquatic. Rae noe rar (Hydrophilidee. )
eo Mee moderate or small; labial palpi approximate at the

ase.
I—Ventral segments 1-3 connate.

J—Fifth joint of tarsi longer than the others combined; claws

Wear Be? gccanet | y wuanciiatethans vetceuntoie un medabanlrinkte tian 0esecd (Parnide.)
- JJ—Fifth joint of tarsi not longer than others combined; claws
MUSED 9 wi ang ara caaiapesiuaiwnn als avsrauarsios “opginte agave niratalevere (Rhyssodide.)

Ii—Ventral segments free.
J—Anterior coxe large, conical, prominent.

K—Posterior coxee more or less conical and prominent.
L—Eyes finely granulated, sometimes absent..... (Silphidee.)
LL—Eyes coarsely granulated... .......... (Scydmzenidee. )

KK—Posterior cox not prominent.

L—Antennez moderate in length, capitate; posterior cox

sulcate for the thighs; body usually scaly or pubescent.

(Dermestide. )

LL—Antenne long, slender, sometimes capillary; last ven-

tral segment elongate; tarsi long and slender.

(Scaphidiidee. )

JJ—Anterior coxz conical, transverse, slightly proniinent;

prothorax strongly toothed on the sides. ...(Derodontide.)
JJJ—Anterior cox not prominent.

K—Anterior coxee rounded or oval.

L—Posterior coxe not sulcate for the reception of the

thighs.
M—Posterior coxe contiguous.. ......... ...(Phalacride. )
MM—Posterior cox separated. ‘
N—First ventral segment more elongated...... (Ptinide.)

NN—Ventral segments sub-equal. ia
O—Middle coxal cavities open externally ...(Cucujidee.)

196 INTRODUCTION TO ZOOLOGY.

OO—Middle coxal cavities closed by the sterna.
P—Prosternum not prolonged behind
(Mycetophagidw. )
PP—Prosternum prolonged behind, meeting the
mesosternum.
Q—Anterior coxal cavities open behind.
(Oey propa see: )
QQ—Anterior coxal cavities closed behind
(Erotylidee, )
LL—Posterior cox sulcate to receive the thighs
(Throscide.)

KK—Anterior coxe transverse.
L—Posterior cox flat, not sulcate to receive the thighs.
M—Antenne straight.
N—Tarsi more or less dilated, first joint not short.
(Nitidulidee.)
NN-Tarsi slender, first joint short. ... .. (Trogositide. )
MM—Antenne geniculate; tibize usually all dilated.
(Histeride. )
LL—Posterior coxze grooved for the zaepmen of the thighs;
body oval, convex, legs retractile.. ..(Byrrhide.)
GG —Tarsi four-jointed.
H—Wings fringed with hairs; very small species..... (Corylophide.)
HH—Wings not fringed with hairs.
I—Ventral segments 1-4 connate.
J—Antenne regular; legs not fossorial............. (Colydiidee. )
JJ-Antenne short, irregular; legs fossorial....(Heteroceride.)
Il—Ventral segments free.

J— Anterior coxvw trANSVELSE 2... ... cece eee cee ees (Nitidulide. )
JJ—Anterior coxe globose.
K—Tarsi slender. . . .-.(Endomychide. )

KK—Tarsi more or less dilated and spongy beneath.
(Erotylide.)
JJJ--Anterior coxx oval.

K—Form depressed; head, free. ........... (Mycetophagide.)
KK—Body cylindrical, thorax prolonged over the wae ‘a
(Ciide.)

GGG—Tarsi 3-jointed,
H—Wings fringed with long hairs; abdomen with 6 or 7 ventral
segments; antenne slender, verticillate, minute species.
(Trichopterygidv.)
HH—Wings not fringed.
1—Tarsi with the second joint dilated.
J—Claws abpendiculatels or toothed; first ventral segment with
coxal lines........ (Coccinellidee. )
JJ—Claws simple ; first ventral segment ‘without coxal lines.
(Endomychide. )
IIl—Tarsi with second joint not dilated.
J—Elytra entire; ventral Seu Tmen Us nearly equal. (Lathridiide.)
JJ—Elytra truncate; ventral segments 1 and 5 longer.
(Trogositide.)
KiE—Antenne serrate.
IF'—First and second qoultay ‘Segmentsuc connate; st with membra-
nous lobes. .... Si .. (Buprestidae. )
FF—Ventral segments free.
GS TUTS 1s AI OIE vas tercsaseh ivaiteasiavetcanaies “aatesaasesaainersieteateraereiatereisiee (Ciidee.)
GG—Tarsi 5- -jointed.
H—First ventral segment elongated; antenne terminated by a
CWORJOINCOULCHUD ws sia are secaace: Acne Saini REAR TERI (Ptinide.)
HH—First ventral segment not elongated,
I—Hind coxe sulcate to receive the thighs.
J—Front cox globose.
K—Prothorax loosely articulated; prosternum prolonged be-
hind; front coxal cavities entirely prosternal.
e (Elateride. )
KK—Prothorax firmly articulated; front coxal cavities
closed behind by mesosternum ; antenne sometimes
with a 3-jointed club... 6.6.0... cece eee ee (Throscidie. )

ANALYTICAL TABLES. 197

JJ—Front coxee transverse.
K—Onychium small, or wanting.
L—Head not constricted behind; eyes granulated. Meso-
thoracic epimera reaching the coxe..... (Dascy]llidee. )
LL—Head not constricted behind; eyes granulate; Meso-
thoracic epimera not reaching the coxse. (Ptinide.)
LLL—Head constricted behind; eyes smooth. (Cupesid.)
KK—Onychium large and hairy.......... .....- (Rhipiceride.)
II—Hind coxee flat, not sulcate.
J—Prosternum not prolonged behind; tarsi with membranous
ODES 2 csp. ssetccessstienscossicionsyapsne sseeuiaces toi asioasncasisaauascrsiosiaceeetene (Cleride.)
JJ—Prosternum prolonged behind. ........... .... (Throscide.)
III—Hind coxe prominent, not sulcate.
J—Front coxe large, globose, without trochantin. (Ptinide.)
JJ—Front cox long, with distinct trochantin.

p

VENTRAL SIDE OF HARPALUS CALIGINOSUS.

1.—Prosternum. 7.—Metasternal episternum. 13.—Mentum.
2.—Prosternal episternum. 8.—Antecoxal piece. 14.—Mandible.
3.—Coxal_ cavities, closed _9.—Trochanters. 15.—Antenna.
behind. 10.—Femora. 16.—Ligula.
4.—Mesosternum. 11.—Posterior Coxe. 17.—Paraglossie.

5.—Mesosternalepisternum. 12.—Gula, with the gular 18,.—Labial palpus.
6.—Metasternum. sutures. 19.—Maxilla,

198 INTRODUCTION TO ZOOLOGY.

K—Ventral segments 7 or 8........ ceeseeeee «+ (Lampyride.)

KK—Ventral segments 5 OF 6. we eee cee eee ee (Malachiide.)
EEE—Antenne with a lamellate club; legs fossorial.

F—Lamelle of club not capable of close apposition, and usually not

flattened. 60... . cect eee cee cee eee nt ate renee ees (Lucanide. )
FF—Lamelle of club of antennw capable of close apposition, and
MALTON =: -oerecmenmiaans |, aia mige ... (Scarabeidie.)

¢C—Fourth and fifth tarsal j S grown together, the fourth very small,
hence apparently 4-jointed; Antennze filiform, rarely serrate, or
feebly thickened externally.
D—Tarsi dilated and spongy beneath.

E—Antenne usually long or greatly developed, frequently inserted on
frontal prominences; front often vertical, large and quadrate;
pronotum rarely margined; tibial spurs distinct. (Cerambycide.)

EE—Antenne moderate or short, not inserted on frontal prominences;

front small, oblique, sometimes inflexed; pronotum most fre-
quently margined; tibial spurs usually wanting.
(Chrysomelidee.)
EEE—Front prolonged into a broad, square beak; antennee inserted in
front of the eyes, variable in length serrate or pectinate.
(Bruchide.)
DD—Tarsi not dilated; sensitive surface in deep impressions. (Spondylide.)
BB—Front and middle tarsi 5-jointed; hind tarsi 4-jointed.
C—Anterior coxal cavities closed behind.
D—Tarsal clavs simple.

E-Penultimate joint of the tarsi not spongy. ........... (Tenebrionida)
EE—Penultimate joint of the tarsi spongy beneath. (Lagriide.)
DD—Tarsal Claws Pectinate...... 0... cccsecceeessae 26 veneeenses (Cistelidee. )

CC—Anterior coxal cavities open behind.
D—Head not suddenly and strongly constricted at the base.
E—Middle cox not very prominent.
F—Thorax margined at the sides (Melandryidz.)
FF—Thorax not margined e . (Pythidee.)
EE—Middle coxe very prominent.......... 0.6... cee ee eee (Hidemeride. )
DD—Head suddenly and strongly constricted at the base.
E—Lateral sutures of the thorax distinct; base as wide as the elytra.
F—Hind coxe laminiform ‘ ds ..(Mordellideae.)
(Melandryidee. )

FF—Hind coxe not laminiform.... ... ....
EE—Lateral sutures of the thorax wanting.
F--Tarsi perfect, with distinct claws; eyes normal; prothorax at the
base narrower than the elytra. .........2. cesses eee (Anthicide.)
G—Hind coxe not prominent.
GG—Hind coxe large, prominent.
H—Claws simple; head horizontal .................65 (Pyrochroide.)
HH—Claws cleft or toothed; front of head vertical...... . (Meloide.)
FF—Tarsi with distinct claws; eyes normal; prothorax at the base as
WAC OVAS GMOIOLY GIB as/tescrast/.scransivicpersnisn icicjatesie rete (Rhipiphoride.)
FFF—Tarsi without claws; eyes pedunculated............ (Stylopide.)
AA--Head more or less prolonged into a beak; palpi rigid and labrum wanting
(except in Anthribide); gular sutures entirely confluent along median
line; prosternal sutures wanting.
B--Antenn straight, filiform...... . (Brenthidee.)
BB—Antenne clavate, often geniculate.
C—Elytra without any fold, or with a very feeble one on the inner surface
near the edge; male and female pygidinm alike.
D—Labrum wanting; mandible flat, toothed on the inner and outer sides.
Rhynchitide. )
DD—Labrum wanting; mandibles stout, pincer-shaped. .....(Attelabidee.)
CC—Elytra with a strong fold on the inner surface.
D—Pygidium of the male divided.
E—Tarsi setose, or spinose beneath, narrow ..........6..065 (Byrsopide.)
EE—Tarsi usually dilated, brush-like beneath.
F—Mandibles with a deciduous piece, which is lost soon after comin
out of the pupa state, and leaves a svar .......... (Otiorhynchidee.
FF—Mandibles without an accessory piece .........-... (Curculionidee.)
DD—Pygidium of both sexes undivided.
E—Pygidium surrounded at the edge by theelytra; tibiee usually serrata.
(Scoly tidve.)

ANALYTICAL TABLES. 199

EE—Pygidium normal, covered or uncovered; tibie not serrate.
F—Antenne geniculate; labrum wanting. ........-...... (Calandride.)
FF—Antenne straight, 10- or 11-jointed; labrum distinct.

(Anthribide.)

Glossary for the Table of Coleoptera.

Ante-coxal piece—a piece of the sternum just in front of the coxa.

Apposition—position of being placed together.

‘apitate—knobbed, or enlarged at the tip; said of the antenne.
Clavate—terminal joints gradually increasing in size; said of the antenne.
Connate—grown together so as to be immovable upon each other.
Constricted—narrowed very suddenly.

Contiquous—close together, so as to touch.

Coxal cavity—the cepressian in the sternal plate into which the coxa is

inserted.

Byes pedunculated—eyes set in short stalk, or peduncle.

Filiform—threat-like; said of the antenne.,

Fossorial—Fitted for digging.

Geniculate—elbowed; the second joint so attached that it makes an angle
with the first, the succeeding joints continuing in line with
the second.

Glo»ose—round, somewhat like a ball, or globe.

Gula—the under side of the head, just behind the mentum. It constitutes

the principal part of the under surface of the head.

Gular sutures—the lines in which the two halves of the gula are joined

together or to a middle piece.

Lamelle—thin, flat plates.

Laminiform—having the form of thin flat plates.

Lamellate—terminal joints flattened so as to present flat surfaces to each

other; said of the antenne.

Mentum—that part of the under side of the head which lies immediately

behind the mouth.

Metasternum—sternum of the metathorax.

Onychium—a small appendage between the claws.

Pectinate—toothed like a comb; said of the antenne.

Penultimate—next to the last.

Pronotum—dorsal side of the prothorax.

Pubescent—covered with fine hairs.

Pygidium—the last dorsal segment of the abdomen.

Setaceous—hair-like; said of the antenne.

Serrate—toothed like a saw.

Setose—furnished with many hairs.

Spinose—furnished with many spines.

Sterna—plural of sternum; under side of the thorax and abdomen.

Sulcate—grooved.

Suture—a line in which one piece joins another.

Thorax margined—furnished with a thin edge, or shelf, projecting from the

thorax outward.

Trochantin—an accessory piece attached to the outer side of the middle

and anterior coxe.

Table for Determining the Families of Hymenoptera.

(Arranged by permission from Cresson’s Synopsis of the Hymenoptera of North
America. )

A—Posterior trochanters one-jointed.
B—Anterior wings with at least one closed complete sub-marginal cell.
C—Posterior tarsi with the basal joint more or less compressed and dilated,
and densely pubescent beneath.
D—Labium slender, not flattened, longer than the mentum; basal joints
of the labial palpi elongate............. 0. cece eeee eee aeceeeeee (Apidee. )
DD—Labium flattened, shorter than the mentum; basal joints of the labial
palpi not unlike the following joints. ................65 (Andrenide.)
CC—Posterior tarsi with the basal joint more or less cylindrical, never much
widened or densely pubescent.
D—Petiole of the abdomen simple, without scales or nodes.

200 INTRODUCTION TO ZOOLOGY.

E—Wings more or less folded longitudinally in repose; antenne filiform
or sub-filiform.

¥F--Intermediate tibiwe with two apical spurs.......-......... (Vespide.)

FF—Intermediate tibiz with one apical spur.............. (Eumenide.)

EE—Wings not folded longitudinally.

F—Prothorax usually consisting of little more than a narrow collar,
the posterior angles not reaching the tegule: female never wing-
less.

G—Anterior wings with two complete sub-marginal cells.
H—Prothorax short, transverse; metathorax short, rounded pos-
teriorly; clypeus not carinate or rostriform.
(Pemphredonide. )
HH—Prothorax long and narrow, produced anteriorly into a neck ;
metathorax elongate, truncate behind; clypeus carinate and
TOSULIPOLIM ys asictenesiaieers ot eisibisies Gate iets Aes vatieiels (Ampulicidee. )
GG—Anterior wings with three complete submarginal cells.
H—Abdomen sessile or sub-sessile.
I—Second submarginal cell receiving both recurrent nervures.
J—Marginal cell not appendiculate; mandibles with exterior
margin entire.
K—Labrum distinctly exserted, sometimes rostriform.
(Bembecide. )

KK—Labrum short, not exserted.... .... ....++ . (Nyssonidee.

Ne na VF

ANTERIOR WING OF HYMENOPTER (MELLINUS).

1.—Costal cell. a.—Costal nervure.

2.—Median cell, ,

3.—Sub median cell.
4.—Anal cell.

5.—Marginal cell.

6.—First submarginal cell.

7.—Second submarginal cell.

8.—Third submarginal cell.

9.—Fourth submarginal cell.

10.—First discoidal cell.
11.- Second discoidal cell.
12.—Third discoidal cell.
13.—First apical cell.
14.—Second apical cell.

b.—Sub costal nervure.
e.—Externo-medial nervure.
a.—Anal nervure.
— Marginal or radial nervure.
f.—Basal nervure.
g.—First transverso- cubital neryure.
h.—Second :
i.—Third ae cane fe
j.—Transverso-medial nervure.
k.—Discoidal nervure.
1.—Cubital nervure.
m.—First recurrent nervure.
n.—Second i
o.—Subdiscoidal nervure.
p.-—Stigma.
q.—Posterior margin.
r.—Apical margin.

JJ—Marginal cell appendiculate; mandibles deeply emarginate
on the exterior maryin ....00 0 we... .. (Larride. )
II— pies ong third submar, ginal cell each ree eiving a recurrent
oli datilsn oa. MyStelavcs Saja Viale a sto NesTIR alc onE ea (Philanthide.)
He Apaomen qpeviolate.

ANALYTICAL TABLES. 201

I—F¥irst submarginal cell not receiving a recurrent nervure.
J—Petiole of the abdomen depressed and generally furrowed
above; flagellum thickened at the apex; intermediate
tibize with one apical spur... ....... .++..-. (Mimesidee.)
JJ—Petiole of the abdomen cylindrical, smooth; flagellum
slender at the apex: intermediate tibise with two apical
SPULES o/scicseisisie aeisies deve’ ciaisietsr sjaimagne: yard veer ererereseigie' bre crae SS PMCCIGEEs)
II—First submarginal cell receiving a recurrent nervure,
7 (Mellinide.)
GGG—Anterior wings with only one complete submarginal cell.
(Crabronide.)
F¥F—Prothorax considerably produced posteriorly, the hinder angles
reaching the tegule; female sometimes wingless.
G—Abdomen with the first ventral segment not separated from the
second by a furrow or constriction of the joint.
H—Posterior legs long, reaching beyond apex of the abdomen;
eyes not emarginate within .............. ......(Pompilide.)
HH—Posterior legs short, not reaching to the tip of the abdomen;
eyes emarginate Within ........00 0 www. eeeeee (Sapygide.)
GG—Abdomen with the first ventral segment distinctly separated
from the second by a constriction or furrow.
H—Intermediate tibixe with one apical spur; female wirged.
(Scoliide.)
HH—Intermediate tibie with two apical spurs; female wingless.
(Mutillidee)
DD—Petiole of the abdomen with one or more scales or nodes; three sexes,
or kinds of individuals.
E—Petiole composed of a single joint.
F—Abdomen proper not constricted between segments one and
two.
(Formicide.)
FF—Abdomen proper constricted between segments one and two.
eae
EE—Petiole composed of two joints .........-.. sss sree cee (Myrmicide.
BB—Anterior wings without complete or closed submarginal cells.
C—Abdomen sessile, a little longer than the head and thorax, composed
apparently of only 3 to 5 segments, the remainder modified into a slen-
der, retractile, telescopic apparatus, generally not exserted; antennz
elbowed, short; body adorned with metallic colors, and often coarsely
and deeply sculptured ........ ... Slee) ahem, aor arr (Chrysididee. )
cC—Abdomen petiolate, of the female very long, at least 5 times as long as
the head and thorax; antenne long, thread-like, not elbowed; body
black, smooth and polished..... ........ 062.6 cece cece eee (Pelecinide,)
AA—Posterior trochanters two jointed.
L—Abdomen sessile or petiolate, united to the thorax by a portion only of its
transverse diameter, the articulation movable.
C—Anterior wings almost Veinless, without closed or perfect cells.
D—Posterior margin of prothorax reaching the tegule; ovipositor arising

from the apex of the abdomen . ..............--.06+ (Proctotrupide.)
DD—Posterior margin of the prothorax not reaching the tegule; oviposi-
tor arising before the apex of the abdomen...... ....(Chalcidide. )

CC—Anterior wings with several closed or nearly closed marginal or sub-
marginal cells. _
D—Anterior wings with a costal nervure and a more or less developed

stigma.

E—Abdomen attached to the extremity of the metathorax.
F—Anterior wings with but one recurrent nervure ...... (Braconide.)
FF—Anterior wings with two recurrent nervures ....(Ichneumonidz.)
EE—Abdomen inserted upon the dorsum or near the base of the meta-
CHOVAS cee | Gatcetaie ina tomer alge ae, dbeay ie aN saateeterad (Evaniide.)
DD—Anterior wings without a costal nervure or stigma; abdomen gen-
erally ovate, and more or less compressed .........-..+ (Cynipidee. )

BB—Abdomen connate, united with the thorax by the entire diameter of the

basal part, the articulation not movable,
C—Anterior tibize with one apical spur; abdomen of the female furnished at
the tip With @ DOrer........- cee. eevee eee eee ee ~~ --.-. ..(Uroceride.)
CC—Anterior tibise with two apical spurs; abdomen of the female furnished
at the tip With a pair Of SAWS .....-6e eee e eee seen eree ee (Tenthredinidee.)

202 INTRODUCTION TO ZOOLOGY.

Glossary for the Table of Hymenoptera.

Apical situated at or near the apex.
Appendiculate—said of a cell that has an incomplete vein extending from
one of its corners.
Cell—a space in the wing bounded by veins. For the names of the different
cells, see the figures of wings.
Carinate—furnished with a ridge.
Clypeus—that part of the upper or front side of the head which lies just be-
hind the labrum.

Emarginate—notched.

Exserted—projecting out.

Flagellum—the terminal portion of the antenna, usually consisting of ten

to twelve segments.'
Filiform—thread-like; slender.
Mentum—that part of the under side of the head which lies immediately be-
hind the labium.

Petiole—the slender rod which connects the abdomen and the thorax, as
seen on a wasp.

Pubescent covered with tine hairs.

Recurrent Nervures—see figures of wings.

Rostriform—shaped like a beak. ,

Sessile—without a petiole.

Tegula—a small plate or scale overlapping the base of the fore wing.

Truncate—cut squarely off.

INDEX.

Absolute alcohol, 175, 178.

Acephala, 138.

Acridide, 26.

Age of fishes, 102; of reptiles,
102; of invertebrates, 102.

Agricultural ant, 53.

Agrionide, 47, 172.

Air bladder, 88.

Air sacs, 115.

Air tubes, 20.

Alcohol, 176.

Alternation of generations, 156.

Ameeba, 168, 175.

Amphioxus, 132.

Analytical tables for determining
the families of insects, 185-202.

Anosia plexippus, 36, 171.

Ant, agricultural, 53.

Ant, leaf-cutting, 53.

Ants, 53.

Aquaria, 175.

Arachnida, 62.

Araneina, 62.

Archeopteryx, 119.

Argiope riparia, 172.

Arthromeres, 152.

Arthropoda, 18-78, 164.

Articulates, 164.

Astacus, 74.

Authority, 26,

Bacteria, 175.
Basilarchia archippus, 36.

Batrachians, 100.

Beavers, 130.

Beeswax, 59.

Beetle, 37, 171.

Bell animalcule, 160.

Belostoma americanum, 39.

Bénacus griseus, 39.

Bilateral symmetry, 152.

Birds, 104, 118.

Bivalves, 138.

Blattide, 31.

Blood corpuscles, 95.

Bollworm, 37.

Bombycide, 36.

Bombyx mori, 36.

Bot flies, 45.

Brachiopods, 149.

Branches of Animal Kingdom,’77,
167, 182.

Breathing, of grasshopper, 23; of
fish, 86; of frog, 94.

Budding, 156.

Bumblebee, 47.

Butterfly, 32, 171.

Calcareous shell, 120.
Cambarus, 74.
Carchesium, 161.
Carpet beetle, 38.
Caterpillar, 33, 171.
Cecropia moth, 35, 171.
Cell, 99, 158, 164, 166.
Centaur, 133.

203

204 INDEX.
Centipede, 63, 172. Cow flies, 45.
Checks on increase, 24, 181. Crab, 75.

Chilognatha, 65.

Chilopoda, 65.

Chinch bug, 41.

Chitin, 22.

Chlorophyl, 160.

Chrysalis, 33, 171.

Cicada, 39.

Circulation, of fish, 87; of frog,
94; of bird, 115.

Cladocera, 75.

Clam, 185, 174.

Classes of animals, 55, 182.

Click beetles, 38.

Clothes moth, 37.

Clover seed, 51.

Cochineal, 59.

Cockroach, 31.

Cocoon, 33, 171.

Codling moth, 37.

Coelenterata, 155, 164.

Collecting and preserving in-
sects, 59.

Collecting and preserving mate-
rial, 170.

Coleoptera, 37.

Comparison of tadpole and
fish, 98.

Comparison of pigeon and tur-
tle, 118.

Complete or indirect metamor-
phosis, 35.

Complex structure; 168

Compound eye, 19.

Comstock boxes, 177.

Comstock’s Entomology, 60.

Contractile vesicle, 161.

Copepoda, 75.

Corpuscles, 95.

Cotton worm, 387.

Crawfish, 68, 73, 173.

Crawling of earthworm, 146.
Cricket, 27, 170.

Crop of grasshopper, 19.

Cross fertilization of plants, 51.
Crustacea, 73.

Curculio, 38.

Cyanide bottle, 60.

Cyclops, 72, 175.

Cypris, 75, 175.

Daddy longlegs, 61.

Daphnia, 72, 175.

Definition, logical, 56, 78, 129, 168.

Dermestids, 38, 177.

Development, stages of, 34, 100.

Devil’s darning needle, 46.

Diapheromera femorata, 30.

Dipnoi, 86.

Diptera, 42, 45.

Directions to students, 9.

Direct or incomplete metamor-
phosis, 23.

Dragon fly, 46, 172.

Drawings, 10.

Drone bees, 50.

Dry fly, 40.

Ducks. 117.

Earthworm, 145, 174.
Echinoderms, 151.

Egg, 99, 110, 116, 165, 173.
Electric light bug, 39.
Elytra, 37.

Embryologic series, 101-103.
Endoskeleton, 89, 114.
Enemies of grasshopper, 24.
Entomology, 59.

Epistylis, 161.

INDEX.

Exoskeleton, 22, 114.
Eye, compound, 19.

Facets of compound eye, 19.
Feathers, 110.

Fish, 79, 178.

Fission, 165.

Fly, 42.

Food of grasshopper, 24.
Formalin, 178, 174, 175.
Formic acid, 50.
Fresh-water clam, 135, 175.
Fresh-water sponge, 157, 175.
Frog, 91, 178.

Fur beetles, 38.

Gall gnats, 45.

Ganoidei, 86.

Garpike, 85.

Gasteropods, 144.

Geese, 117

Gemmule, 157, 159.

Genera, 26.

Geologic series, 103.

Germinal disc, 116.

Giant water bug, 38, 171.

Gill breathing, 73.

Gill scoop, 74.

Gizzard of cricket, 28.

Gizzard of pigeon, 107.

Glossary, 190, 194, 199, 202.

Gnat, 45.

Gordius, 149.

Grasshopper, 138, 170.

Gryllide, 28; Gryllus abbrevi-
atus, 28; Gryllus luctuosus, 28.

Gypsy moth, 37, 181.

Habits of earthworm, 148.
Hair worm, 25.
Harpalus, 171.

205

Harvest fly, 40.

Heart, single, 87: respiratory, 87.
Hemiptera, 40.
Hermaphroditism, 147.
Hessian fly, 45.
Heterocercal tail, 86.
Heteromyenia argyrosperma, 159.
Heteroptera, 41.

Hind wing of wasp, 49.
Hinge ligament, 140.
Homocercal tail, 86.
Homology, 35, 66, 114.
Homoptera, 41.

Honey, 50.

Hoppers, tree, 41.

Hornet, 48, 172.

House fly, 42, 172.

Hydra, 155, 175.
Hydrachna belostome, 39.
Hydianth, 156.

Hydroids, 156.
Hymenoptera, 50.

Icerya purchasi, 132.

Imago, 34, 36.

Immortality of Protozoa, 165

Improper questions, 10.

Incisors, 180.

Incomplete or direct metamor-
phosis, 23.

Incubation, 116.

Indirect or complete metamor-
phosis, 35.

Individual, 156.

Injury done by grasshoppers, 24;
by moths, 37; by insects, 59;
by rabbits, 130.

Insecta, 13-60.

Insect net, 59.

Insects, orders of, 54, 183.

Instruments, 11, 176.

206

Jelly fishes, 155.
Jugging bumblebees, 172.

Katydid, 29, 170.
Keratin, 114.

Labelle, 43.

Lamellibranchiata, 138.

Larva, 34.

Leaf-cutting ant, 53.

Leech, 149.

Libellulide, 47, 172.

Lingual ribbon, 148.

Locomotion of fishes, 86; clam,
138; earthworm, 146.

Locustide, 29.

Logical definition, 56, 78, 129, 168.

Logical identity, 67.

Lung fishes, 86.

Madreporic body, 153.

Maggot, 45.

Mammals, 130.

Mantide, 31.

Mantis, 31.

Melanoplus differentialis, 170.

Melanoplus spretus, 24.

Metamorphosis, 28, 35.

Mice, 180.

Micrographic camera, 180.

Migration of birds, 117.

Mimicry, 36.

Minnow, 85.

Mollusks, 138, 149, 164.

Molting, 23.

Mosquito, 45.

Mosquito hawk, 46.

Moth, 34, 171.

Mounting microscopic objects,
177.

Muciparous glands, 89.

Mud nests, 52, 172,

INDEX.

Muscle fiber, 20.
Mussel, 152.

Myenia fluviatilis, 160.
Mylohyoid muscle, 95.
Myriapoda, 65.

Names; rules for, 26.

Nectar, 50.

Nematocysts, 156.

Neuroptera, 46.

Neuters, 50.

Nictitating membrane, 104, 134.
Notebook, 10, 176.

Notochord, 86, 132.

Nucleus, 87, 116.

Number of species of insects, 59.

Odonata, 47.

Odontophore, 144.

Ontogenetic series, 101-103.

Orders of insects, 54, 183; of rep-
tiles, 120, 184.

Orthoptera, 31.

Ostracoda, 75.

-Oyster, 140, 174.

Paramoecium, 162, 175.
Parasites, 25.
Parthenogenesis, 41.
Pedicellarize, 153.
Peristome, 160.
Phalangidea, 62.
Phasmide, 30.
Phylogenetic series, 103.
Pigeon, 104.

Pisces, 85.

Plant lice, 41, 58.
Poison of bee, 50; of spiders, 63.
Pollen, 50.

Pollen basket, 47.
Porifera, 157, 167, 182.

INDEX. 207
Porte lumiere, 178. Sharks, 85.
Praying mantis, 31. Shellac, 59.

Pressure upon subsistence, 132.
Proboscis of fly, 42.

Productions of insects, 59.
Proper questions, 10.

Protective coloration, 25, 29, 36.
Protective resemblance, 30.
Protoplasm, 163.

Protozoa, 102, 160, 165.
Punctorial bristle, 38.

Pupa, 34.

Queen bees, 50.

Rabbit, 121, 180.

Radiates, 152, 164.

Radula, 144.

Rats, 130.

Reproduction by fission (proto-
zoa), 165.

Reproduction of parts, 153, 156.

Reptiles, orders of, 120.

Review topics, 21, 56, 75, 89, 98,
111, 126, 153, 168.

Rodentia, 130.

Rudimentary organs, 36.

Rules for naming, 26.

Salamander, 100.

Samia cecropia, 36.

San Jose scale, 131.
Sauropsida, 119.

Scales from wing of butterfly, 35.
Scolopendra, 66.
Scolopocryptops, 65.
Segmentation of the egg, 116.
Selachii, 85.

Senses of insects, 24.

Setting board, 60, 177.
Seventeen year cicada, 40.

Silk, 36.

Silky locust mite, 24.
Skeleton, 22.

Slipper animalcule, 162.
Slug, 144, 175.

Snail, 142, 175.

Snake doctor, 46.

Social organization, 50
Solitary wasps, 52.

Sow bug, 71, 173.

Species, 26.

Species of insects—number of, 59.
Spicules, 158.

Spider, 61, 172.

Spider webs, 63.
Spinnerets, 63.

Spiracles, 15, 20, 28.
Sponge, 157.

Spongiolin, 157.

Squash bug, 39, 171.
Squirrels, 130.

Stages of development, 34, 100.
Starfish, 140, 150, 175.
Stentor, 162, 175.

Sting, 49.

Struggle for existence, 132.
Sturgeon, 85. ;
Survival of the fittest, 132.
Symphoricarpus, 62.
Synopsis of chapters, 7.

Tables for determining the fam-
ilies of insects, 185-202.

Table of addition of organs, 167.

Tables of differences, 30, 34, 55,
65, 77, 96, 98, 111, 128, 129, 141,
148, 150.

Tables of resemblances, 31, 55,
77, 118, 129, 141, 148, 164, 166.

208 INDEX.

Tachina flies, 25.

Tadpole, 97, 173.
Tapeworm, 131.
Taxonomic series, 102-103.
Teleostei, 85.
Temperature of birds, 115.
Tent caterpillar, 37.
Tetradecapoda, 75.
Thousand legs, 64.

Toad, 96, 173.

Tobacco moth, 37.
Tomato moth, 37.

Tongue of bee, 48; of wasp, 49.

Trachee, 20.
Tree hoppers, 41.
Trichina, 149.
Turtle, 117.

Univalves, 144.
Useful products of insects, 59.

Vermes, 148, 164.

Vermiform appendix, 134.
Vertebrates, 129, 164.
Vestigial organs, 36, 134.
Vinegar worm, 149.

Von Baer’s principle, 99.
Vorticella, 161, 175.

Walking stick, 30, 171.
Warning colors, 51.
Wasp, 48, 52.
Wasp nests, 52.
Wax, 50.

Webs, 68.

Wheel bug, 41.
Wiggler, 45.

Wire worms, 38.
Wood borers, 38.
Woodpeckers, 117.
Wolf-berry, 62.

Zaitha fluminea, 39, 171.
Zodlogic series, 102-103.

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