CORNELL UNIVERSITY LIBRARY FROM The Dent. of Zoology aor University Library QL 53.H iti of zoology. iil mann 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 AND 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, and 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 amethod 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 restof 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:.ceccee ee ceee seetee seen euneeeereneesereeere 9 CHAPTER I.—THE GRASSHOPPER ..... 10. cece cece cece renee eet et eee eeeeee 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. aie SA ath reteatere se teeanerae 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 IITI.— OTHER INSECTS..............055- Gignac Geayepnidosicsta Ae 308 Wnieeaien 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........0. 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,...... 0000 cc eect et cnee cee etter cence tte ee eee nee: 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 FIS.......... cee secretes ete e nee seen eens eeee nana cnes 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: VIT—BATRACHIA secscnermereueie we een chee eeoaan 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, circulation, 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. CHAPTER IX—MAMMAIS..... ... a SUI A asia ea cates eee iene eves oes S The rabbit—Laboratory directions—Table of differences between a fish, frog, pigeon, turtle, and rabbit—Table of resemblances—Definition of each class of vertebrates—Definition of vertebrate—Table of differ- 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 bene 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 iO G 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, orlower 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- rax, 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 thd’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 miin’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 cesophagus 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. 13. 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-cesophageal ganglion around the csophagus 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 ovw'eca tra’ehe ’vi duct in tés’tine w@ so phig’e al wri 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 striae, which are always consid- ered indicative of voluntary muscle. The Young Grasshopper. Ss I 1. Examine the young old one. sasshopper as you did the 2. Notice the body divisions, head, antenne, eyes, ocelli, labrum, mandibles, labium, labial palpi, max- ile, 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 SoURwror 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, antennee, 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. ‘ The grasshopper breathes through spiracles which open into the trachev, 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 larvee 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; b, 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 have 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 lve 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. é 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 CRICKRBT, 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 norso 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- . - Walking hopper. Cricket. Katydid. Stick. Acridide. | Gryllide, | Locustidiw. | Phasmide, Ear.... Locomotion 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 maxilla. 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. FAG OWE os Gh hers Ss cancse MRS S|" = SUITIVEIG, pezteroeds = a — Argeuuss 7 i = Leto} RTI wieysds sno -AIOU JOUTY a = = = -SIp ‘SuUeVZ.0 OATISOSIP eqyeredes = = = as cs Aqtaeo ~~ = =a - = Apoq Morpoy s3se Aq = = = = = = sonpordet {sTjeo AueuL = ae eu a = = SOTISTIOJOR e = = i a a = -IBYO [VUILU *BYVIG9II9 A “epodo1yjry *BOSNTTOTAL “*SOULIO A VIVULIOPOMIYOM] “VIVIEIUITHOH *R19TIIOF *R0Z0J01d “q1qqey ‘rad doyssery) “WRID “ULOMUIIET “YsyaRys “eIpsAH ‘asuodg “mmM1OD WRIeT SMOT[OJ SU ‘sTRUITU Jo SdNOIS YUOLEYIP It} OF SURSIO Jo TOTJIPPL OY} SULMOYS o[qeq B OXL IAL 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? ODMH TVR Oo 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 Fuiizs 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. Houser 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 i74 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 conyenient. 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. Thisis 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. Ina few 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 @ 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. Scyphomeduse.—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. Hiee 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. SE Oe 184 INTRODUCTION TO ZOOLOGY. BRANCH VII 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. Columbcee.—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. a SYeraapwe me or 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 FFF— 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 coxeze 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—YIore 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 eeee ee (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 WATE BW JOINTEM DEBE © i.e ieicieis saiesasersie doe! sunsbshr0 wie te bin-80e oh 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 whAOMen wwe wis Sohwown wy bis Gesa.h Maha so) 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. Kuatydids......... (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... ... sees ae eee (Mantide.) BB—Legs all nearly alike and fitted for walking; head exposed and not especially wider than the thorax; body greatly elongated. Walking STICK She Guin | hae aes Aine nt cheats, hadasy > siilges “ee mbenniewrteaaae Tee 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: