UNIVERSITY OF CALIFORNIA DEPARTMENT OF EDUCATION GIFT OF THE PUBLISHER No. <> , Received / LIBRARY OF THE UNIVERSITY OF CALIFORNIA. GIFT OF BtOLOSY LIBRARY G Class INTRODUCTION TO ZOOLOGY INTRODUCTION TO ZOOLOGY A GUIDE TO THE STUDY OF ANIMALS FOR THE USE OF SECONDARY SCHOOLS BY CHARLES BENEDICT DAVENPORT, PH.D. ^ ASSISTANT PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF CHICAGO DIRECTOR OF THE BIOLOGICAL LABORATORY OF THE BROOKLYN INSTITUTE OF ARTS AND SCIENCES, LOCATED AT COLD SPRING HARBOR, LONG ISLAND AND GERTRUDE CROTTY DAVENPORT, B.S. FORMERLY INSTRUCTOR IN ZOOLOGY AT THE UNIVERSITY OF KANSAS WITH THREE HUNDRED AND ELEVEN ILLUSTRATIONS THE MACMILLAN COMPANY LONDON: MACMILLAN & CO., LTD. 1900 All rights reserved COPYRIGHT, 1900, BY THE MACMILLAN COMPANY. J. S. Cashing & Co. — Berwick & Smith Norwood Mass. U.S.A. PREFACE THE general plan of this text-book is at the same time both old and new. Old, because it attempts to restore the old-time instruction in Natural History ; new, because " Natural History " is not to-day what it was a genera- tion ago. The treatment will seem new also in contrast with modern text-books of zoology, since they are devoted primarily to comparative anatomy, a field upon which we lay little stress. This departure is the outcome of a conviction that the needs of the secondary student are not best met by a course in comparative anatomy. That conviction is not altered by the circumstance that anatomy is fundamental for advanced work in zoology and physiology, for only a sixth of the secondary students go to college, arid proba- bly less than four per cent of them continue their zoologi- cal work there. The vast majority of secondary students, then, are not to be zoologists, but rather men of affairs. What the ordinary citizen needs is an acquaintance with the common animals that may be the companions of his country walks, and that may even stray into Wall Street, Dearborn Street, or Commonwealth Avenue. He wants to know where else over the world the common animals of his State are to be found and, as a legislator or as a taxpayer, he wants to know how animals affect man. It is more important for him to know these matters than to know the location of the pedal ganglion of the snail, or 231737 vi PREFACE to be able to recite the various ingenious hypotheses of the ancestry of echinoderms. Our conviction is, we feel sure, the common conviction of college teachers of zoology, who have often occasion to deplore the ignorance that their students show about common animals. It is the conviction of many other thoughtful men also who have recognized that an interest in nature is a powerful agent in making men morejnoral, more capable of appre- ciating the world they live in, and of finding satisfaction in living. The aim of the book is indicated by its title. It is not a treatise on the modern science of zoology. It is a guide to the study of animals, which it is hoped may introduce many students to the sciences of comparative anatomy, comparative embryology, cytology, general physiology, variation and inheritance, and the others that are grouped under "zoology." This book is like a u Synoptic Room " in the vestibule of a vast museum, containing the most essential things for those who can go in but a little way, but also fundamental for those who can penetrate farther. The illustrations of this book have received especial at- tention. An attempt has been made to give a lifelike figure of a representative of almost every family mentioned in the text. For courteous permission to reproduce the copied figures we are deeply indebted to many publishers and authors. We have to thank the authorities of the Field Columbian Museum for original photographs, Figs. 301, 302, and 305. Mr. H. W. Menke, of the same institution, kindly gave us permission to use his interesting photo- graphs of live rattlesnakes, Figs. 261, 262. To Mr. V. H. Lowe, Entomologist of the New York State Agricultural Station at Geneva, N.Y., we are indebted for the photo- PREFACE Vll graphs marked V. H. L.; these are published by permis- sion of the Director of the Station. The majority of the original photographs, designated by the initials W.H.C.P., were made by Mr. William H. C. Pynchon, Instructor in Biology at Trinity College, Hartford. All of these, ex- cepting Figs. 183, 184, 188, and 203, are photographs of animals occurring around the Biological Laboratory at Cold Spring Harbor, Long Island. They have thus a cer- tain scientific value as indicating the fauna of that region. As many of these figures are from living animals, probably never before photographed in their natural attitudes, their publication may be considered as something of a contribu- tion to science. Of the other photographs, Figs. 31 a, 122, 276, 281, and 288, marked D. and S., were contributed by Professor N. F. Davis of Bucknell University, Lewisburg, Penn., and Mr. Ernest A. Sterling of the same institu- tion; and Figs. 127, 251, and 259 were contributed by Mr. E. R. Downing, graduate student at the University of Chicago. The figures of birds by Louis Agassiz Fuertes have been reproduced from " Citizen Bird," by Mrs. Wright and Dr. Coues, published by the Macmillan Company. Figures of the types used in the outline of laboratory work have been purposely avoided. Finally, the authors have to thank several secondary teachers who have kindly made suggestions and helpful criticisms on the outline of laboratory work and the main text. We solicit a continuance of these favors to the end that this book may become as perfectly adapted as pos- sible to the needs of secondary instruction in zoology. C. B. DAVENPORT. GERTRUDE C. DAVENPORT. CHICAGO, May 19, 1900. CONTENTS CHAPTER I PAGE THE GRASSHOPPER AND ITS ALLIES. . . ' . . . . 1 Key to the four principal families of Acrididae .... 2 APPENDIX : Key to the principal families of the Orthoptera . 14 CHAPTER II THE BUTTERFLY AND ITS ALLIES . iv . ".- . . . 15 APPENDICES : Key to the principal families of Lepidoptera . 41 Key to the principal families of Hymenoptera . . .42 CHAPTER III THE BEETLE AND ITS ALLIES . .... . . .44 APPENDIX : Key to the principal families of the Coleoptera . 58 CHAPTER IV THE FLY AND ITS ALLIES . . . . .. ... 62 APPENDIX : Key to the suborders of Diptera . . 62 CHAPTER V LlTHOBIUS AND ITS ALLIES ..... . . . . 74 APPENDIX : Key to the principal families of the Myriapoda . 78 Key to the commoner species of the genus Lithobius . . 79 CHAPTER VI THE SPIDER AND ITS ALLIES . . .. . . , . . . 80 APPENDIX : Key to the seven suborders of the Araneina . . 95 ix X CONTENTS CHAPTER VII / PAGE THE CRAYFISH AND ITS ALLIES . . . . . . . 97 APPENDICES : Key to the six chief orders of Malacostraea ' . 122 Key to the principal families of Podopthalinata . . . 122 CHAPTER VIII THE DAPHNIA AND ITS ALLIES . . . . . . ' . 125 APPENDICES : Key to the five orders of Entomostraca . ' . 131 Key to the principal families of Cladocera . . . . 131 CHAPTER IX THE EARTHWORM AND ITS ALLIES . . . . . . . 133 APPENDICES : Key to the principal species of Earthworms of the United States <. .143 Key to the principal families of aquatic Oligochseta . . 144 CHAPTER X NEREIS AND ITS ALLIES . ... . . . . . 145 APPENDIX : Key to the more important families of Polychseta . 159 CHAPTER XI THE SLUG AND ITS ALLIES . ,. 160 Key to the three orders of Gastropoda 160 Key to the principal families of American Pulmonata . . 161 APPENDIX : Key to the principal families of marine shelled Gastropods of the Atlantic coast of the United States . .174 CHAPTER XII THE FRESH-WATER CLAM AND ITS ALLIES . . ... . 178 APPENDIX: Key to the principal families of marine Lamelli- branchiata of the east coast of the United States . . . 188 CHAPTER XIII THE STARFISH AND ITS ALLIES . . . . . . . 192 APPENDIX : Key to the principal classes of Echinqdermata . 203 CONTENTS XI CHAPTER XIV PAGE HYDRA AND ITS ALLIES . . . . . . . •. . ' • . 205 APPENDICES : Key to the principal subdivisions of the Cnidaria 220 Key to the families of the Hydroinedusae . . .. . 220 CHAPTER XV THE PARAMECIUM AND ITS ALLIES . . .... . 222 APPENDICES : Key to the four classes of Protozoa . . . 229 Key to the subclasses and orders of Infusoria . . . 229 CHAPTER XVI THE SMELT AND ITS ALLIES - . 230 APPENDICES: Key to the principal orders of fishes . - . . 252 Key to the six suborders of Teleostei 252 CHAPTER XVII THE NEWT AND ITS ALLIES ........ 254 APPENDICES : Key to the orders of Amphibia .... 266 Key to the families of Urodela . . . . . . 266 CHAPTER XVIII THE LIZARD AND ITS ALLIES . 268 APPENDIX : Key to the four orders of Reptiles . * •.,-••" . . 280 CHAPTER XIX THE ENGLISH SPARROW AND ITS ALLIES. . . . ^r . 281 APPENDICES : Key to the orders of Birds . . . . " . . 314 Key to the families of Passeres of northern United States . 315 CHAPTER XX THE MOUSE AND ITS ALLIES ... ... . • • • 318 APPENDIX: Key to the orders of Mammalia "... . 331 CHAPTER XXI THE DEVELOPMENT OF THE FROG'S EGG 332 Xll CONTENTS APPENDIX I PAGE OUTLINE OF LABORATORY WORK IN ZOOLOGY . , . . 337 INTRODUCTION . ".. . . . . . - . . . . . 337 EXERCISES . ". . . . , . . ... ..*...... . 342 I. Grasshopper . . . . . • . . -' . 342 IT. Butterfly . . . . - . .... 343 III. Beetle . 344 IV. Housefly or Bluebottle Fly . . ... . 345 V. Lithobius . ." . . . . . , . 347 VI. Spider . ... . . / . . 348 VII. Crayfish . . . . . . ' .. . . 349 VIII. Daphnia . . . . . . . . - . 351 IX. Earthworm . . . . . .- .' .-. . 352 X. Nereis .... . ... . 353 XL Slug . . ..... .-.-.'.. 354 XII. Fresh-water Clam . ..'356 XIII. Starfish . . . ..'.'. . .357 XIV. Hydra . • . : . . . . . . . 358 XV. Paramecium . . ... . . . 359 XVI. Smelt s ' . . . . . . . ^ . 361 XVII. Newt ... ..'.... . . 362 XVIII. Lizard . . ' - _. • . ... . . J , . .363 XIX. "English" Sparrow , . . . . .364 XX. Mouse . . . . . . ... 365 XXI. Development of the frog's egg .. . . . . 366 METHODS OF EXAMINATION . . . ... . . 367 APPENDIX II A LIST OF BOOKS DEALING CHIEFLY WITH THE ECOLOGICAL AND SYSTEMATIC ZOOLOGY OF AMERICAN ANIMALS .... 369 APPENDIX III SYNOPSIS OF THE ANIMAL KINGDOM . . . . . . 383 GLOSSARY .' . . . . . V .... 391 INDEX . 397 INTRODUCTION TO ZOOLOGY INTRODUCTION TO ZOOLOGY CHAPTER I THE GRASSHOPPER AND ITS ALLIES Relationships. — The grasshopper belongs to an order of insects called Orthoptera.1 In this group of insects2 there is an incomplete metamorphosis during development, so that the general form of the young resembles that of the adult. The anterior and posterior pairs of wings are unequal. The jaws are adapted for biting. The name " grasshopper " is applied to two families of insects ; namely, the Acrididse3 and the Locustidse. Both of these families have long hind legs, used in jumping, an elongated body flattened from side to side, and a wedge- shaped head directed downward ; they differ in the length of the antennae. Habits. — The Acrididae, or short-horned grasshoppers, are found in both hemispheres. They live, for the most part, on the ground in very diverse conditions, such as in low, damp meadows or in dry uplands, arid deserts, and rocky mountain sides. They are all herbivorous, and may 1 6/>067TTepos, with straight (lying straight out) wings. 2 The principal families of Orthoptera may be distinguished by the key in the Appendix to this Chapter, p. 14. 3 aKptdtov, a small grasshopper of Dioscorides. 2 ZOOLOGY feed upon almost any green part of plants. Some of thu species are gregarious (i.e. go in swarms) and may be very destructive.1 Melanoplus 2 is the prevailing genus of North America and covers nearly all of the continent. While in the East certain species of the genus Melanoplus may become destructive to vegetation, the injury done is not so great as was formerly done by the Rocky Mountain locust. At various times for some cause, probably drought, this locust has migrated eastward from its mountain home in countless millions and devastated our Western States as far as the Mississippi River. In 1878 to 1877 the Rocky Mountain locust was so destructive to vegetation in the trans- Mississippi region that Congress appointed a commission to investigate the species. In describing its effect the commission reports : — " Falling upon a cornfield, the insects convert in a few hours the green and promising acres into a desolate stretch of bare, spindling 1 The following key will aid in determining the four principal Ameri- can subfamilies of the Acrididse : — a\. Feet without a claw-pad. Pronotum covering all the body. Fore wings lobe-like . . . Tettigidw (Tettix Shorthorns) #2. Feet with a claw-pad ; antennae longer than an- terior femora. 61. Prosternum without a spine. d. The plane of the vertex of the head meet- ing the plane of the front of head at an angle, the face looking down . ." . Tryxalidce (Angle-headed Shorthorns) GZ- The planes of the vertex and head round over into each other . , . . (Edipodce b%. Prosternum with prominent spine . . . Melanoplidce (Thorn-throated Shorthorns) s, black ; forXa, armor. THE GRASSHOPPER AND ITS ALLIES 3 stalks and stubs. . . . Their flight may be likened to an immense snow-storm, extending from the ground to a height at which our visual organs perceive them only as minute, darting scintillations, leaving the imagination to picture them indefinite distances beyond. ... In alighting, they circle in myriads about you, beating against everything animate or inanimate ; driving into open doors and win- dows; heaping about your feet and around your buildings, their jaws constantly at work, biting and testing all things in seeking what they can devour." The locusts of the Old World are likewise frequently very destructive. The species that lives in southern Europe, North Africa, Asia Minor, Syria, Java, and Japan is doubtless the locust of the Bible. The description given by the prophet Joel is very vivid and accurate : — " A day of darkness and of gloominess, a day of clouds and of thick darkness, as the morning spread upon the mountains ; a great people and a strong ; there hath not been ever the like, neither shall be any more after it, even to the years of many generations. A fire devoureth before them, and behind them a flame burneth : the land is as the garden of Eden before them, and behind them a desolate wilder- ness ; yea, and nothing shall escape them. The appearance of them is as the appearance of horses ; and as horsemen, so shall they run. Like the noise of chariots on the tops of mountains shall they leap, like the noise of a flame of fire that devoureth the stubble, as a strong people set in battle array. Before their face the people shall be much pained ; all faces shall gather blackness. They shall run like mighty men ; they shall climb the wall like men of war ; and they shall march every one on his ways, and they shall not break their ranks. . . . They shall run to and fro in the city ; they shall run upon the wall ; they shall climb up upon the houses ; they shall enter in at the windows like a thief." General Development of the Grasshopper. — The common red-legged grasshopper lays its eggs during the fall in holes in the ground which the female drills by means of 4 ZOOLOGY the horny plates at the tip of the abdomen. The eggs, thirty to one hundred in number, are laid in a mass and covered with a gelatinous secretion. In these holes, an inch or so below the surface of the ground, the eggs pass the winter and hatch out in early summer into young grasshoppers, looking like adults except for their small size and the absence of wings. As they grow larger they moult several times, i.e. cast off their cuticular coverings. After each moult the body is left soft and colorless, but being freed of its hard, tight casement, it is in a condition to grow rapidly. After each moult also the rudimentary wings (wing-pads) become larger, and the relative sizes of the parts of the body change. Just before the last moult the pupa crawls up some vertical object, clutches it firmly with the hind feet, and remains motionless in this position for several hours. Then the cuticula splits along the middle of the back, the head and body inside the cuticula swell, the head emerges from the case, and gradually the entire body works forward out of the old cuticula ; not easily, indeed, but with violent contortions and pullings. The legs and antennse are especially difficult to free ; they can pass out of the joints of the old skin only because they are soft and flabby ; but as soon as they become exposed to the air their surface secretion hardens into a firm covering. The wings are at first rolled up ; they now expand broadly, dry, and then fold up in the way we see them in the adult. Allies of the Grasshopper. — The Gryllidae,1 or crickets (Fig. 1), include cosmopolitan insects that have short, cylindrical bodies and live chiefly in hidden places, such as beneath stones or in holes which they make in the 1 Name derived from sound made by crickets. THE GRASSHOPPER AND ITS ALLIES ground. Their eggs are laid loosely in these retreats. They feed on plants and, if numerous, may be decidedly injurious to vegetation. They make a familiar chirping noise, the blended sounds of which, as heard on a sum- mer evening, rise and fall in a distinct rhythm. The rate of chirp seems to be entirely determined by temperature, so that one may compute the temperature by means of the formula JV_4Q FIG. 1.— Gryllus, J- = 50 -j , cricket. Nat. size. Photo, by W. H. in which T stands for temperature, and c- p- N the number of chirps per minute. The mechanism by which the chirp is produced is as follows : Near the mid- 1 die of each of the upper wings of the male cricket is a vein so modi- lkJl& fied as to form a sort of file, and ^1 B4 near tne margin of the wing is a ^.^^HjN^ thickened scraper. When the up- *^B^P per wings are brought in contact ^^ jM above the body, and the scraper of ^^ fH^^^*"* one *s rubked across the file of the tjSf other, the wings are set in vibration, ylf producing the call. Jf . An aberrant form of Gryllidse is the mole cricket (Fig. 2), whose fore feet have become much modi- fied for burrowing. The Locustidae,1 or long-horned FIG. 2. — Gryllotalpa bore- alis, mole cricket. Nat. size. Photo, by W. H. C. P. 1 From the Latin name for the locust and grasshopper, as well as the lobster. 6 ZOOLOGY grasshoppers and katydids, are close allies of the short- horned grasshoppers already denned. Next to the numer- FIG. 3. — Orchelimum, meadow grasshopper. Nat. size. Photo, by W. H. C. P. ous meadow grasshoppers (Fig. 3) belonging to this group, the katydids are the best known of its representatives. The katydids have their whole body green, like the foliage they FIG. 4. — Ceuthophilus, cricket-grasshopper. Two-thirds nat. size. Photo, hy W. H. C. P. inhabit. The wings are large; and when the upper wings are rubbed together, they vibrate, and cause the familiar THE GRASSHOPPER AND ITS ALLIES note. Other members of this group are the cricket-grass- hoppers (Fig. 4), wingless forms, of a brown color and arched profile, which live under stones and rubbish, and also the cave " crickets," which are colorless and blind. The Phasmidae^or walking-sticks and leaf-insects, display, to a mar- vellous degree, a protective resem- blance to the twigs and leaves among which they live. The most remark- able forms live in the tropics. They have large wings, which strikingly resemble, in form, color, and vena- tion, either living or dry leaves. Upon those species which resemble dried leaves, blotches looking like fungous patches are found. Even the legs may be thin and expanded, resembling foliage. In our country only the twig-like, wingless forms, or walking-sticks, occur. These in- sects are furthermore protected by changes in color, corresponding with the seasonal color changes in twig's : , o » ' FIG. 5.— Diapheromera, walk- for the young walking-sticks, which appear in the spring, are green like the twigs, but in the autumn they become gray or brown. Figure 5 shows our only common northern species, Diapheromera femorata. It feeds on leaves, especially those of the oak, and occasionally does much damage to trees. ing-stick of northern U. S. Nat. size. Copied from Packard. appearance, spectre. ZOOLOGY The Mantidae1 are popularly called praying-mantis, on account of the devotional attitude in which the greatly en- larged front legs are held. Unlike other Orthoptera, they FIG. G. — Phasmomantis Carolina. Praying-mantis of southern U. S. Nat. size. Copied from Packard. are carnivorous. They hunt and devour other insects some- times larger than themselves, and even prey upon each other. While most of the species are tropical, one species, PJiasmo- manfis Carolina (Fig. 0), is abundant in our Southern States, and another occurs in the Missouri valley. The Blattidae,2 or cockroaches, are especially* creatures of the tropics ; and those which live in colder cli- mates frequent warm as well as dark places. The two which are our household pests have been imported from Europe, — both the small brown " Croton bug," which is found among water-pipes in the kitchen, and the large black species commonest in sugar-refineries, slaughter- houses, and bakeshops. They are omnivorous, eating, FIG. 7. — Wingless cock- roach. Nat. size. Photo, by W. H. C. P. , seer, prophet. 2 llatta, roach of Pliny. THE GRASSHOPPER AND ITS ALLIES 9 among other things, breadstuffs, clothing, book-bindings, bedbugs, and other insects. We have also a number of native cockroaches, which live chiefly in fields and woods, under stones and logs. Some of these are wingless (Fig. 7). The following groups are frequently excluded from the Orthoptera, but show a certain relationship with them : — The Forficulidae,1 or earwigs, are rare in the northern United States, but commoner in the Gulf and Pacific States. In general appearance they resemble rove-beetles, but differ from them in having a pair of forceps at the posterior end of the body. They hide, during the day, in the corollas of , ,^j FIG. 8. — Two North American Odonata, belonging to the family Libellululro. About one-half nat. size. Photo, by V. H. L. flowers, upon which they feed, and fly about at night. The name earwig seems to have arisen from an unwarranted belief that these insects penetrate into the ears of persons when asleep. They were especially dreaded on account of a fear that they might thus penetrate into the brain. The Odonata,2 or dragon-flies, have four membranous, net- veined wings, of which the front pair are never larger than the hind ones. Their large heads carry relatively enormous eyes. Two groups of dragon-flies may be distinguished according as the wings, at rest, are extended (Fig. 8) or 1 forficula, a small forceps. 2 (55ous, tooth, from the teeth of the mandibles. 10 ZOOLOGY folded together over the back. Dragon-flies live on the wing, hovering over water and preying upon other insects, especially mosquitoes. The eggs develop in the water into aquatic larvse which are f quite unlike the adult. Especially the jaws are peculiar, being jointed and capa- ble of sudden protrusion, in order to catch the animals which serve as prey. These larvae are easily reared over winter in an aquarium, where not only their ferocious habits, but also their peculiar method of breathing by means of water taken in at the anus, may be observed (Fig. 9). The Ephemeridee,1 or May-flies. The adult May-fly possesses finely veined fore wings, which are much larger than the hind wings. The mouth parts are rudi- mentary arid the abdomen terminates in two or three filamentous appendages. As their systematic name implies, they have a very ephemeral existence in the imago state. The imago appears in swarms early in the summer and lives but a few hours, eating nothing and depositing eggs upon or under stagnant water. The larvse feed upon small aquatic plants and insects, breathe by means of gills placed on the back, and live for nearly a year, or even for two or three years, in the immature stages. After many moultings the apparent adult emerges, but, unlike other insects, undergoes an additional moult before laying its eggs. As the insect is subjected to many accidents in its long and defenceless life, each species is preserved only by an enormous fecundity. , a day, i.e, lasting but a day, short-lived. FIG. 9. — yEschna, old larva, or pupa. Nat. size. Photo, by W. H. C. P. THE GRASSHOPPER AND ITS ALLIES 11 White ants, or termites (Fig. 10), while not true ants, live a very similar social or communal life. They differ from ants in the venation of the net-veined wing (when present). White ants are most abundant in the tropics, where they build great conical nests of sand cemented by their saliva ; but they are found also in temperate countries. The common eastern white ant (Termes flavipes} ranges from _. ' r • °. . FIG. 10. - Termes Massachusetts southward, and lives in jiavipes, white wood or under stones. Three kinds or " ant-" Nat- size. Photo, by castes of white ants occur in any com- w. H. c. P. munity : (1) workers, with small, round heads and concealed mandibles ; (2) soldiers, with large, square heads, and long, powerful mandibles ; and (3) the royal class of kings and queens, which have wings until after the marriage flight. At a certain time in May the males and females from the various colonies fly forth to mate, and thus an interbreeding takes place between colonies. Only a few of the pairs, however, find workers to aid them in establishing a new colony. The queen, after she is established in a new hive, merely produces young, the abdomen becoming immensely swollen and elongated to fifteen centimetres with the eggs which are about to be laid. In tropical countries the termites are troublesome to man by injuring trees and devouring the woodwork of houses. The order Neuroptera includes certain insects which differ from the Orthoptera in having larvae very unlike the adult, and in having a resting pupal stage in which the metamorphosis into the adult is completed. There are four membranous, clear, net- veined wings, and the mouth ZOOLOGY parts are used for biting. The largest representative of this group is the Horned Corydalis (Fig. 11), whose larva lives in streams and is called the dobson. The adult is found among fallen leaves or on tree trunks. The order Hemiptera includes certain insects which resemble the Orthoptera in \ FIG. 12. — Hygrotrechus, water-strider. Nat. size. Photo, by W. H. C. P. undergoing an incomplete metamorphosis; i.e. in having larvae much like the adults in form, and in having no quiet pupal stage. They differ from the Orthoptera in possessing mouth- parts adapted to FIG. 13. — Reduvius, the assassin bug. Black. Nat. size. Photo, by W.H. C. P. FIG. 11. — Cory- dalis, the dobson. Two -thirds nat. size. Photo, from life by W.H.C.P. sucking. The True Bugs (Heteroptera) in- clude a vast number of generally small insects with very varied habits. Some of them swim through the water and are known as water boat- men ; others skip over the surface of the water and are known as water- striders (Fig. 12). Others, like the THE GRASSHOPPER AND ITS ALLIES 13 Squash Bug, are destructive to plants ; still others, like the Reduviidse, kill injurious insects (Fig. 13). [••^^•^^••••••^••^•^^^^•IggBI^^BB F:G. 14. — Cicada septemdecem, the seventeen year locust. Reduced, Photo, hy V. H. L. FIG. 15. — Pupal case of cicada. Two- thirds iiat. size. Photo, by W. H. C. P. FIG. 16. — Locanium, a scale insect. Remains of females after production of young ; seen as swellings on the bark. Nat. size. Photo, by V.H.L, 14 ZOOLOGY The Homoptera include insects of very diverse size and form. The largest are the cicadas, or "locusts" (Fig. 14), some of which have the remarkable habit of requiring thirteen or seventeen years for their development. Con- sequently these cicadas appear only at intervals of thirteen or seventeen years. The young bury themselves in the ground and live by sucking juices from the roots of trees. Eventu- ally they come to the surface, leave their lar- val skin (Fig. 15), and fly away as full grown cicadas. In the case of our common species of cicada there is a brood every year. Besides the cicadas the Homoptera include the little leaf-hoppers and tree-hoppers, the very destructive scale- bugs (Fig. 16), and the mealy-bugs, most of which attack fruit trees and their fruits, and the plant-lice, or aphids (Fig. 17). FIG. 17. — Schizoneura, a woolly aphis, on apple twig. Photo, by V. H. L. APPENDIX TO CHAPTER I KEY TO THE PRINCIPAL FAMILIES OF THE ORTHOPTERA a\. Legs similar, fitted for running . , ; . , Blattidce (Cockroaches) «2- First pair of legs differentiated for grasping ; pro- thorax elongated . ; . • . . . Mantidce (Praying-man ti s) APPENDIX TO CHAPTER I 15 «3. Legs similar, much elongated, and fitted for slow walking ......... Phasmidce (Walking-sticks) a*. Hinder legs stouter or longer than middle pair. 61. Antennae shorter than body V .* . . Acrididce (Locusts and Short-horned Grasshoppers) &2- Antennae longer than body. GI. Tarsi 4-jointed . . . . . . Locustidce (Katydids and Long-horned Grasshoppers) c2. Tarsi 3-jointed Gryllidw (Crickets) CHAPTER II THE BUTTERFLY AND ITS ALLIES Systematic Position. — Butterflies belong to the insect order Lepidoptera,1 characterized by the possession of a long, coiled, sucking proboscis; large, membranous wings, covered with colored scales; and a complete metamorphosis. They occur over the whole globe, but become more numer- ous in species in the tropics of South America and Africa. The number of known species is about twenty-five thousand.2 The Habits and Food of Butterflies. — The idea of a butterfly should not be limited to the winged adult called the imago, for strictly we may call a caterpillar a larval butterfly, and a pupa an adolescent butterfly. But in its different stages the habits and food of a butterfly change. Caterpillars feed, for the most part, upon plants. A few — such as the clothes-moth and certain enemies of scale in- sects— feed upon animal matter. Any single species of caterpillar feeds upon the foliage of a restricted number of kinds of plants. At one extreme we have forms which starve unless they can reach their own particular food plant; at the other extreme there are caterpillars which can live upon the foliage of many kinds of plants, and these are consequently called polyphagous. Certain fami- 1 Xe7r/s, scale ; irrepbv, wing. 2 The principal families of Lepidoptera may be distinguished by the key in the Appendix to this Chapter, p. 41. 16 THE BUTTERFLY AND ITS ALLIES 17 lies of plants especially serve caterpillars as food. Thus of the hundred species of New England butterflies, eight feed upon oaks, eleven upon willows, thirteen upon the Rosacese, and twenty-eight upon leguminous plants. It follows from the restricted food of many caterpillars, that the range of the species must often be determined by that of its food- plant. The feeding of the butterfly is mostly done in the larval stage : the pupa can take no food. The imagos of many species touch no food, but in other cases they take small quantities of the nectar of flowers, the sap of plants, and the juice of fruits. The imagos fly in the daytime, especially in the sun- shine. Certain species are characteristic of the roadside, others of meadows, gardens, or woods, while still others are found flying everywhere. Owing to its ordinarily short life, the imago is usually found not far from the larval food-plant, upon which it lays its eggs. The Broods of Butterflies and their Polymorphism. — Butterflies winter over in various stages, some in the egg stage, some as larvse, others as pupse or as imagos. Some kinds pass the winter in either of two stages. In whatever stage they tarry, the life current runs very slow, and dur- ing this season few changes take place. In the spring, development goes on rapidly : the winter generation be- comes mature and a summer generation is started. Fre- quently there is more than one brood produced during the summer, even in the Northern States. Farther south two and even three summer broods are- still commoner. Where two or three broods occur they may be and usually are quite dissimilar. This is very strikingly illustrated in the case of the Zebra Swallow-tail, Iphiclides (JPapilio) ajax, 18 ZOOLOGY of the southeastern United States, which is multiple- brooded. The early spring form (marcellus form) is the smallest, and has the tail tipped with white; the summer form (ajax) is the largest, and has the tail two-thirds longer than the marcellus form. Other illustrations of this seasonal difference are given by the imported Cabbage Butterfly, the Gray-veined White and the Spring Azure. This dissimilarity between the broods of different seasons is known as seasonal dimorphism or polymorphism. The cause of the difference between the different broods seems to be the dissimilar climatic, especially thermic, condi- tions under which they have developed. Mr. W. H. Edwards in this country, and Weismann and others in Europe, have shown that, when the summer form is kept during development in a refrigerator, the butterfly has the color of the winter form. Protective Resemblance and Mimicry. — Every one who has visited a natural history museum must have noticed that the polar mammals are apt to be more or less white, while those which live in tropical forests are dark. It is easy to understand that these colors in their proper sur- roundings make the animals which wear them hard to see. This may be of advantage in enabling them to escape the observation of their enemies, which are seeking for them, or to avoid being seen by their prey as they ap- proach. This general resemblance to their background is seen even in some caterpillars, e.g. the tomato-worm, which is colored so exactly like the leaf on which it feeds that it is hard to find. Other caterpillars, belonging to the geo- metrid moths, have the color of the twigs of the plant on which they feed, and the resemblance is heightened by the way they have of stiffening and standing out like a branch THE BUTTERFLY AND f!T8 ALLIES 19 from the stem. The moths of the genus Catocala,1 which fly by night, rest by day on the bark of trees, which they so resemble as to be almost indistinguishable. Still more striking is the resemblance which we find between some adult butterflies and dry leaves as seen, for example, in Kal- lima, a butterfly of the East Indies.2 The resemblance of the butterfly to the leaf extends even to details, for the clear patches on the wing resemble holes, while little cir- FIG. 18. — Catocala ilia, the underwing. Upper wings, bark color ; lower wings, black with orange bands. Photo, by C. Bullard. cular markings resemble the patches made by particular kinds of fungi. This resemblance of an organism to in- animate objects in its environment is known as protective resemblance. There are certain species of butterflies which appear to be let alone by birds, owing to their disagreeable odor or acrid taste. Examples of such are "the Heliconidse, char- acteristic of tropical South America, and the Danaidse, to which family our " Monarch " belongs. Closely resembling 1 Fig. 18. 2 Fig> 19. 20 ZOOLOGY the Monarch in this country is the " Viceroy," Limenitis archippus. This resemblance of the edible Viceroy to the inedible, acrid Monarch, it is believed, is sufficient to FIG. 19. — A, Kallima, the leaf-butterfly of the East Indies, flying; a, at rest. B, Siderone, another leaf-butterfly, flying; b, at rest. deceive even the birds, and thus the Viceroy gains con- siderable immunity from attack. This resemblance of an edible to an immune species is known as mimicry. The origin of protective resemblance and mimicry are both THE BUTTERFLY AND ITS ALLIES 21 explained by the theory of Natural Selection or Darwin- ism. Since either of them is of great utility to the organism, their possession, even to a slight degree, how- ever accidentally gained, will give their possessor an ad- vantage over its neighbors in the Struggle for Existence. Consequently it will be more apt to survive and transmit its peculiarity to its offspring. By this means an adapted race will arise and crowd out the unadapted. Types of the Butterflies. — The group Papilionidse in- cludes the butterflies which fly by day. An account of the most important follows. The Papilios (Swallow-tails) are our largest butterflies. Here belong the yellow Tiger Swallow-tail (turnus), with black stripes, which is found over nearly the whole United States; and the black Swallow- tail (asterias), whose wings are crossed by rows of yellow spots, and whose hind wing bears an orange, black-eyed spot. Its larvse feed on wild or cultivated umbelliferous plants, especially parsnip leaves. The Cabbage-butterflies (Pieris) have white or yellow- ish wings, tipped and spotted with black, or sometimes with orange. They hover over damp spots in roads or fly through garden patches. The larvse are very destructive and feed on cabbage and other cruciferous plants. To the Nymphs belong the Angle- wings whose fore wings are notched on their outer edge. Here belongs the butterfly which we sometimes see on warm days in winter or early spring — the Mourning-cloak. This has pur- plish brown wings with a broad yellow border, and a row of pale blue spots. The Graptas belong here, too ; they may be told by the silver spot on the hind wing. In the Admirals the wings are less deeply notched. The red Admiral is purplish black above, with an 22 ZOOLOGY orange band and white spots running obliquely across the upper side of the fore wing. It occurs in England as well as in the United States. Here belongs also the Viceroy, which is not closely related, but is quite similar to the Monarch because the former mimics the latter. They are both of a tawny orange color, with a white- spotted black border on the outer wing margin. The Monarch is the larger, and like the birds has the habit of migrating southward in the fall and returning in the spring. The Fritillaries (Argynnis :) include some large butterflies, having numerous round and triangular silvery spots on the under side of the hind wing. To the Lycaenas2 belong the Blues, or Spring Azures, including small satin or steel-blue species which exhibit marked seasonable polymorphism ; the Coppers, orange- red, or brown species; and the Hairstreaks, or Theclas,3 which are small, brown butterflies, usually with two tails to the hind wing. Types of the Moths. — These include all Lepidoptera, excepting the family of Papilionidse. Seven families are of rather large size (Macrolepidoptera) ; the remaining four are of small size (Microlepicloptera). The Sphingidse,4 or Hawk-moths, fly swiftly and power- fully, and as they hover over flowers at du;jk can hardly be distinguished from humming-birds. The larvae have a caudal horn or tubercle. The commonest of these are the tomato or potato " worm," green in color and banded. There are about one hundred species of the Sphingidse in l'Apyvwls, the "silvery," a poetic name of Venus. 2 MiKouva, a poetic name of Venus. 8 A Greek feminine name. 4 From 20*7£, or sphinx, a fabled monster. The larva of this moth assumes an attitude like the sphinx. THE BUTTERFLY AND ITS ALLIES 23 the United States. The Twin-spotted Sphinx (Fig. 20), so- called from the black spots of the hind wing, is destructive FIG. 20. — Smerinthus c/eminatus, the Twin-spotted Sphinx. Nat. size. Photo, by W. H. C. P. to fruit and shade trees. The Pandorus Sphinx (Fig. 21) is of a beautiful olive color ; its larva feeds on vines. FIG. 21. — Philampelus pandorus, the Pandorus Sphinx. Nat. size. Photo, by W. H. C. P. The Xylotropidae l are chiefly medium to small, clear- winged species which fly at dusk or in daylight. Their , wood ; T/o^0w, to feed ; because the larvae feed on wood. 24 ZOOLOGY larvae live in stems of squash, cucumber, etc., and bore into shrubs and trees (Fig. 22). The Arctiidae,1 or Tiger-moths, are for the most part con- spicuously striped or spotted. The larvse are very hairy. The best known is the furry, brick-red and black Isabella caterpillar, which can be seen during October in New Eng- land, hurrying nervously in search of winter quarters. The Bombycidse2 include, as a rule, large and thick- bodied moths. Here belong the silkworm moths — the only moths of use to man. Of these, Bombyx mori3 is the most generally employed in the manufacture of silk. It originally came from China, feeds on the leaves of the white mulberry, and is reared chiefly in China, Japan, Italy, FIG. 22. — Larva of one of the Sesiidse boring in stem. Nat. size. Photo, by V. H. L. and France. The method of culture is as follows : The eggs (u grains ") are laid in the autumn, kept over winter in a dry, airy, and cool place, and hatched when the mul- berry begins to send out its leaves. On these leaves the larvse are put to feed, and after a month they begin to spin. For commercial purposes the larvae are induced 1 From dp/cTos, bear. 2 Bombyx-like. Aristotle called the rustling silk /36/x/3os ; hence the name Bonibyx for the silkworm. 3 morus, a mulberry tree. THE BUTTERFLY AND ITS ALLIES 25 to spin the cocoons on prepared twigs or straw. A few days after the cocoon is completed its inhabitant is killed FIG. 23. — Citheronla regalia, the Regal moth. Olive and red wings, yellow spots. Nat. size. Photo, hy W. H. C. P. in hot water. The cocoon is made of a continuous thread about three thousand metres long, of which, however, only FIG. 24. — Larva of Citheronia regalis. Head to left. One-half nat. size. Photo, hy W. H. C. P. about six hundred metres make good silk. This long thread has to be unravelled. The outer end is loosened 26 ZOOLOGY by soaking the cocoon in hot water ; then several of these ends are brought together and united to form a single fibre of raw silk. Another imported silk-moth common in parts of the United States is the Cynthia1 moth, whose larva infests Ailan- thus trees. True American forms are the brown Polyphemus2 moth, whose larva is colored light green, with oblique yellow stripes; the Promethea3 moth, whose cocoon is formed in a folded leaf which is securely fastened by silk threads to its twig ; the Cecropia moth, expanding six inches, whose coarse tegumen- tary cocoon is bound along its whole length to a twig; and the nearly equally large Regal moth (Citheronia regalis, Fig. 23), whose larva is oar largest cater- pillar (Fig. 24). All of these species are easily reared from the larvse or cocoons. Closely allied to the Bombycidre are the Tent-caterpillars, which are never of great size. FIG. 25. —Adult female of Cli- siocampa dis- stria. From life. Nat. size. Pho- to, by V. H. L. Fin. 20. — Adult male of Clisio- cainpa. From life. Nat. size. Photo, by V. H. L. These are FIG. 27. — Egg masses of forest Tent-caterpillar, laid on branch. Photo, by V. H. L. 1 A poetic name of Diana, from the mountain Cynthus. 2 The name of the fabled one-eyed giant blinded by Ulysses. 3 A name in Greek mythology. THE BUTTERFLY AND ITS ALLIES 27 destructive species, which infest apple trees and even forest trees (Figs. 25 and 26). Eggs are laid in a ring-like cluster around a twig (Fig. 27). Here they pass the winter and hatch out in the spring as young larvae. The larvae are gre- FIG. 28. — Nest of CUsiocampa disstria, the forest Tent-caterpillar, showing the web and the way the larvse crowd together on it. Photo, by V. H. L. garious and spin a tent-like web, on which they live when not feeding (Fig. 28). When ready to transform, they spin a cocoon made of a yellow powder mixed with silk. The Noctuidae1 (Owlet moths) are night fliers and are 1 From nox, night. 28 ZOOLOGY attracted by our lamplights. They are the most numer- ous of all our moths, eighteen hundred species being known from our country. Among the largest members of this group are the Catocala l moths already referred to. Here also are placed the boll-worm, which eats cotton-pods and green ears of maize ; the cotton-worm, which destroys the foliage of cotton ; the army-worm, which devours grass and young grain ; and the myriad cut- worms, of which some gnaw off young garden shoots at the level of the ground, while other kinds ascend trees and de- stroy buds. To the Noctuidss belong also the Tussock moth (Fig. 29), whose variegated larva bears dense brush-like tufts of whitish hairs on the first four abdominal segments, and is very de- structive to shade trees in our cities ; the Gypsy moth, lately imported into Massa- chusetts, where the state has attempted its annihilation ; and the Brown-tail moth, also lately imported to Boston. FIG. 29. — Notoiophus, The Gcometridae, or measuring-worms, Tt £X ,!S± <««, like the Noctuids, very numerous is shown below a and very destructive. They are so ^U^" called because the larva, have a way From life. Photo. of proceeding, as it were, by inches in their locomotion. One of the most im- portant subdivisions is that of the canker-worms, which often strip fruit and shade trees of their foliage. 1 /card, below ; /co\6s, beautiful. THE BUTTERFLY AND ITS ALLIES 29 The Pyralidae l include among other pests the bee-moth. The larva of this species feeds upon the wax of the hive and constructs silken galleries in the comb. The Tortricidae 2 contain numerous small, inconspicuous moths, whose larvae are, however, very destructive. The codling-moth is a pest of the fruit-grower, for the larva bores into apples and pears, causing them to fall prema- turely. Many species are called leaf-rollers, from the fact that the larva causes the leaf on which it feeds to curl. FIG. 30. — Case-bearing insects on a twig. Photj. from life by V. H. L. The Tineidse3 contain the smallest of the Lepidoptera. Their wings frequently bear long fringes. The larvae are so small that they often live in the interior of leaves, and form winding or blotch-like "mines" in them. The larvae of some species make a case out of pieces of leaves united by silk, and carry this about with them. They are known as " Case-bearers " (Fig. 30). Here also belong the clothes- 1 From Trup, fire ; because the ancients believed these insects to arise from and live in fire. 2 tortor, tortrix, winder, from torqueo, to roll or wind ; with reference to the habit of twisting up leaves. 3 tinea, moth. 30 ZOOLOGY moths, of which we have three species. These moths fly early in May, and lay their eggs on woollen cloth, furs, or feathers, upon which the larvae feed. This review of the Lepidoptera shows us that, on the whole, despite their beauty, they are great enemies of agriculture, since most of them feed on vegetable prod- ucts. Not only do we in this country have an abundance of native forms, but several exotic species have been im- ported; and being thus removed from their natural enemies, their natural fecundity has been unchecked, with the result that they have brought great devastation upon vast agri- cultural districts. The earnest attempts of a state to keep down for a while an introduced pest, even at great expense, is commendable. The Hymenoptera l include bees, wasps, ants, and certain less well-known insects. They all have four similar mem- braneous wings as the Lepidoptera do ; but unlike the Lepidoptera, their wings are not covered with scales, but are transparent. The mouth parts are formed for biting or for sucking, but the proboscis is not so long that it rolls up as in Lepidoptera. The Hymenoptera belong to one or the other of two groups, — the stinging Hymenoptera, in which the female is provided with a sting, and the boring Hymenoptera, which are provided with an ovipositor, or long tube, by which eggs can be placed at some distance below the sur- face. To the first division belong the bees, wasps, and hornets, certain digging or boring wasps, and the ants. To the second division belong certain species, — as, for example, the ichneumon flies, — which are parasitic on 1 vfj.r]i>, skin, membrane ; trrtpov, wing. THE BUTTERFLY AND ITS ALLIES 31 other insects, the gall-flies, or gall-wasps, and the plant- eating Hymenoptera.1 The bees (Apidae2) include both social species and others which lead solitary lives. Of the latter, some dig their nests in the ground ; others are masons, and build their nests of mud ; others are carpenters, and make tunnels through pithy plants, or even solid wood ; while still others are leaf -cutters. These leaf-cutting bees carve circular disks from rose leaves, out of which they make cells for their young. Of the social bees, our native species belong to the genus Bombus, — the " bumble " bees. The bumblebees build nests in the ground. The queens only survive the winter. In the spring each queen chooses some mouse nest or other ready-formed cavity in a meadow, and places within it a ball of , . „ , , FIG. 31. — Bombus, the bumblebee. pollen. Upon this tood she Nat. size. Photo, by W.H. c.r. lays eggs, which develop into worker bees. As soon as the workers are full grown they begin the task of gathering food, and the queen then de- votes all her energy to egg-laying. Later in the season males and young queens also appear in the nest. The old and young queens dwell together in harmony until autumn, when all the members of the colony perish except- ing the young queens, which pass the winter in some sheltered spot and form new colonies in the spring. 1 A key to the principal families of the Hymenoptera is given in the Appendix to this Chapter, p. 42. 2 From apis, bee. ZOOLOGY The introduced, semi-domesticated honey-bees have quite a different social economy. In the first place, the nest is perennial ; consequently the young and old queens cannot remain in the same hive, else the nest would become overcrowded by the presence of too many families. As }7oung queens mature, the old queen seeks to destroy them ; but she is usually forced out of the hive by the workers, a num- ber of which accompany her. This migration is what we call "swarm- ing." l When several young queens mature at the same time, duels or repeated swarmings en- sue until only one queen remains. When a new colony is started in a hive or hollow tree, a comb is formed of wax secreted by the worker bees, and into this the queen deposits eggs des- tined to develop into workers. Still later, eggs destined to form drones are laid in cells larger than those in which workers develop. The de- veloping young workers and drones are fed with honey and bee-bread. Honey is derived from the nectar of flowers, which is lapped up by the workers, is stored for a time in the crop, where it undergoes certain transformations, and is then 1 Fig. 31a. FIG. 'Ma. — Swarm of bees. Photo, by D. and S. THE BUTTERFLY AND ITS ALLIES 33 regurgitated into the cells. The nature of the transfor- mation of the nectar in the crop of the bee is not precisely known, but it is riot great enough to prevent the character- istic flavors of the flowers of the buckwheat, orange, and so on, from being retained in the honey. The bee-bread is made from the pollen of the flowers, which is brought into the hive on the hind legs of the workers. When a new queen is needed for the colony, and the queen cells are empt%y, one may be produced by the workers in the fol- lowing manner : The partitions between three worker cells are destroyed and two of the embryos are killed. The enlarged cell is filled with a special nutritive compound manufactured by the workers and known as royal jelly. The remaining embryo, fed upon this especially nutritious jelly, develops, not into a worker, but into a queen. Of the true wasps (Vespidie *), some are solitary; others, like certain of the bees, rear their families in the nests of other species (guest-wasps) ; while still others are social. The last group includes our best-known species. The colony of social wasps contains males, females, and workers. As in the case of bumblebees, only the females survive the winter, and in the spring they build small nests and lay worker eggs. The workers, when grown, FIG. 32.— Poiistes. enlarge the nest and care for the numerous Slightly reduced. . , , ~ . , Photo, by W. H. progeny or the queen. Our social wasps c. P. belong either to the genus Poiistes,2 which includes the ordinary black, brown, or yellow bodied wasps, which build mushroom-shaped nests behind window blinds and under boards (Fig. 32), or to the genus Vespa, 1 From vespa, wasp. 2 TroXio-r^s, founder of a city. 34 ZOOLOGY FIG. 33. — Vespa, a hornet. Nat. size. Photo, by W. H. C. P. which includes the black and spotted hornets and yellow- jackets, that build great masses of paper combs enclosed in a nearly spherical gray paper envelope (Fig. 33). These are found attached to trees or parts of buildings. The paper is made of finely masticated wood-fibre cemented by a secretion. Certain yellow- jackets form nests in the ground. The hornets are well known as among the most vindic- tive of our northern insects, and their sting is capable of produc- ing considerable pain. In all Hymenoptera the pain of the sting is due to the introduction of a poison into the body of the victim through the stinging organ. This poison is secreted by a special gland of the insect. The digger and mud wasps (Fossoria1) have the most varied habits. One of the most familiar species is Pelo- pceus,2 which somewhat resembles a true wasp, but may be easily distinguished from it by the long, slender attachment of the abdomen to the thorax and by the fact that the wings when closed lie flat and horizontal (Fig. 34), while in the true wasps they are folded like a fan. FIG. 34. — Digger Other species bore into the pith of plants or make burrows in the ground. Many are predaceous, feeding on spiders, cicadas, etc. The ants (Formicidse 3) constitute a well-known group having features so marked that other insects, excepting 1 From fossor, digger. 2 71-77X65, slime. 3 From formica, ant. wasp, showing po- sition of wings. Nat. size. Photo, by W. H. C. P. THE BUTTERFLY AND ITS ALLIES 35 the termites, will hardly be confused with them. From the termites ants may be distinguished by the fact that the first segment of the abdomen forms a small knot or scale lying between the thorax and the remainder of the ab- domen (Fig. 35). The intelligence of ants is notorious. This intelligence has developed in connection with a highly organized social life. This social life is a communistic one. Homes are built, food is gathered, \vars are made, and domains arc defended bravely and loyally all for the sake of the entire community. The individual is little regarded, and each FIG. 35. — Camponotus, the carpenter ant. Uniformly black. Shows scale behind thorax. Nat. size. Photo, by W. H. C. P. one is born to a caste from which escape is impossible. For, in addition to the distinction of sex characteristic of other species, we have here workers, and these workers may be of different kinds. Thus certain workers get food and care for the young; others, which serve as soldiers and defend the colony or conduct war, are in some cases pro- vided with powerful jaws. In some species there are three or more classes of workers, each having its characteristic form of body. Ant Colonies. — A colony is founded by a female. On warm days the young males and females may leave the nests and take flight in great numbers. This is the mar- riage flight of the queens. Within a few hours after 36 ZOOLOGY nightfall of the day of this flight the males perish, while the queens settle down to the ground, tear off their wings, and each of them seeks an appropriate place to begin the formation of a new colony. If by chance a queen is dis- covered by some of her workers, she is cared for by them; otherwise she must get on alone. She makes a small nest and lays eggs, which quickly develop into workers, which then assume the task of constructing the nest of the new colony. The nests of our ordinary species consist simply of tunnel-like passageways dug in the ground and enlarged at intervals to form small chambers. Most species dig their nests preferably under protecting stones or the roots of trees ; in other cases a hillock of earth and twigs, an "ant-hill," is constructed. These mounds may attain a diameter of from six to ten feet. Ant Language. — In connection with their communal life ants have gained a power of communication. By the agency of their antennse, with which two comrades are constantly stroking each other, they can tell each other of the whereabouts of food, of the approach of an invading army, or of the need of aid. They distinguish members of their own community from those of other communities, and recognize one of their number, even after a long ab- sence, and receive it back to the colony with demonstrations as of joy. Social Life of. Ants. — To illustrate the complex social life of ants, a more detailed account is here given of certain interesting species. Certain ants, such for instance as our Formica 1 difficilis^ a rust-red species often found living beneath large, flat stones, make slaves of another species of ant which (a curious coincidence) is a dark-colored species. In at least one slave-making species the jaws have become i Ant. 2 Difficult. THE BUTTERFLY AND ITS ALLIES 37 so modified to aid it in capturing slaves that it is absolutely dependent upon its slaves for food, and it would die surrounded by food were none of its slaves at hand to feed it. The Agricultural Ant. — One of our most interesting ants is the Agricultural Ant of Texas (Myrmica l molefaciens 2). This ant makes a circular clearing about its mound, upon which it allows only one species of grass to grow. Indeed, some observers maintain that the seed of this grass is planted upon the clearing by the ants. Certain it is that the ripe seeds of the grass are carefully harvested by the ants and stored within the chambers of their mound. From time to time the seeds are brought out and dried to prevent sprouting. During rainy sea- sons, when the seeds germinate despite all pre- cautions, the ants are said to nip off the sprout upon its first appearance. The army ants, of which there are several species, occur in great numbers in tropical South America. Like many other species which live by hunting, they migrate from a locality after having exhausted it of their food. While on the inarch, the young of the species are trans- ported by some of the adults. When an army of these ants approaches a place, every living animal endeavors to escape. The breeding birds must be on the alert to pick off the advance Fl,a W.—Pimplapeda- hs, a parasite on the guard to prevent them from returning to the caterpillar of Clisio- ar my with news of the presence of nestlings. campa. Upper figure Insects of all sorts, young and old, fall a ready prey to these swarms. Some spiders escape by suspending themselves by their threads, and insects which resemble leaves often find safety in keeping rigidly still. When an army of these ants enters a house, the inhabitants find it wisest to leave the invaders in possession, for in a few hours the house is cleared of every living thing — moths, cockroaches, rats, mice, all have fled or been devoured. The leaf -cutting ants are another tropical American species. The , ant. 2 Mole or mound builder. 38 ZOOLOGY colony is very perfectly organized. The duties of the workers are divided among different gangs. Thus, when a tree has been selected, one gang ascends the trunk and cuts the leaves in pieces of a definite shape. The pieces flutter to the ground, are picked up by another gang and carried to the entrance of the ant-hill, where they are de- posited to be carried into the nest by a third relay. The bits of leaves are used to line certain of the passageways, and a fungus is grown upon them which serves the ants as food. The leaves are probably stored to provide this fungus food. The parasitic Hymenoptera have the habit either of lay- ing eggs in the body of another insect, — one of the plant- lice, a caterpillar, or other species, — or else they lay their eggs in the nest of some species of insect so that the larva can make its own way into the host (Figs. 36-38). The long, tail-like ovipositors of the female ichneumon are, in some cases, used to drijl holes into trees occupied by insect burrows so that her eggs can be laid therein. These parasitic species are invaluable to agriculture in keeping down injurious insects. The gall-wasps, popu- larly not distinguished from the strict gall-flies, are familiar to us from their works. They lay eggs in various kinds of plants, especially in oaks and members of the rose family. An excessive growth of the plant tissue, called a gall, is caused either by a poison dropped into the plant with the FIG. 37. — Cocoons of Microgaster, a para- sitic hymenopter, on a sphinx larva. Photo, from the living object by V. H. L. THE BUTTERFLY AND ITS ALLIES 39 egg, or by the irritation of the developing embryo.1 The galls of gall-wasps are often more or less spherical masses FIG. 38. — Ophion, an Ichneumon which infests caterpillars. Nat. size. Photo, by W. H. C. P. which are closed, in consequence of which the confined insect must bore its way out. The galls made by the same FIG. 39. — Larvae of saw-fly on grape leaf. Photo, by V. H. L. 1 Cf. Fig. 69, p. 67. 40 ZOOLOGY species of insect on one kind of tree are quite similar, but if the same insect stings another species of tree, a different kind of gall is produced. Also when different species of gall-wasps sting one and the same leaf, the galls will be unlike. Hence the characteristic form of the gall is determined both by the species of plant and by the species of insect which lives in it. It is interest- ing to collect galls, watch for the emerging wasps, determine their species, and thus get their entire life history. The gall- wasps are, on the whole, injurious to agriculture. The plant-eating Hy- menoptera are extremely destructive pests. The young are known as "slugs," from their re- semblance to the true slugs, which are snail-like animals. They infest pear trees and rose bushes, leaving scorched, dried leaves behind them.1 Here also belong the currant-worm and the saw- flies (Figs. 39 and 40), which eat leaves like caterpillars, but differ from them in having twelve or sixteen prolegs instead of ten. FIG. 40. — Eggs of Nematus, a saw-fly on gooseberry leaf. Photo, by V. H. L. 1 See "The Pear Slug," in Circular No. 26, 2d Series, U. S. Depart- ment of Agriculture, Division of Entomology. APPENDIX TO CHAPTER II 41 APPENDIX TO CHAPTER II KEY TO THE PRINCIPAL FAMILIES OF LEPIDOPTERA a\. Antennae club-shaped at apex ; wings when at rest held vertical (Fig. 19) . .. «2- Antennae usually having the form of a bristle, spin- dle, or thread, often with a comb ; wings at rest held out flat (Fig. 23), or else folded over body like a gable roof (Fig. 25). bi. Hind wing usually with one or two dorsal veins [Macrolepidoptera, large-winged moths]. d. Antennae spin die- shaped or keeled, rarely club-shaped ; wings small ; dusk fliers. d\. Antennae prismatic . . . . . cZ2. Antennae not prismatic, but e\. attenuated at end, occasionally pectinate . . . - . /i. Clear winged (Sesiina). /2. Wings speckled, antennae much longer than head (Cossina) . /3. Antennae hardly longer than head (Hepialina). 62- club-shaped, occasionally pec- tinate . . . , ; C2. Antennae bristle- or thread-like ; wings mostly broad, night fliers. d\. Wings when at rest placed like a gable roof over body, or envelop- ing it ; proboscis well developed. e\. Subcosta of hind wing united with radius for a considerable dis- tance ; body hairy . . . e2. Subcosta of hind wing nearly or quite distinct from radius ; ab- domen ending conically . Papilionidce (Butterflies) Sphingidce (Hawk-moths) Xylotropidce, (Wood-borers) Zygcenidce (Zygenids) Arctiidce (Tiger-moths) Noctuidce (Owlet-moths) 42 ZOOLOGY d2. Wings as in di ; proboscis usually weak ; abdomen rounded at apex ; antennae pectinate . . . Bombycidce (Silk-worms) d3. Wings rest horizontally ; proboscis weak Geometridce (Measuring-worms) 61. Hind wing with three dorsal veins [Microlepi- doptera, small-winged moths]. Ci. Wings not divided or parted. di. Wings rest in gable fashion, with short fringe or none at all. e\. Anterior wings elongate-tri- angular ; palps extending be- yond head .... Pyralidce (Pyralidsl 62. Anterior wings much elongated, cambered ; antennae with thick basal segment ; palps slightly protruding . ....•'. . Tortricidje (Leaf-rollers) dz. Wings at rest, flat or enveloping the body ; the anterior wings with long fringe ; strongly developed palps - . Tineidce (Leaf-miners) C2. Wings divided or parted . . . . Pterophoridce (Plume-moths) KEY TO THE PRINCIPAL FAMILIES OF HYMEXOPTERA a\. Trochanter simple ; female with sting. 61. First segment of the hind leg more or less compressed, at least on inner side, and often thickly hirsute . • . ... ... . .' Apidce (Bees) 62- First segment of hind leg more or less cylin- drical, neither markedly broadened nor hairy. APPENDIX TO CHAPTER II 43 Ci. Anterior wings folded once lengthwise ; antennae usually clearly bent at an angle Vespidce (Wasps) C2- Anterior wings not folded lengthwise. d\. Abdomen appended or peduncu- late, oval or broadest anteriorly, gradually tapering posteriorly . Superfamily Fossoria (Digger and Mud Wasps) d2. Abdominal stalk formed of one or two knots or scale-like rings ; an- tennse flagellum-like . ; . Formicidce (Ants) «2. Trochanter of two segments ; female with ovi- positor. 61. Abdomen not sessile, but appended or pedun- culate ; anterior rings without lancet-cells ; hind wings with two root-cells . Superfamily Entomophaga (Parasitic and Gall-producing Hymenoptera) 62. Abdomen sessile (or continuous with thorax) ; anterior wing with lancet-cell ; hinder wing with three root-cells . . Superfamily Phytophaga (Plant-eating Hymenoptera) CHAPTER III THE BEETLE AND ITS ALLIES BEETLES (Coleoptera1) can be distinguished from other insects by the fact that the anterior pair of wings (elytra) are modified to form two horny shields, covering the pos- terior part of the body, while the posterior pair of wings are membranous. The mouth parts are formed for biting.2 During development, the beetles, like the Lepidoptera and Hymenoptera, undergo great changes of form. These changes may be observed in the potato-beetle. In this species the orange-colored eggs are deposited often in a very regular manner on the under side of the potato leaf. Here they develop for several days. In about a week, however, the young, reddish, black-spotted larva, or " grub," emerges. Like the adult beetle, it has three pairs of tho- racic legs. After feeding actively for two or three weeks, the larva descends into the ground, forms a naked yellow FIG. 41. — Larva of Lachnosterna, the June bug, at roots of aster. Photo, of living animals, nat. size, by V. H. L. s, sheath ; irrepbv, wing. 2 A key to some of the chief families of Coleoptera is given in the Appendix to this Chapter, page 58. 44 THE BEETLE AND ITS ALLIES 45 pupa, and emerges in about ten days as an imago. From two to four broods are produced during the year. The adult beetles hibernate in the ground, emerging and laying eggs the following spring. The larval habits of the different kinds of beetles are extremely varied, quite as varied as the habits of the adult. The details of these differences may be best considered when we take up the different kinds of beetles. The number of species of beetles which have been de- scribed is very great, probably over one hundred thousand. Of these, over ten thousand inhabit America, north of Mexico. Fortunately this vast number can be included within a relatively small number of families. Leaving the precise definition of these families to the table in the Appendix, we may here consider certain of the salient general characteristics. The running beetles include two principal families. The first of these is the tiger-beetles (Cicindelidse *), which are colored bright brown or green. They frequent sunny places, especially paths or sandy shores, and are extremely agile.2 The larvae are hunch-backed creatures, have a huge head armed with long jaws, and live in burrows, at .the entrances to which they lie in wait for their prey. The second family of the running beetles includes the ground-beetles (Carabidse3 in narrow sense). This family FIG. 42. — Three common species of Cicin- dela, the tiger-beetle. Left, red-copper bronze ; middle, brown, with yellow mark- ings; right, bright green, cream-colored markings. From Packard. 1 Derived from candela, candle. 3 /c<£/>a/3os, beetle. 46 ZOOLOGT is composed of about ten thousand species, of extremely varied form, size, and coloration. Most of them are of a shiny black color, usually with longitudinal ridges or rows of punctations on the elytra.1 They live on the ground, and during the daytime they are concealed underneath boards and stones, but at night they fly and climb trees and shrubs in search of other insects. They are most abundant near watercourses, and are sometimes found on the seashore. Some species emit ill-smelling fluids, often with a popping sound. These fluids serve to defend them from their enemies. Some species are vegetable feeders, for instance one species whose larva? are destructive in the South to young Indian corn. The next two families, Dytis- cidae2 and Gyrinidae,3 include beetles which are quite as de- structive to animal life of the water as the runners are to those of the land. The Dytiscidse are often large species, which have long, thread-like antennae. The Gyrinidse have short antennae and whirl around on the surface of the water, often in groups. Each eye is divided into an upper half, used for looking into the air, and a lower half, used for looking into the water. The larvae of both of these families have a long and spindle- shaped or flattened body and live in the water. 1 Fig. 43. 2 BiJTrjs, diver ; 5vriK6s, fitted for diving. 3 From 7u/o6s, circle ; because this beetle swims in a circle. FIG. 43. — Calosoma scrutator, the searcher, a ground-beetle. Nat. size. Photo, by W. H. C. P. THE BEETLE AND ITS ALLIES 47 Another family of aquatic beetles includes Hydrophilus 1 and its allies, which are less strictly carnivorous than the last two families. Their antennge are short and club-shaped, and their bodies are plumper than that of Dy tiscus, which is of about the same size and lives in similar places. The next family includes certain short-winged beetles (Staphylinidse 2), so called because the elytra cover only a small part of the abdomen (Fig. 44). These beetles (" rove -bee ties") are usu- ally black and of small size. They are very common under decaying or- ganic matter, stones, and other objects lying on the ground. They run swiftly. Some species mimic ants and wasps. Not only do they resemble these FIG. 44. — Anthopha- gus, a staphylinid. From Packard. FIG. 45. — A staphylinid elevating the abdomen. Photo, by W. H. C. P. Hymenoptera in the general form of the body, but also in the movements of the tip of the abdomen, which, when the >, water ; 0/\os, loving. 2 \tj'os, from 0-Ta0v\iJ, a cluster, is Aristotle's name for a certain insect. 48 ZOOLOGY animal is irritated, is raised as though to sting (Fig. 45). These beetles feed upon decaying animal and plant matter; consequently they are useful scavengers. Some species in- habit the nests of ants and of termites, but their relations with their hosts are unknown. The larvae are not unlike the adults, and inhabit similar situations. The carrion or sexton beetles (Silphi- dse1) are usually of medium or large size, and are either stout-bodied, with red spots on each elytron (Necro- phorus2), or very much flattened and FIG. 46. — Silpha amer- .,,,,. T -, , . /o., , T^. 4f*^ icana, a carrion bee- With thin-edged elytra (Silpha, 1 ig. 46). tie. From " standard The species of Necrophorus are power- Natural History." lul animals. When one or more pairs of these beetles discover a dead bird or small mammal on the ground, they dig out the earth from underneath and pile it upon the animal until eventually the car- cass is entirely buried. Then the female deposits her eggs upon the body, so that a rich supply of food is provided for the young larvae which hatch from the eggs. The members of the genus Silpha do not bury a carcass, but live and rear their young beneath it. While the families of beetles hitherto considered are in general useful to man by acting as scavengers or by destroying insects injurious to vegetation, we have now FIG. 47. — Anthrenus, the muse- um pest, a dermestid. Left, larva ; middle, pupa ; right, adult. From Packard. 7, an ill-smelling insect. 2 veicpfa, a dead body ; 0w, to bear. THE BEETLE AND ITS ALLIES 49 to consider a family, that of the Dermestidae,1 which is economically directly injurious in a variety of ways. The species of this family include small, oval, or elongated beetles with gray or brown markings, which are due to scales and can be rubbed off. The larvae are fuzzy, and are more injurious than the imagos. They feed on wool, leather, fur of all sorts, as well as on dried and salted meats. Our most destructive species have been imported from Europe. One of them is the carpet-beetle or "buf- falo-bug," which lives upon carpets and clothing. The museum pest is a closely related species which works sad havoc with insect collections, unless these are subjected several times a year to the poisonous fumes of carbon disulphide (Fig. 47). The stag beetles (Lucanidae2) have received their com- mon name from the resemblance of their long, often branched mandibles to the antlers of a stag. The plates of the club-shaped antenna cannot be brought compactly together, as in the next family. The adult beetles live on the sap of trees, and the larvae bore into the wood of the roots and trunk. The common large stag-beetle, which is often attracted into our houses by lamplight, is Lucanus dama. In the South the giant stag-beetle (Lucanus elephans) is found, with mandibles which, in the case of the male, are more than three-fourths the length of the body. Closely allied to the last is the great family of lamelli- corn3 beetles, in which the ends of the antennae bear flat, 1 Sepfj.rjvT'/is (5^/tyia, skin; &r0iw, to gnaw), a worm which destroys pelts. 2 From lucus, grove. 3 lamella, a small plate or leaf ; cornw, horn. B FIG. 48.— Dorcus, a stag - beetle. Nat. size. Photo, by W. H. C. P. 50 ZOOLOGY i closely applied plates. This family includes many very large insects. We can separate it into two groups, — the scavengers and the leaf-chafers. The scavenger larnellicorns, commonly known as tumble- bugs, live in the dung of horses and cows, which they form into balls and roll long distances (Fig. 49). The dung-rolling habit has long excited interest; indeed, among the Egyptians it was a source of superstition. So high ^f ^ 'JiH mm. was the veneration of this people for this their sacred beetle, that they reproduced it in their paint- ings and sculpture. The ball of dung is really intended for the dep- osition of an egg, and it is rolled by both males and females to a hole in the ground which has been dug in a safe place for its reception. The leaf-eating lamellicorns include the May-beetles or "June-bugs" (Laclmosterna1) which are attracted by lamplight at night. They enter with a busy humming sound, soon come in violent contact with the wall or a piece of furni- ture, and fall heavily to the floor. They feed at night upon the foliage of trees and shrubs. Another common species is the rose-bug,2 which bears the name Macro- dactylus 3 bubspinosus. It is destructive to the blossoms and young fruit of grapes, FIG. 49. — Copris, a tumble- bug^ Nat. size. Photo, by , sheep's wool ; vrtpvov, the chest. 2 Fig. 50. 3 /ia/c/)6s, large ; 5ci/rriAos, finger. FIG. 50. — Macro- dactylus, the rqse-bug. Nat. size. Photo, by W. H. C. P. THE BEETLE AND ITS ALLIES 51 roses, and other members of the plant family Rosaceae. The larvae of the May-beetles are the fat, whitish, bowed grubs which are often found in the spring in the soil where they have passed the winter. They are very destructive, for they feed on roots of grass, herbs, and shrubs (Fig. 41). Another family of beetles very destruc- tive to trees is that of the metallic wood- borers or Buprestidae.1 The adults are found upon flowers and the bark of trees, where their metallic colors glitter in the sunshine (Fig. 51). The larvae, which have relatively enormous heads, bore FlG' J ruftpes, a metallic beneath the bark of trees or into the wood. This family reaches its highest development in the tropics. Closely allied to the foregoing is the family of click beetles or Elateridae.2 These have the power, when placed on their backs, of leaping into the air by means of a special device on the under side of the animal (Fig. 52). The larvae, called " wire- worms " because of their round, hard bodies, live under the bark .of trees and in rotten wood or upon vegeta- tion in the ground. They are most de- structive to germinating grain, especially FIG. 52.— One of the maize. It requires several years for them to mature. The fireflies (Lampyridae3) make up wood-borer. From "Standard Natural History." click beetles. Nat. size. Photo, by W. H. C. P. s, among the ancients a poisonous beetle, living in grass by swallowing which oxen (/Sous) swell out (TT/^W) . , driver. 8 Xd/*7ra>, to shine ; otpd, tail. 52 ZOOLOGY another and a well-known family. They are distinguished by soft wing-like elytra and by the great expanse of the thoracic shield, which partly or wholly covers the head. Certain non- luminous species live on flowers, especially the golden-rod ; the lumi- i FIG. 53. — Photuris, a firefly. a, larva ; b, adult. The lines to the left of figures represent actual lengths of animals. From Packard. nous species are noctur- nal. The light-giving or- gan lies in the abdomen. The larvae also are lumi- nous and are known as glow-worms (Fig. 53). A family of consider- able economic import- ance is that of the Tene- brionidae, so called from the principal genus Tenebrio,1 the larva of which, known as the meal- worm, occurs in flour and cereals and looks much like a wire-worm.2 The adult beetle is black and about one-half an inch long (Fig. 54). The family is not abundant in the northeastern part of the United States. Several kinds of adult beetles be found under the bark of can FTG. 54. — Tenebrio, the meal- worm. Left, larva ; right, adult. From Leunis. 1 Miller, because it lives in flour. 2 These larvse are reared by bird-fanciers for bird food, and may be obtained in bird stores. THE BEETLE AND ITS ALLIES 53 trees, but these are mostly carnivorous and are seeking their prey there. The minute bark-borers or engraver beetles (Scolytidse1), however, feed on the innermost layer of bark. As they eat in lines, a pattern is formed which is characteristic for each species. Along these lines, niches are made in which eggs are laid and larvae hatch. The borings are injurious to the trees, often causing their death. Herbaceous plants also are infested by certain spe- cies. An example is the destructive Pine Borer (Fig. 55), which is common throughout the United States and Canada. One of the most injurious of all the families of beetles is that of the weevils (Cur- culionidse2). These beetles are small, and their heads are drawn out into a long snout by which they bore holes in plant tissue to receive their eggs (Fig. 56). The dull colors of the beetles render them in- conspicuous to insect-feeding birds. The number of species is reckoned at over ten thousand, and the family is of world- wide distribution, its dispersion having been aided by com- merce. Grain-weevils are great pests in stored wheat, rice, or maize. They also oviposit in the planted seeds. Buds are attacked, and nuts, stone fruit, and fleshy fruits are made " wormy " by them. Extremely destructive also is the great family of long- FIG. 55. — Den- droctonus, an engraver bee- tle. Magnified 2.5 times. From "Standard Nat- ural History." FIG. 56. — Balani- nus, a weevil, of brown color. From Packard. 1 From (r/coXi57rTw, to mutilate. 2 curculio, a grain-weevil. 54 ZOOLOGY horned beetles, "buck-beetles," (or Cerambycidse1), of which about six hundred species are known in North America alone. The an- tennae and legs of these beetles are very long.2 The larvae bore into even the hardest woods, and live in the wood for two or three years. Timber and shade trees are thus greatly dam- aged. A favorite collect- ing ground for Ceramby- cidae is the golden -rod, where the black, yellow- banded locust borer, Cyllene robince (Fig. 59), is pretty sure to be found. Still another destructive family is that of the leaf-eating beetles, — the Chrysomelidae,3 to which the potato-beetle belongs. These beetles are thick and round in shape. They lay their eggs upon the leaves of plants. The larvae feed on the leaves or burrow in the stem. Usually the larva is conspicu- ously colored and exposed, and relies for protection upon its dis- agreeable odor and taste. The most destructive species to agri- culture in the northern United FIG. 57. — Prionus latlcollis, a long- horn. Black. Nat. size. Photo, by W.H.C.P. FIG. 58. — Orthosoma bnui- neum, the straight -bodied Prionid. Brown color. Nat. size. Photo, by W. H. C. P. ;, a beetle with long horns. 2 Figs. 57 and 58. 3 chrysomela, gold beetle, from xPVfffa> gold, and /x^Xoi/, apple. THE BEETLE AND ITS ALLIES 55 States is the ten-lined Colorado potato-beetle, Doryphora1 decemlineata. Until about 1859 this species fed upon the sand-bur {Solanum .ro stratum), at the eastern base of the Rocky Mountains and south into Mexico. With the advent of settlers and the plant- ing of the cultivated potato {Solanum tuberosum, a native of Mexico), this more thrifty, cultivated species was adopted as its food-plant, and the potato-beetle began its eastern migration. It spread slowly at first, but within fifteen years had reached the Atlantic coast. The little red, yellow, and black asparagus-beetle^ the yellow, black-striped cucumber and melon beetle, the tortoise-beetle, whose broad, iridescent, translucent elytra are conspicuous on the leaves of the morning-glory, nettle, and other plants, all belong to this family. So long has become our list of destructive beetles that it is with satisfaction that we turn at the end to a family which is almost wholly beneficial to the vegetable kingdom, as well as to most vegetable-feeders, includ- ing man. This is the ladybird family, FIG. 59. — Cyliene Coccinellidae. These beetles are preda- ™Un^ ,the ^cust x borer, found on ceous, both in the larval and adult stages, the golden - rod. feeding upon small insects and insect eggs ^hpt0' by w> H'' (Figs. 60 and 61). They are especially active in freeing plants from scale-insects and plant-lice. So rapidly do the latter multiply that were it not for the voracious larvse of the ladybird most plants would be 1 5o/>u06/>os, spear-bearing. 56 ZOOLOGY FIG. Anatisocel- lata. Adult. Nat. size. Photo, by V.H.L. destroyed in a single season. The larvae of the ladybirds are dark, spotted, and hirsute. One of the commonest of four eastern ladybirds is a red- backed, two-spotted one (Adalia bipunctata). The food of beetles is, as we have seen, extremely varied, more varied, indeed, than that of FIG. CO. —Pupa of , , -> £ . -, Anatisocellataon anJ other or, to like. 3 Of the horse. 66 ZOOLOGY intestine of the horse they get abundant food, and there they develop. The larvae of another species, " the ox- warble " or "grubs," are taken into the mouth of cattle, and live for a time in the oesophagus. Then they bore their way through the walls of this tube, and travel on until they make their way out through the skin to the surface. Another injurious species is the sheep bot-fly, whose larvae cause " staggers " in sheep. The Syrphidae,1 like the bot-flies, mimic honey-bees, bumblebees, and wasps.2 The adults feed on the pollen and nectar of flowers, and even imitate the humming of the bee. The larvae of some forms feed upon plant-lice ; others, upon decaying vegetable matter. They may occupy the nests of various stinging Hymenoptera. The larvae of some species are known as rat-tailed maggots on account 1 of their having a characteristic append- l^jjjf age. These are sometimes found floating jHBMp** iii foul water or even in salt water. The robber-flies (Asilidae3) are usually jlHwl °f large size, have a short head, prominent eyes, legs covered with stiff hairs, and abdomen either long and slender (Fig. - — — 1 65), or stout. These flies attack and de- vour other flies and even insects much larger than themselves, such as bumble- bees and dragon-flies. The horse-flies (Tabanidse4) include the large mourning horse-fly, Tabanus astratus, which is of a uniform black color, the white-lined Tabanus, T. lineola (Fig. 66), and the smaller golden-headed horse and ox flies with banded 1 cru/>06s or fftpos, a small winged insect. 2 Fig. 64. 8 From asilus, a gadfly. 4 From tabanus, the gadfly of Pliny. FIG. 65.— Robber- fly. Nat. size. Photo, by W. H. C. P. THE FLY AND ITS ALLIES 67 wings (Fig. 67). Only the female sucks blood, while the male feeds in flowers. They are powerful and rapid fliers. The larvae are carnivorous and live in the earth or water. FIG. GG. — Tabanux llmola, white- lined horse-fly. X 1.2. Photo, by W. H. C. P. FIG. 67. — Chrysops, banded horse- fly. X 1.5. Photo, by W. H. C. P. The black-flies (Simuliidse r) are representatives of the long-horned flies (Nematocera). They are familiar pests in the forests of our Northern country. The females, which alone suck blood, occur in such num- bers and are so active that they render certain places almost uninhabitable to man. Their bite often produces wide- spreading and painful inflammation, accompanied by swelling (Fig. 68). The larvae are aquatic. The Southern black-fly or " buffalo gnat " sometimes causes the death of domestic animals. The gall-gnats (Cecidomyidse 2) are minute flies which lay eggs on plants, their way into the plant tissue, and cause the further de- velopment of the tissue to be abnormal, so that excrescences FIG. G8.— Simulium, the black-fly. En- larged. From Packard. The larvae make 1 From simul, together ; or simultas, a hostile encounter. 2 s, gall-apple ; /tvta, fly. 68 ZOOLOGY or galls are produced. The galls are formed only in grow- ing tissue such as the tips of branches, buds of flowers or growing leaves, and are less striking on the whole than the galls of Hemiptera (Fig. 69). A certain kind of gall-fly, called Hessian-fly (Fig. 70), is extremely injurious to wheat FIG. 69. — Plant galls produced by Hemiptera and Diptera. 1. Pine-apple gall on twigs of the spruce fir produced by the spruce-gall Aphis (C'herines abretis, one of the Hemiptera). 2. Covering gall on the petiole of the pyra- midal poplar (Populus pyramidalis) , produced by Pemphigus bursarius, one of the Hemiptera. 3. Covering galls on an ash leaf (Fraxinus excelsior) , produced by Diplosis botularia (Diptera). 4. Covering gall on Pistacia (Pistacia lentiscus), produced by Pemphigus cornicularius. 5. Solid galls on the cortex of Duvana lonyifolia, produced by Cecidoses eremite (Hemip- tera) . fi. Longitudinal section of one of these galls. 7. Capsule galls on the leaf of the turkey oak ( Quercus cerris, Hemiptera) , produced by Cecidomyia cerris. 8. One of these galls cut through, with the operculum still firmly attached. 9. The same, with the operculum falling away ; X 3. The remain- ing figures natural size. From Kerner, " Pflanzen Leben." THE FLY AND ITS ALLIES 69 FIG. 70. — Cecidomyia, theHessian- tfy. (/, larva; b, pupa. From the " Standard Natural History." because it infests wheat seedlings and so weakens them that they produce no grain. Other minute gnats or midges are destructive to clover in the United States, either by binding the leaves together and sucking the sap of the destroying the plant or by young seed. The mosquitoes, or Culicidse,1 are so well known that it is hardly necessary to describe them. They can always be identified by the feathery an- tennse, by the presence of a fringe of hairs on the hind margin of the wing, and by the fact that the marginal vein runs all around the periphery of the wing. The larvse are usually aquatic, but some species which are abun- dant on our Western arid plains must breed in the earth. The eggs of the aquatic species are laid in a boat-shaped mass, which floats on the surface of the water. The larvae escape abdomen with the two oar-like swim- from the lower ends of the ming appendages, dorsal view. After drawing of E. Burgess. FIG. 71. — Culex, the mosquito. A, larva; c, its respiratory tube. B, pupa ; cl, the respiratory tubes; a, the end of the egg-cases, and are known as "wigglers.'" The larvse rest vertically near the surface of the water, head downward, with the tail end of the body at the surface of the water, 1 Culex was Pliny's name for the fly. 70 ZOOLOGY since respiration takes place at that end (Fig. 71, A, dyw, to eat. 6 Flea. 7 Irritating. 72 ZOOLOGY Diptera affect man directly in very diverse ways. House-flies, black-flies, mosquitoes, and fleas are a positive source of discomfort, and often of disease. Thus there is a minute round worm, Filaria l hominis? allied to the vinegar eel, which thrives as a parasite in the blood-vessels of men living in the tropics. The existence of this parasite, it is believed, depends upon the mosquito. The embryos are found in the surface circulation only at night, during which time man is most defenceless toward the mosquito. The embryos of the Filaria which have been sucked out of the blood by the mosquito develop in its alimentary tract, later they are deposited in stagnant water with the eggs of the mosquito, and reach man's body again if the water be drunk by him. It is a current scientific belief that house-flies, whose larval stages are often spent in filth, which also the egg- laying females visit, are an important agent in the distribu- tion of disease. At least the suspicion is strong enough to justify all care taken to exclude flies from contact with food. Indirectly Diptera are injurious to man by attacking domestic animals and cultivated plants. Thus the tsetse- fly is a menace to the commerce of a large part of a conti- nent. The horse-fly, the horn-fly, which worries cattle, the buffalo-gnat, which worries or even kills domestic animals, and the dangerous bot-fly, are all causes of great loss to industry. Also we have seen that the larvae of some flies infest vegetables, — such as cabbage, radish, cauliflower, onion, — as well as various fruits, and cause great damage. The gall-gnats destroy clover and its seed ; and, worst of all, the Hessian-fly infests wheat and Indian corn. This last-named scourge, so called because of a tradition that it 1 filum, thread. 2 Of man. THE FLY AND ITS ALLIES 73 was imported in the straw bedding of the troop-ships which brought over the Hessian mercenaries in 1775, has spread, within a century, over the eastern half of the United States, and has at various times injured the wheat crop to the value of millions of dollars. The larvae of certain Muscidse, especially the genus Chlorops,1 attack, in Europe, the stems, leaves, and ears of wheat, rye, and barley, and cause in some years great destruction, especially in Scan- dinavia. Over against the injury wrought by the Diptera may be placed certain benefits bestowed by them. In the first rank come certain species which prey upon injurious insects, either in the larval or adult stage. The robber-flies prey on the Diptera, Hymenoptera, and certain beetles, but they are not careful to choose alone injurious species. The larvae of the Syrphidse prey on the injurious plant-lice; those of horse-flies are carnivorous, and feed on insect larvse. The larvse of certain small flies are internal parasites of bugs, beetles, and other (mostly injurious) insects ; while those of various other Diptera are useful in acting as scav- engers, — mosquito larvse, for example, serve in this way. The carrion-fly devours putrid animal substances, which might otherwise be a source of discomfort or disease. The insects which feed on decaying vegetable matter are also not to-be despised. Finally, the larvse of some crane-flies, robber-flies, and ' Syrphidse, by boring into rotten wood, help in the work of forming forest mould. The Diptera, like almost every other insect group, has its economically injurious and beneficial species, and it is impossible to say whether mankind would be better or worse off were the group to be exterminated. green ; oty, eye. CHAPTER V LITHOBIUS AND ITS ALLIES LITHOBIUS is a representative of the group Myriapoda,1 which are air-breathing, wingless Arthropods, closely allied to insects.2 In the body only two regions, head and trunk, can be distinguished ; the head bears one pair of antennae, a pair of jaws, and one or two pairs of maxillae. Every segment bears legs. Myriapods differ from insects, then, in that they have no legless abdomen. Myriapods fall into two principal groups, — Chilopoda 3 and Diplopoda.4 The chilopods, or centipedes, to which group Lithobius belongs, are active and ferocious rnyriapods. They are especially abundant in tropical countries, but thrive also in elevated, cold situations, and at least one species inhabits the caves of North America. All are terrestrial, and live in damp and dark places, especially under stones and bark, within or under decaying wood, among barn-yard refuse, in loose soil, and under fallen leaves. Chilopods feed upon living insects, mollusks, and worms, and may be useful to agriculture through the destruction of injurious s, very many ; TTO^S, foot. 2 Keys to the principal families of the Myriapoda, and to the commoner species of Lithobius, will be found at the end of the Chapter, page 78. 3 More correctly Cheilopoda, from •^el\oby genera include a few animals about 1 millimetre long, found on the moist loam of woods. They are intermediate between chilopods and diplopods, inasmuch as they have only one pair of legs 1 7roXi/5e0-/ios : TroAtfs, much ; 5eo>i6s, band. 2 Traupos, small ; TTO^S, foot. 78 ZOOLOGY to a segment and only one pair of maxillre. P. huxleyi occurs both in Europe and in the United States (vicinity of Boston and Philadelphia). Scolopendrella 1 is a small, white species, having very large antennae and a pair of backward-directed stylets. The mouth parts are very much like those of the lowest insects, so that Scolopendrella bridges the gap between myriapods and true insects. APPENDIX TO CHAPTER V KEY TO THE PRINCIPAL FAMILIES OF THE MYRIAPODA a\. Not more than 1 pair of feet to the segment ; much segmented antennae ; 2 pairs of maxillae [Chilopoda]. 61. With facetted eyes ; 8 dorsal plates ; long legs . ,.-•-.. • ' -. • • bo. No facetted eyes, but single or aggregated simple eyes ; 15 or more dorsal plates. ci. 15 pairs of legs ; antennae at least £ as long as body ; body usually with more than 20 segments Ci. More than 21 pairs of legs. d\. 21 to 23 pairs of legs ; antennae more than 14-jointed d-2. Never less than 30 pairs of legs ; antennae 14-jointed . • . . Most of the segments with 2 pairs of legs ; an- tennae with 5 to 8 segments ; 1 pair of maxillae [Diplopoda]. 61. Anus in penultimate segment ; body covered with bunches of hairs . . " . . Scutigeridce (Ex. Scutigera) LithobiidcB (Ex. Lithobius) Scolopendridce (Ex. Scolopendra) Greophilidce (Ex. Geophilus) PolyxeniddB 1 Diminutive of Scolopendra. APPENDIX TO CHAPTER V 79 Anus in ultimate segment; body without bunches of hairs. Ci. Mandibles not rudimentary ; mouth parts not suctorial. d\. Segments 30 or more. e\. Anal segment produced into a spine .... Julidce (Ex. Julus) 62- Anal segments produced into 2 slender papillae, or uni- dentate .... Craspedosomidm dz. Segments 19 or 20 . . . Polydesmidce (Ex. Polydesmus) C2. Mandibles rudimentary, mouth parts reduced .- Polyzoniidce KEY TO COMMONER SPECIES OF THE GENUS LITHOBIUS ai. Posterior angles of none of dorsal plates pro- duced ; pores on coxae uniseriate. b\. A nal feet armed with 1 spine ; posterior coxae unarmed ; spines of first pair of feet, 2, 2, 2-2, 3, 2 (Central States) . . . bilabiatus 62. Anal feet armed with 3 spines ; coxae with indistinct spine ; spines of first pair feet, 2, 3, 2 (Central States) . . . ' _.: cardinalis «2- Posterior angle of the 9, 11, 13 dorsal plates pro- duced; antennae, 33-43 joints (eastern U.S.) forficatus «3. Posterior angle of the 7, 9, 11, 13 dorsal plates produced ; 31-38 joints of antennas (southern U.S.) . . . . , . . . spinipes «4. Posterior angle of the 6, 7, 9, 11, 13 dorsal plates produced ; joints of antennae, 14-23 (eastern U.S.) . « . . . . . multidentatus CHAPTER VI THE SPIDER AND ITS ALLIES SPIDERS constitute a well-defined group called Araneina,1 characterized by an unsegmented cephalothorax and abdo- men, of which the latter is stalked, and bears spinning tubercles or spinnerets upon its hinder end. Antennae are absent. The first pair of mouth appendages are called chelicerse and end in claws, at whose apices the poison- glands open to the exterior. The second pair of mouth parts, called pedipulps, are long, and seem to take the place of antennae. Near the stalk of the abdomen on the ventral side is a pair of slits which open into two lung sacks (hence Dipneumones). In a few spiders there is a second pair of slits ; these spiders have four lung sacs (hence Tetrapneumones).2 The best known of our spiders are the orb web-spinning garden spiders, belonging chiefly to the genera Epiera3 or Argiope 4 and the house cobweb spinning spider Theridium.5 Argiope spins webs of very geometric form between stems of weeds, branches of shrubs, or along fences in our meadows.6 Its web belongs to the full-orb type in 1 aranea, spider. 2 A key to the seven subdivisions of the Araneina will be found at the end of this Chapter, page 95. 3 efjureipos, skilful, experienced. 4 Name of a nymph. 6 0rjpl5iov, a little wild animal. 6 Fig. 78. 80 THE SPIDER AND ITS ALLIES 81 contrast to the condition in other orb-spinners, in which a sector of the circle is omitted or in which a sector only is formed. At the centre of the web of Argiope there is an oval, closely woven shield of silk. The spider, when at rest, is usually found upon or under this shield. Another frequent character of the web is a zigzag ribbon,, extending FIG. 78. — Web of Argiope, placed horizontally over a fish-way. Photo, by W. H. C. P. downward from the central shield, and sometimes upward also, and attached to two or more radii. This zigzag, which is doubtless the " winding stair " referred to in the rhyme, " The Spider and the Fly," is formed, as Fig. 79 shows, by preventing the fusion of the strands as they emerge from the spinnerets. 82 ZOOLOGY The genus Theridium and its allied genera constitute the most extensive family found in the United States. The spiders belonging to the family are small, with relatively large, rounded abdomens. They have eight eyes, arranged in the manner shown in the diagram, Fig. 80. Their webs show no attempt at geometric arrangement, such as is seen in the web of Argiope and other orb-weavers, but the threads cross in every direction, forming a sort of intricate trestle- work. The species Theridium tepidariorum is the common little cobweb-spinner of our houses and barns ; it also spins about fences. Its color varies from a livid white to a livid brown or plumbeous color. In the south this species FHJ. 79. — Argiope spinning the "winding . stair." The numbers 1, 2, 3, 4, indicate IS much preyed upon points successively formed in the order of these numerals. From McCook. ^y mud-daubing wasps J P (Sphex J), which put twenty to thirty of them in each cell of the nest as food for the young. Probably this enemy is one of the causes that has driven this species to the homes of man. Food. — Both Argiope and Theridium feed upon insects. Flies, bees, grasshoppers, etc., are caught in the web and 1 if]Z, wasp. THE SPIDER AND ITS ALLIES 83 bound up, either for immediate or future consumption. A few authentic instances have been recorded of the capture of mice by ordinary spiders, and some tropical 0 o o o spiders are said to capture occasionally small 0 0 birds within their Avebs. All spiders eat FIG. so. — Dia- , ,. . , . , gram of posi- voraciously, and ordinarily drink a great thmof eyesm deal of water; yet they may survive, in Theridium. •J J The four cen- the absence of food and water, for many trai eyes are months. the larsest- Distribution. — Argiope occurs over all of North America. A. cophinaria, the basket Argiope, is the large black and yellow spider well known to all frequenters of fields. It occurs from Massachusetts to Texas, and west to the Pacific coast. A. argentata, distinguished by the serrated form of the abdomen, is found in the Southern States, the West Indies, and northern South America. Theridium occurs all over the world. T. tepidariorum is found, outside of the United States, in South America, Europe, and Australia. Twelve other species of this genus are found in New England alone. Some of these spin webs in trees or bushes, others in stone walls or among rocks. Spinning Habits. — Spiders spin for a variety of purposes. Cocoons are made of silk, for the protection of eggs ; under- ground nests, like that of the trap-door spider, are lined with silk ; and, especially, nets are made of it to ensnare insects. The silky threads may serve also to suspend the spider while it drops from a tree, or they may, by their friction with the air, serve to suspend certain spiders in aerial migrations.1 This latter use is especially noteworthy. 1 The ballooning habit of spiders has been noticed since early times, but it was formerly misinterpreted. Thus Pliny speaks of wool being rained. The poet Spenser wrote : — 84 ZOOLOGY A small spider, when desirous of taking flight, climbs up some high object, such as a fence post, elevates the spin- nerets, and spins loose silk into the air (Fig. 81). After enough of it has been thus formed, the spider lets go, and is supported by the currents in the air while it is wafted great distances. Thus Darwin, on his voyage in the Beagle, saw cobwebs bearing up spiders floating in the air over his vessel more than sixty miles from shore. The method of spinning deserves careful attention. The spinning-organs consist of a set of glands lying in the hinder part of the abdomen, and opening to the exterior through a number — - often several hundred — of spin- ning "spools." These spools are the modified mouths of glands, and are grouped upon and between tubercles called spinnerets. The secretions of the glands, as they are poured out into the air, fuse together and harden into a thread. The thickness of the thread is determined by the number of glands secreting together. " More subtle web Arachne cannot spin ; Nor the fine nets, which oft we woven see, Of scorched dew, do not in th' ayre more lightly flee." Thompson writes : — " How still the breeze ! save what the filmy threads Of dew evaporate brushes from the plain." THE SPIDEE AND ITS ALLIES 85 Classification. — Spiders are separated, according as they spin webs or do not do so, into two main groups, sedentary and wandering spiders. The sedentary spiders are sub- divided into four sub-orders, which we shall consider in turn : — FIG. 82. — Mygale, a Tunnel-weaver, allied to the " trap-door spider." Nat. size. From Emerton. 1. Tunnel-weavers (Temtelariee l) . These spiders make tubes in the earth, and line them with silk. The repre- sentatives of this group in the Southwestern States are 1 terra, earth ; tela, tissue or web. 86 ZOOLOGY FS FS commonly known as trap-door spiders. The lid of the nest is covered with hardened dirt, and when closed, looks exactly like the ground around it. Some of these spiders gain a great size and capture birds (Fig. 82). 2. Orb-weavers (Orbite- larise 1). These, which are typically represented by Argiope, are well known ; yet few persons have studied the almost mathematical precision with which the webs are built. FIG. 83. -Diagram on nomencla- Foundation lines (Fig. 83) tare of parts of an orb-web. FS, of UllUSUal strength are tirst foundation space ; SS, spiral , . , , ,. , , . , space; OS, central space ; FZ, laid down' to ioi>m the penpll- freezone; NZ, notched zone; H, eiy or frame of the Web. Then centre. From McCook. ,.. . radii are spun from a central little ball of floss to the frame. The radii are, often at least, laid down alternately on opposite sides of the centre. The number of radii formed by a species of spider is not perfectly constant, but varies within limits. It would be an interesting occupation to sketch a number of webs of Argiope showing the variations in the number of radii and the other details of form. After the radii are placed, the spiral lines are laid down. In the completed web four regions are distinguishable, as follows, passing from the centre outward : (1) the notched zone, consist- ing of four to eight turns of a spiral at the centre ; (2) the free zone in which no spiral is laid down ; (3) the spiral space, the main part of the spiral framework ; (4) the 1 orbis, circle ; tela, web. THE SPIDER AND ITS ALLIES 87 foundation space, without the spiral lines, and at the outer margin of the web. No study is more interesting than that of the details of construction of these parts of the spider web, while they are being made out of doors or in large glass jars. FIG. 8-1. — Orb-web of Epeira. a, first spiral line ; b, second spiral line ; c, line to nest. From Emerton. 3. Line- weavers (Retitelarise1). — Of this group The- ridium is a type. The web consists of a fine irregular mesh with strands running above and below in various direc- tions.2 The spider stands below the main part of the net, back downward. 1 rete, net ; tela, web. 2 Fig. 85. 88 ZOOLOGY 4. Tube- weavers (Tubitelaricti 1). -- Here belong the spiders that spin webs in the grass, which are so conspicuous in the morning when laden with dew (Fig. 86). At one side of the web a tube leads down among the grass stems. At the opening of this tube the spider stands ready to FIG. 85. — Web of Theridium, a " cobweb." From Emerton. dart out after prey, or to retreat as occasion demands (Fig. 87). The wandering spiders do not spin webs of any kind. They are classified into three groups as follows : — 1 tubus, tube ; tela^ web. THE SPIDER AND ITS ALLIES 89 (1) Crab spiders (Laterigradse *) are so called because they run sideways. They make nests by fastening together leaves by threads of silk. Their young are reared in these nests, and watched over by the mother (Fig. 88). (2) Running spiders (Citigradse2). — These are for the most part large and powerful species which wander over FIG. 86. — Web of a tube-weaver; looking down upon the web, which is in a corner between two vertical walls. The tube is in the angle. Photo, by W. H. C. P. fields or along watercourses in search of prey. Our Northern species belong chiefly to the genus Lycosa 3 (Fig. 89). They live in holes in the ground, making a ring of silk at the orifice. The female carries her eggs about in a special cocoon attached to the end of the abdomen. The 1 latus, side ; gradus, locomotion. 3 Xikos, wolf. 2 citus, rapid, + gradi 90 ZOOLOGY FIG. 87. — Agalena, the common grass spider. Nat. size. Photo, by W. H. C. P. young are borne on the back of the mother. The great size, black color, and hairiness of some of these spiders have given them an apparently unjustified reputation of being very poison- ous. Naturalists who have al- lowed these spiders to bite the hand report that the bite is rarely more poisonous than that of the mosquito. (3) Jumping spiders (Salti- gradse *). — This family includes many familiar, active species of high intelligence. Some of these of grayish color live in houses, and are recognized as members of this family by their half-running, half- jumping gait (Fig. 90). The cocoon is attached to some object and enclosed in a sort of tent, in which the mother also lives to guard the young. The economic impor- tance of spider webs is con- siderable. First of all, they are of the greatest importance in capturing many destructive insects, such as flies, mosquitoes, and moths. Another use 1 saltus, jumping, + gradus. 0 o o ° 0 o o ° FIG. 88. — Thotnisus, a crab spider. Dia- gram showing arrangement of eyes at bottom of figure. From Emerton. THE SPIDER AND ITS ALLIES 91 to which they have been put is in making silk cloth. The silk of the spider is smoother and glossier than that of the silk-worm, but it is much harder to collect in quantity. A spool is passed against the spinnerets of an individual spider and slowly revolved, winding the silk upon it. The difficulty comes in rearing the spiders, for they are extremely voracious and if the supply of flies is insufficient FIG. 89. — Lycosa,a running spider. FIG. (JO. — Attus, a jumping spider. Ocelli formula below. From Emer- From Emerton. ton. they attack and devour one another. Consequently they must be kept isolated and fed individually, and yet yield in the end only an ounce or so (about 30 grammes) of silk. Other uses of spiders' silk are : in the construction of cross-hairs in telescopes, and in medicine as a narcotic in case of fevers, — a temporary fad. Poisonous Spiders. — Spiders are feared by many people from a belief that they are very poisonous, even fatally so. Spiders have, indeed, biting jaws provided with poison- 92 ZOOLOGY glands, and their bite is often fatal to insects, and even to small birds and mammals. But most spiders cannot spread the chelicerse sufficiently to make a bite in the human skin, and even the largest forms seem to inflict but a slight wound, scarcely ever greater than that of a mosquito. The stories of the severe effects of the bite of the Taran- tula, one of the Lycosidae, are entirely fabulous. Spiders show a marked sexual dimorphism. Particularly among the orb-weavers the males are much smaller than the females of the same species, but the legs of the male are relatively the longer and stronger. The male is usually shorter lived than the female, for the latter has often to watch the egg-cocoons, or carry them about with her until the young hatch out. The male also builds less perfect webs than the female. The relation existing between mated pairs is often peculiar. The male is frequently killed and eaten by the female; but if the male can over- come the female, she may fall his victim. Among wander- ing spiders there is often a selection by the female from among several rivals, which engage in severe battles with each other. Allies of the spider must be briefly mentioned. The spider belongs to the class Arachnoidea,1 characterized as follows: Air-breathing, wingless arthropods, whose head and thorax are usually united to form a cephalothorax, which bears two pairs of jaws and four pairs of legs ; the ab- domen, which is not always separated from the cephalo- thorax, possesses no legs. The principal subdivisions of the Arachnoidea are as follows : — The Arthrogastra,2 including the scorpions and their allies, are characterized by the fact that the abdomen is , spider ; elSos, form. 2 dpdpov, joint ; yaarr^p, abdomen. THE SPIDER AND ITS ALLIES 93 segmented and intimately joined with the cephalothorax.1 Here belong the true scorpions, in which the posterior six segments of the abdomen are much smaller in diameter than the seven anterior segments, and form a sort of tail (post-abdomen). Nearly twenty species of scor- pions occur in the warmer parts of North America. Centrums in- famatus ranges from the southern Atlantic States, through Texas, and north into southern Kan- sas. The tip of the tail bears a sting, which con- nects with a poison -sac. The largest scorpions of the tropical countries are the most dangerous, but the wounds even of these are rarely fatal. The Phalangina,2 the extremely common "Daddy-long-legs," or harvest-men, in which the legs are very long, FlG 9i._Buthus, a European scorpion. and the abdomen short Dorsal view. MX., maxillary; Cephth., i • i Ta\dyyiov, a spider, especially a poisonous species. 94 ZOOLOGY FIG. 92. — Liobunum dorsatum, one of the harvestmen. The long legs are apt to be thrown off in handling the living animal. The second left leg is accordingly absent in this specimen. Nat. size. Photo, by W. H. C. P. FIG. 93. — Psoroptes, the sheep scab, female. IJight figure, dorsal view ; left figure, ventral. Much enlarged. After Salmon, Bulletin 21, Bureau Animal Industry. THE SPJTtE-R ANX> ITS ALLIES 95 man. Liobunum dorsatum is a common grayisli species with a darker dorsal band, which emits a clear fluid when handled (Fig. 92). The Areneina, or spiders, already considered. The Acarina,1 or mites and ticks, in which, as in spiders, the abdomen is unsegmented, but is fused with the cephalo- thorax. Mites have typically a round body. They exhibit great diversity of form and habits. All are terrestrial, excepting one group of aquatic mites, and are often of a bright red color (Atax). The free-living species prey on smaller animals, as well as dead organic substances. Others are parasitic in animals or plants, living in fur or feathers,2 and even jjne " ~ a sea- penetrating into the skin, as the small red - spider, x 1.5. 44 jigger" or " chigger " of our Southern fc^'aSS States does. Finally, there lives in the sea an aberrant family of spiders which crawl on the sea-bottom or over hydroids, and thus have forsaken a terrestrial life for a completely aquatic one (Fig. 94). APPENDIX TO CHAPTER VI KEY TO THE SEVEN SUBORDERS OF THE ARANEINA «i. With 4 slits into lung sac [Tetrapneumones]. Che- lifer claw directed downward ; 8 closely grouped eyes .... . .. . . Territelarne (Tunnel-weavers) «-2. 2 slits into lung sac [Dipneum ones]. Chelifer claw directed inward. , mite. 2 rig. 93. 96 ZOOLOGY Eyes in 2 transverse rows ; most species spin webs [Sedentariae]. Ci. Legs not spread flat out. di. Spinnerets short and inclined together, and on under side of abdomen, which is usually round. e\. Anterior row of eyes near margin of head . . . . 62. Anterior row of eyes remote from margin of head .... Orbitelarm (Orb-weavers) Betitelarios (Line-weavers) d\. Spinnerets at end of abdomen, which is elongated Tubitelarias (Tube-weavers) cj . Legs spread flat out ..... Laterigradce (Crab spiders) Eyes in 3 transverse rows ; spin no webs, but hunt prey [Vagabundse]. GI. Anterior eyes smallest ..... Citigradce (Running spiders) c2. The anterior eyes largest . . . Saltigradas (Jumping spiders) CHAPTER VII THE CRAYFISH AND ITS ALLIES THE crayfish belongs to the class of Crustacea, since it breathes by means of gills, possesses two pairs of antennae, a pair of mandibles bearing palps, and a pair of append- ages on all body segments excepting the last. The Crustacea are divided into two subclasses, — Entomostraca, of which Daphnia is an example, and Malacostraca, to which the crayfish belongs. All the Malacostraca 1 have 19 pairs of appendages.2 The crayfish,3 which is closely related to the marine lobster,4 is an inhabitant of fresh-water lakes, rivers, and pools. It thrives in diverse surroundings; for some species prefer cool mountain streams and others muddy pools, while certain species, both in Europe and America, are found in brackish as well as fresh water. Indeed, the European Astacus fluviatilus is said to be frequently s, soft ; & QQ. * Kapts, a small marine crustacean. THE CRAYFISH AND ITS ALLIES 105 along our coast, and even penetrate into rivers. Two river shrimps 1 are found in the United States east of the Missis- sippi River. These Crustacea are able to maintain their enormous numbers only by virtue of their great repro- ductive capacity, necessitated by the circumstance that they furnish almost the entire food supply for many kinds of fishes and other foes. Even in the principal shrimping grounds of the United States — such as San Francisco and FIG. 97. — Gebia affinis, right side. Two-thirds natural size. ' Photo, by W. H. C. P. New Orleans — there is said to be no diminution in the numbers of shrimps. The Thalassinidae 2 include certain crayfish-like species which live on our coast, burrowing in mud-flats, where they live concealed during the day. On account of their being of only medium size and difficult to obtain, they are commonly little known. Our Eastern species are Gebia affinis (Fig. 97) and Oallianassa stimpsoni. The hermit crabs (Paguriclce3) occupy a position inter- mediate between the long arid short tailed Decapods in 1 Palcemon Ohionis and Paleomonetes exilipes. 2 0a\da-a-Lvos, color of the sea. 3 -rrdyovpos, a kind of crab. 106 ZOOLOGY respect to the length of their abdomen. The abdomen is soft, and the animal protects it by inserting it within the coiled shell of some gastropod. Moreover, the abdomen is asymmetrical, being coiled to one side to correspond with the shape of the borrowed house (Fig. 99). The abdominal feet become degenerate, with the exception of the posterior pair, which are modified into a hook-like process, by means of which the crab maintains itself securely in the shell. FIG. 98. — Eupagurus longi carpus. Two individuals in shells. Photo, while alive by W. H. C. P. When one shell becomes too small, it is abandoned for a larger one. Numerous species of hermit-crabs occur on our coast, ranging from the shore line to a depth of several hundred fathoms. Eupayurus longicarpus is the little active hermit found in almost any tide-pool from Massa- chusetts Bay to the Gulf of Mexico. Hydroids, polyps, sponges, often attach themselves to these borrowed shells (Fig. 98) ; indeed, a Chinese hermit-crab always bears an anemone on its large claw, with which it plugs up the aperture when obliged to retreat within its shell. One of TIIK CKAVFISII AND ITS ALLIES 107 the East Indian hermit-crabs, the so-called palm-crab, feeds upon cocoanuts, which it opens by inserting its claws into the eyes and then breaking the shell upon the rocks. The Hippidae include certain oval animals, which bur- row, like a mole, head first, in sandy beaches. The name of our common eastern species, Hippa l talpoides? indicates this resemblance (Fig. 100). FIG. 99. — Eupayurus longlcarpus removed FIG. 100. — Hippa talpoides. from shell, x Ifc. Photo, by W. H. C.P. Nat. size. Photo, by W. H. C. P. The Brachyura are represented on our shores by three principal families, which may be designated as triangular crabs, arched crabs, and square crabs. The spider-crabs, or sea-spiders, as they are sometimes called, belong to the triangular crabs. As their name implies, their legs are very long and slender.3 These crabs frequent oyster-beds and sea-bottoms in general. When 1 From frrTTos, horse ; used by Aristotle as the name of a kind of crab. 2 Like talpa, the mole. 3 Fig. 101. 108 ZOOLOGY seen stalking over such uneven surfaces, the advantage of these stilt-like legs is at once evident. The surface of the body of some species of spider-crabs is hairy, entangling inorganic matter, while hydroids, barnacles, and algse attach themselves to the shell. Libinia emarginata and dubia, the former ranging from Maine south, and the latter from Cape Cod to the Gulf of Mexico, are our two species which FIG. 101. — Libinia dubia. One-third nat. size. Photo, by W. H. C. P. undergo such concealment. The great Japanese spider- crab is said to be the largest of all the Crustacea, some individuals measuring, from tip to tip of the first pair of legs, 18 to 20 feet. The edible crab is a typical arched crab. It is so called because the carapace is arched in front. The carapace is also broader than long, and narrower behind than in front. THE CRAYFISH AND ITS ALLIES 109 The legs of this family are short and broad, and in some species the posterior pair is especially broad — an adapta- tion for swimming. These crabs may be divided into two groups — the burrowing crabs and swim- ming crabs. To the burrowing crabs belongs the genus Cancer (Fig. 102), which includes the edible crab of Europe, especially prized in England, together with several American species; while our common edible, soft-shelled or blue crab, Callineetes hastatus (Fig. 103), and the beautiful "lady crab" (Fig. 104) belong to the swimming group. Representatives of other families of crabs are, however, eaten in various localities and by various peoples. For example, our little Pinnotheres Fia. 102. — Panopeus sac/i, allied to Cancer. The mud- crab. One-half nat. size. Photo, by W.H.C.P. FIG. 103. Callineetes Jiastatus, blue crab. Reduced to one-third. Photo, by W. H. C. P. 110 ZOOLOGY ostreum (Fig. 105), found in the mantle chamber of the oyster, is eaten by us together with the oyster or separately. FIG. 104. — Platyonichus oceltatus, lady crab. Reduced to one-third. Photo, by W. H. C. P. The fiddler crabs are representative of the square crabs. These are the familiar animals which crowd salt marshes and run sideways to and from their burrows. One claw is much larger than the other. When the crab is disturbed, the large claw is brandished in a manner which has been likened to the movements of a fiddle as one plays upon it. Grelasimus pugnax is the most abundant species, and ranges from Cape Cod to the Gulf of Mexico. Together with Cambarus it does much damage by burrowing in the levees of the Mississippi River (Fig. 106). FIG. 105. — Pinnotheres ostreum. X 4. From Rathbun. THE CRAYFISH AND TTS ALLIES 111 The economic im- portance of the Deca- poda may be inferred from the fact that the receipts for the lobster alone, taken and sold by United States fishermen, is estimated for 1892 FIG. 100. — Gelasimiift puynax. Nat. size. Fronto-dorsal view. Photo, by W. H. C. P. at one million dollars. The yield to Canadian fishermen was in ad- dition worth half a million dollars. From the United States Fish Com- mission Bulletin for 1890-91 we find that the blue-crab fisheries on the Atlantic and Gulf coasts re- turned almost half a million dol- lars, while the shrimp catch in the same waters brought nearly a quarter of a million dollars more. The latter industry on the Cali- fornia coast is much greater, for the shrimp trade of San Francisco Bay alone is valued at a quarter of a million dollars yearly. The remaining orders of Mala- costraca maybe briefly mentioned. The Stomatopoda* include only FlQ. 107. _ s?uMff enJ)9MS(J) the Squilla,2 the mantis shrimp, SO mantis shrimp. Dorsal aspect. From Bigelow. 1 (rr6/ia, mouth ; TTO^S, foot. 2 cric/XXa, classic name for a marine crustacean. 112 ZOOLOGY called because of a certain resemblance to the mantis insect (Fig. 107). This animal is found on our east coast, where it burrows in the sand. It is a little longer than a crayfish. Being hard to catch, it is not much used as food. The Cumacea include a few small marine Crustacea, not ordinarily seen. They are of interest be- cause of the reduced carapace which is transitional to the condition found in the lower Crustacea. The Isopoda 1 include FIG. 108. — Oniscus, the sow-bug. Dorsal view. Nat. size. Photo, by W. H. C. P. FIG. 109. — Talorchestia fangicorni*, the beach flea. Nat. size. Photo, by W. H. C. P. the sow-bugs or wTood-lice (Fig. 108), noteworthy for forming the largest group of land Crustacea, and certain marine and fresh-water groups. The Amphipoda2 are exclusively aquatic creatures, found under decaying vegetation on beaches of lakes or the sea (Fig. 109), and crawling amidst marine hydroids. Being laterally com- pressed, the Amphipods tend to lie on one side when at rest. 1 ftros, equal ; Trotfs, foot. , both ; TTOI/S, foot. THE CRAYFISH AND ITS ALLIES 113 Edible Lobsters* — The American lobster, Homarus Ameri- canus, differs little in appearance from the European lob- ster, H. vulgaris. Formerly the American lobster attained the greater size, but the excessive catches of our species in the last few years are rapidly doing away with this differ- ence. The so-called Norwegian lobster finds its way into European markets, while on our Californian coast the so- called spiny lobster or sea-crayfish takes the place of our true Atlantic lobster, and, like the latter, is said to be in danger of extermination on account of overfishing. Edible Crayfish. — The nearest fresh- water ally to the lobster — the crayfish — has not yet attained the pop- ularity in our markets which it possesses in Europe, particularly in France. So much is the crayfish esteemed in Paris that the enormous crayfish farms throughout France are unable to supply that city, consequently cray- fishes are imported in considerable quantities from Ger- many. In America, it is our French population mainly that makes a market for the crayfish. Astacus nigres- cens is the crayfish sold in San Francisco markets. On the Atlantic coast, New York and New Orleans are the main centres of consumption. Cambarus affinis, taken from the Potomac River, is the crayfish found in the spring in the New York markets. Later in the season this market is supplied by Q. virilis and immunis, which are shipped from Montreal, Milwaukee, and other Western cities. Edible Crabs. — Of the crabs which reach our market the most important is the blue crab. These crabs are kept moored in floating boxes until they have moulted, and then they are sent to market as soft-shelled crabs. 114 ZOOLOGY The shore crabs, Cancer, are little eaten in the United States.1 Edible Carididae. — The shrimps and prawns have within recent years begun to appear in large numbers in the Eastern markets. For many years the Pacific species FIG. 110. — Limulus polyphemus, the king-crab or horseshoe-crab. have been dried and shipped by the Chinese in large quantities to China. 1 Very unfortunate is the destruction of the "king-crab," Limuhis, which is only distantly related to the Decapoda. In Delaware Bay they are caught in great numbers and ground up as fertilizer. As they are taken only during the breeding season, they are being rapidly extermi- nated. The American Limulus belongs to an order entirely unrepresented on the European coast (Fig. 110). THE CRAYFISH AND ITS ALLIES 115 Development of Lobsters. — Lobsters lay eggs in July and August. In the fall they migrate to deep water, and pass the winter there. In the spring they migrate back to the shore — the females tarrying behind the males until the eggs of last summer, which she still carries attached to her swimmerets, shall be further advanced. In June the young hatch out, moult, and swim to the surface. The FIG. 111. — An early stage of develop- ment of egg. Appendages becom- ing bifid. Paired dotted areas above indicate eyes ; these are fol- lowed by the first three paired ap- pendages : antennules, antennae, and mandibles. Below in the mid- dle line is the forming tail ; above is the mouth. After Herrick. FIG. 112. — Surface view of egg nauphius. Antennas show begin- ning of segmentation; mandibles and maxillae seen on each side of the abdomen. Embryo 16-18 days old. X 25. From Herrick. female now moults, but does not spawn again for a whole year ; that is, she spawns in alternate years. The number of eggs carried varies with the age of the female ; middle- aged lobsters may carry up to one hundred thousand eggs, but the old or young ones as few as three thousand. The egg as freshly laid is about 1.5 millimetres in diameter and is stored with food material, called yolk, much as in the case of the hen's egg. As in the chick, the development 116 ZOOLOGY takes place, as it were, on top of the egg (Figs. Ill, 112). Eyes and mouth appendages early make their appearance; then the other appendages, and the tail (Fig. 113). For a long time the back of the thorax is greatly distended by the yolk stored there, and the eyes are huge (Fig. 114). Immediately after hatching, the young lobster is about one-third of an inch long. The eyes are still abnormally large, the telson is spatulate, and the abdomen is without FIG. 113. — Surface view of embryo FIG. 114. — Lobster embryo. Cl days with all of thoracic appendages old ; eyes have developed pigment, formed. The forked telson partly X 15. From Herrick. overlies the brain. Note the large eyes, which are yet without pig- ment. Embryo about 21 days old. X 25. From Herrick. swimmerets. On account of its resemblance to the Schizop- oda, the larva at this stage is known as the " Schizopod larva" (Fig. 115). In moulting for the fourth time, the exopods are lost from the future walking appendages, and the animal resembles a lobster except for its small size (Fig. 115#). During these early moultings the young lobsters undergo a terrible mortality, so that out of ten thousand embryos hardly two, on the average, survive. After the THE CE AY FISH AND ITS ALLIES 117 fifth or sixth moult the little lobsters sink to the bottom, and then begin their journey shoreward. From this time until they are about four inches long, only very few indi- viduals have ever been seen. This is due, it is said, to the fact that they hide deep down among the rocks, where they cannot be dredged. When they are four inches long or so, they become bolder, leave the rocks, and, like the FIG. 115. — Larval view of lobster, extracted from an egg which was about ready to hatch. The concretions in the intestine are destined to go into the newcuticula after moulting. X 25. From Herrick. adults, make burrows for themselves in the sand or under stones. Development of Crayfish. — The crayfish develops simi- larly to the lobster, — from a large egg filled with yolk. The early stages are much like those of the lobster ; but those changes which in the lobster take place during the first three stages of free life are in the crayfish passed in the egg. Consequently at the time the crayfish hatches it 118 ZOOLOGY is almost, but not exactly, like an adult crayfish except in size. The telson of the just-hatched crayfish has, to be precise, a somewhat more oval form, and the first pair of swimmerets are undeveloped; but these differences soon disappear. FIG. lloa.— Third larval stage, lateral view. Note the dif- ference between this and the adult. X 11. From Herrick. Regeneration of Lost Parts. — If you attempt to pick up a crab by one of its claws, you frequently find yourself in possession of a portion of the leg only, while the crustacean has made good its escape. Moreover, it will be seen that the leg always separates at a certain place ; namely, be- tween the second and third segments. This is the place where a fusion occurs between two segments which are free THE CRAYFISH AND ITS ALLIES 119 in the first larval stage. This power of defensive mutila- tion occurs in those appendages which are most apt to be seized, — namely, the five thoracic legs, — and is wholly under the control of the reflex nervous system, for it may occur when the entire voluntary nervous system has been removed. The leg of a dead crustacean shows no such capacity. If the leg of a lobster is cut off at some point distal to that of normal rupture, the limb will later be found cast off up to this point. Here a sort of double membrane or diaphragm exists, with a central opening only large enough to admit the passage of nerves and blood-vessels. Upon rupture this passage is soon plugged up by coagulated blood — clearly a device to prevent ex- cessive hemorrhages. Soon after a leg is cut off a papilla- like body grows out from the stump of the limb, develops into the shape of a small limb, and grows larger, with each successive moult, until the normal size is reached. The antennae, too, are much exposed to injury, but with them autotomy is not practised. They begin to grow out at the place of injury, and at least one moult is necessary for their complete restoration. Abnormalities in the claws of the lobster are not un- common. The thumb-like protuberances of the next to the last of the joints of the great claw is sometimes bifid, or carries a large wart. The finger which opposes the thumb is also sometimes forked (Fig. 116). Many of these abnormalities are probably due to injury of the claw; but others cannot be explained in this way. For instance, cases have been observed of lobsters having crushing claws of equal size on the two sides of the body. An antenna has been seen replacing an eye, and this result may be obtained by cutting off an eyestalk near its base 120 ZOOLOGY when an antenna will regenerate (Fig. 117), one or two extra oviducts may occur, or double monsters — sort of Siamese twins — may be hatched out. Similar monstrosities are found in other arthropods. Physiological Division of Labor. — The difference between a " highly developed " animal and a lowly organized one is not first of all a difference of size nor a difference in the number of parts, - just as a large population or numerous cities are not the pri- mary characteristics of a highly civilized state. But just as a complex civilization is one in which each of the different citizens has his own special task to per- form for the commonwealth, so a highly developed organism is one in which each different organ has its special r61e to play. The worm Nereis has more segments to the body than the crayfish, but these segments are very nearly FIG. 116,-Two abnormal claws, alike — the parapodia especially Upper figure shows a double are quite similar. In the crayfish, to^^rthere^extS on the other hand> the append- finger. From Herrick. ages are dissimilar. Each pair has a special function to perform and is specially adapted, often complexly fashioned, to meet this need. What is true of the appendages is like- THE CRAYFISH AND ITS ALLIES 121 wise true, to an equal degree, of the internal organs. The internal organs of Nereis are repeated in each segment; but in the crayfish the egg-ducts lie in one segment, the heart in another part of the body, and so on. Some of the seg- ments have given up one or more functions to perfect a FIG. 117. — Eyestalks of a Decapod dissected out. On the right an antenna has regenerated in place of the amputated eye. opt., optic nerve. After Herbst. single one in which it has specialized. There has been a division of labor between the different parts of the body, and in consequence a greater perfection in the performance of each function. More perfect fulfilment of function is the result of physiological division of labor, just as a higher civilization is the result of individual division of labor. 122 ZOOLOGY APPENDIX TO CHAPTER VII KEY TO THE SIX CHIEF ORDERS OF MALACOSTRACA Body segments, 20 ; abdomen with 7 segments ; at least 1 pair of maxillipeds. 61. Cephalothorax with carapace, at least 2 pairs of maxillipeds [Thoracostraca]. Ci. Eyes stalked. d\. No uncovered thoracic segments ; 3 or 2 pairs of maxillipeds, and 5 or 6 pairs of legs . . . * c?2. 3 free thoracic segments ; 5 pairs of maxillipeds ; 3 pairs of legs Cg. Eyes not stalked ; 4 to 5 thoracic seg- ments not covered by carapace ; 2 pairs of maxillipeds ; 6 pairs of thoracic legs 62. Cephalothorax without marked carapace; usually 7 free thoracic segments ; only 1 pair of maxillipeds ; eyes not stalked [Arthrostraca]. d. Body usually broad ; abdomen with short, often-fused segments, and with gills on legs ...... c2. Body laterally compressed ; abdomen mostly elongated, with 3 pairs of swim- ming legs, and behind them 3 pairs of springing legs . ... a2. Body segments, 21, enclosed in bilobed shell ; abdomen with 8 segments ; the last 2 without appendages ; no maxillipeds [Leptostraca] Podopthalmata (Ex. Crayfish) Stomatopoda Cumacea Isopoda Amphipoda Nebalice The crayfish belongs to the order Podopthalmata. The following is a key to the most important families of this order : — a\. 3 pairs of maxillipeds which differ in form from the following 5 pairs of thoracic legs ; the latter are locomotor, and often end in pincers [sub- order Decapoda]. APPENDIX TO CHAPTER VII 123 61. Body mostly depressed ; antennae short ; abdomen short and folded under the cepha- lothorax, with 1 to 4 pairs of appendages, and usually without tail-fin [superfamily Brachyura] . cj.. Male duct opens on thoracic plate ; ce- phalothorax usually quadrangular, at times transversely oval; anterior lateral area (liver area) of carapace small ; usually fewer than 9 pairs of gills; orbits look forward or obliquely downward . Catometopa (Square Crabs ; Fiddler-crabs) c2. Female opening on broad thoracic plate ; male opening on coxa of 5th pair of thoracic legs ; 9 pairs of gills. di. Cephalothorax broad, diminished be- hind, bowed in front ; liver area large ; orbits directed obliquely up- ward and forward . .. -. .. Cyclometopa (Arched Crabs) d-2. Cephalothorax triangular, anteriorly pointed, with longer or shorter ros- trum ; liver area small ; orbits di- rected outward . . . . Oxyrhyncha (Triangular Crabs ; Spider-crab?) 62. Body mostly elongated ; antennae long ; ab- domen long, not bent under, or only partly so, typically with 5 pairs of legs and a large tail-fin [superfamily Macrura]. ci. Last pair of thoracic legs shoved back- ward and rudimentary. di. Last thoracic segment not free ; ab- domen with hard shell, hinder half turned under; first pair of legs typically non-chelate . , . ; Hippidce (Mole-crabs) d2. Last thoracic segment free ; abdomen typically with thin cuticula, un- symmetrical and with rudimentary legs ; first pair of legs very large, chelae unsymmetrical . . . Paguridce (Hermit-crabs) 124 ZOOLOGY C2. Last pair of thoracic legs not shoved backward. di. Antennae, without squame ; first pair of thoracic legs chelate ; cephalo- thorax with 2 longitudinal lines . d%. Antennae with squame. e\. Squame small ; antennules and antennae near each other ; first pair of thoracic legs very heavy with great chelae; cephalo- thorax with cross-suture ; gills brush-like Thalassinidce Astacidce (Ex. Crayfish) €2. Squame large ; antennae usually under antennules ; first pair of thoracic legs with small chelae ; cephalothorax without cross-suture, gills laminate {Shrimps and Prawns) 2 pairs of maxillipeds resembling the 6 following pairs in being bifid [suborder SchizopodaJ. CHAPTER VIII THE DAPHNIA AND ITS ALLIES Relationships. — Daphnia1 belongs to the division of Crustacea called Entomostraca.2 The Entomostraca 3 are distinguished from the higher Crustacea — the Malacos- traca — by the negative character that the number of segments and appendages in the body is variable, instead of there being constantly 19 pairs of appendages. The group of Entomostraca to which Daphnia belongs comprises the more primitive of living Crustacea. They occur in both fresh and salt water and, excepting Protozoa, are the most abundant aquatic animals. They are of great economic importance, since they constitute the main food supply of fish. On the coast of Norway and Scotland the fishermen prepare for a catch of herring or mackerel when the sea becomes red with Entomostraca. Whalers like- wise seek their booty where these Crustacea are abundant on the open seas, for even the whalebone whales devour the small animals in great quantity, straining them out of the sea-water by means of their whalebone strainers. De- spite all their enemies, the numbers of Entomostraca are maintained by virtue of an enormous fertility. The 1 From Aa0j/r;, daughter of the river-god Peneus ; she was transformed into a laurel tree. 2 evTojjwv, cut into, segmented ; 6ffrpaKov, shell. 8 The five orders of Entomostraca may be distinguished by means of the key given at the end of this Chapter, page 131. 125 126 ZOOLOGY Entomostraca are rich in species also, partly because they occur in such diverse environments. Thus they live in fresh water, in the sea, and even in the Great Salt Lake and in vats where salt is crystallized out. They live in little pools, such as dry up in summer. They are found also as parasites on the gills or in the skin of fishes. Habitat and Food. — Daphnia1 lives in ponds, lakes, and slow-running streams over all the globe. During the fall in northern latitudes the Daphnias, of at least certain species, lay fertilized eggs, called winter eggs, which may lie dormant, however, not merely for the winter but throughout an entire year. During most of the year females alone occur and unfertilized "summer eggs" are alone produced. The abundance of Daphnia in any pond is determined by a number of causes. One of the most important of these is food. The food of Daphnia consists chiefly of fresh-water algae, such as nostocs and diatoms ; and it has been shown that the abundance of Daphnia in a pond is closely determined by the abundance of the kind of alga 1 Key to the principal genera of the family Daphnidse : — a\. Head rounded, not beaked. bi. Antennules long; abdomen not wholly cov- ered by shell . . ./: .' . . Moina b-2. Antennules short; whole body enclosed in shell . . .,.-./.„ . . CeHodaphnia «2. Head beaked below. 61. Beak slight ; shell angled below or extending in long spines from lower angle ; pigment spot roundish Scapholeberis ft2- Shell rounded below, with a blunt spine above ; pigment spot elongate .... Simocephalus &3. Shell extending in sharp spine at upper pos- terior angle ; pigment spot small . . Daphnia THE DAPHNIA AND ITS ALLIES 127 which forms its principal food. Another factor upon which the number of Daphnia in a pond depends is tem- perature. A high temperature seems to be unfavorable to Daphnia, so that not the summer, but the spring and autumn are its periods of maximum reproductive activ- ity. This activity is like- wise checked in winter even though there is plenty of food. The family Branchiopoda x is closely allied to the Clado- cera. The common repre- sentative of this family, Branchipus, has an elongated, distinctly segmented body which carries eleven pairs of lobed, leaf -like feet, func- tioning both as respiratory and locomotor organs. Like Daphnia, Branchipus pro- duces winter eggs which can withstand desiccation even FIG. 118. — Apwt glacialis, ventral aspect, abd. /., abdominal feet; ant. 1, antennule ; ant. 2, antenna ; Ibr., labrum; md., mandible; mx., for years; indeed, in SOme first maxilla; ov., aperture of ovi- cases, a certain amount of duct ; s/.^ sub-frontal plate ; sh. yl., shell-gland; th.f., thoracic feet; th.f. 1, first thoracic foot. After Bernard. desiccation is a prerequisite of hatching. Apus differs from Branchipus in having a broad shield (Fig. 118). The family Ostracoda2 comprises some very abundant, *, foot. , shell of a testacean ; e?5os, like. 128 ZOOLOGY minute, bean-shaped little crustaceans, which have to move their, appendages very vigorously to support their heavy bodies in the water. The Ostracods are found in almost all pools and streams, especially in the early spring. Many of them seem to be exclusively parthenogenetic. FIG. 119. — Acartia, a marine Copepod. Greatly magnified. Photo, by W. H. C. P. Of the Copepoda l the commonest fresh- water genus is Cyclops, which occurs in a similar habitat with Daphnia and is sometimes found even in pure drinking water. The female carries a conspicuous egg-sac 011 each side of the abdomen, and reproduction occurs with such rapidity that oar ; TTO^S, foot. THE DAPHNTA ANT) ITS ALLIES 129 one Cyclops might, under the most favorable conditions, have 5,000,000,000 descendants in one year. It is conse- quently easy to understand how Cyclops often becomes the most abundant entomostracaii in our waters, and how in some lakes it has been found that there are over one million of them to each square metre of water surface. Large numbers of the Copepoda are marine. One of the most common is Acartia (Fig. 119), which swarms to such FIG. 120. — Mussel-shell bearing barnacles (Balanus). Photo, by W. H. C. P. an extent on the surface of the water as to make great phosphorescent areas. Barnacles are the only attached non-parasitic Crustacea. Certain species of them are found fastened to rocks on the seashore at low-tide mark. If you watch barnacles in rock pools, you can see them open the valves of their shells, protrude their elongated appendages, which together form a sort of rake, and pull in particles which happen to be float- ing about them. Other species of barnacles attach them- selves to floating seaweed, ship bottoms, and whales ; under these circumstances, despite their sessile habit, they enjoy a constant change of locality. Barnacles doubtless gain great protection from the circumstance that they are 130 ZOOLOGY sessile and enclosed in shells ; but their peculiar habits have given rise to certain peculiarities in reproduction. They are hermaphroditic; i.e. both male and female germ- cells occur in the same individual. Despite this fact, dwarf male individuals are occasionally found inside the shell of the barnacle ; these are known as " complemental males." The general form of the barnacles has also be- come greatly modified by their sessile habit, so that they were long regarded as mol- lusks, until it was shown that the larvae are almost exactly like those of other Ento- mostraca. Trilobites1 are extinct giant ' Entomostraca, closely allied to Branchipus. They were immensely abundant in early geologic times, and their re- mains form a large part of certain rocks. They had a segmented body, with bifid appendages and long antennae, FIG. 121. - A restoration of the and their compound eyes were borne on the great frontal shield. Some of them were nearly half a metre long. ventral aspect of a Trilobite. Note in particular the charac- ter of the appendages. After Beecher. Having three lobes. APPENDIX TO CHAPTER VIII 131 APPENDIX TO CHAPTEE VIII KEY TO THE FIVE ORDERS OF ENTOMOSTRACA a\. Free-living or parasitic inhabitants of the sea or of fresh water. 61. 2 pairs of maxillae. ci Mandible without palp ; 4 or more pairs of foliate swimming legs behind maxillae [Phyllopoda]. d\. With 10 to 40 pairs of legs . . Sranchiopoda (Ex. Branchipus) eZ2- With 4 to 6 pairs of legs . . . Cladocera (Ex. Daphnia) Co. Mandible with leg-like palp ; only 2 pairs of appendages behind maxillae . . Ostracoda bo. Only 1 pair of maxillae, followed by 4-5 pairs of bifid, oar-like feet ; often deformed as a result of parasitism . . . ... Copepoda (Water-fleas) a2. Sessile marine animals, whose body is surrounded by a usually calcified mantle ; 6 pairs of tendril- like feet Cirripedia (Barnacles) Key to the principal families of Cladocera, to which group Daphnia belongs : — a\. Body enclosed in a bivalve shell ; mandibles trun- cate below ; maxillae distinct, spiny. 61. 6 pairs of similar, foliaceous, distinctly branchiate feet ; swimming antennas with 2 unequal rami ; intestine straight . . . Sididce 52. 5 (or 6) pairs of feet, the anterior pair more or less prehensile and destitute of branchiae. GI. Rami of antennae 3- and 4-jointed ; 5 pairs of feet, the last with a curved appendage guarding the branchial sac ; antennules of the female sort, 1-jointed Daphnidce 132 ZOOLOGY C2. 6 pairs of feet ; antennules elongated, many-jointed • Bosminulce C3. Antennae with both rami 3-jointed ; in- testine convolute ..... Lynceidce 0,2- Body wholly or nearly destitute of a bivalve shell ; feet not branchiate, spiny ; abdomen curved, ending in two long stylets ..... Polyphemidce CHAPTER IX THE EARTHWORM AND ITS ALLIES Relationships. — : Earth worms1 belong to an order of Annelids known as Oligochieta.2 This group is distin- guished by a prevailingly non-marine life, by the absence of parapodia, by few bristles, and by the absence of tenta- cles, palps, cirri, and gills.3 Habits. — Earthworms, as the name implies, are inhabit- ants of the ground, through which they burrow and in FIG. 122. — Flash-light photograph of earthworm and slug crawling on a pave- ment at night. Photo, by D. and S. 1 There are not very many kinds of terrestrial Oligochseta. The prin- cipal American species may be distinguished with the aid of the key given in the Appendix to this Chapter. 2 (JXfyos, few ; xa^T77: hair. 8 The Oligochreta exhibit two principal subdivisions ; the first of which includes terrestrial species of the single family Lumbricidae, and the second various aquatic families, — a key to which is given on page 144. 134 ZOOLOGY which they gain their food. They sometimes come to the surface at night in search of companions and food (Fig. 122). Even during the day in rainy weather they extend the anterior end of the body out of their burrows. Earth- worms, found on the surface at other times, have, for the most part, been parasitized by a fly, and are in consequence weak or dying. During the daytime, if the surface mois- ture permits, they lie near the mouth of their burrows, probably for the sake of the sun's warmth. In this posi- tion they can be seen by looking down into the holes. At such times they are often caught by birds. In dry weather, or when the ground is freezing, earthworms burrow deep to a moist stratum, or to below the frost line, and hiber- nate there. Food. — Earthworms are omnivorous. As they burrow through the ground, the earth is taken into the alimentary tract, and the digestible particles are dissolved out and absorbed as food. Earthworms can, however, be fed upon green and dead leaves, decaying wood, seedlings, bits of flesh, and even filter paper. Earthworms have the habit of dragging into their burrows leaves which they intend to devour. There the leaves are moistened with a fluid excreted by the worm. This fluid partially digests the food. After being taken into the alimentary tract, the food reaches an organ of the canal known as the gizzard. This part has thick muscular Avails, and contains in its cavity small stones ; by the action of both the muscular gizzard and the small stones, the food is ground up in much the same way as are the grains of corn by the aid of stones in the gizzard of a hen. Resistance and Regeneration. — The capacity which earth- worms possess of resisting certain untoward conditions is THE EARTHWORM AND ITS ALLIES 135 very great. Thus they may be kept for months in a moist vessel without food, or with only filter paper, with- out starving. On the other hand, they die in a dry atmos- phere in a few hours, whereas they may be submerged in water for several days without injury. Very remarkable is their power of healing after injury. If an earthworm be cut in two near the middle, and the halves be kept under favorable conditions, each half may develop its missing organs so that two complete worms will result. The anterior half of one worm may be attached to the hinder end of a second worm by the cut edges, owing to the fact that the cut edges grow together. This operation is called grafting. Economics. — Earthworms are, to a certain extent, in- jurious to vegetation, since they eat tender seedlings and roots, but, on the other hand, they are almost indispensable to agriculture. Their burrows permit rain to percolate deep into the ground, instead of running off on the sur- face. They keep the soil loose, facilitating the penetration of the roots of plants. The earth that passes through their bodies is ejected on the surface of the ground near the openings of their burrows, and is called a " casting." By means of castings the deeper-lying earth is brought to the surface, and the surface layer of rich earth, called " vegetable mould," is in this way increased in thickness by additions to its upper surface. The thickness of the layer of mould which the castings of one year, if uniformly spread out, would make has been estimated by Darwin to be in England about two-tenths of an inch. Most of these castings are merely taken from the deeper-lying mould, but they are enriched by the intestinal secretions in pass- ing through the body of the worm. These intestinal secre- 136 ZOOLOGY tions are said to have the power of slowly dissolving sand and thus of turning it into soiL Darwin says, " It is a marvellous reflection that the whole of the superficial mould over any smooth expanse has passed, and will again pass, every few years, through the bodies of worms. The plough is one of the most ancient and most valuable of man's inventions, but long before he existed the land was, in fact, regularly ploughed, and still continues to be thus ploughed, by earthworms;" The group to which earthworms beloeg is closely related to that which includes Nereis of the seashore. They are both ringed worms or Annelids.1': But whereas Nereis and its allies have parapodia provided with numerous bristles, the earthworm has no parapodia, and only a few bristles on each segment. The group to which Nereis and its allies belong is called (see Chapter X) Polychseta, and the group to which the earthworm belongs is appropriately named Oligochceta. The aquatic Oligochaeta2 are among the commonest inhabitants of ponds and ditches, living sometimes in the mud and sometimes at the surface of the water. Tubifex3 is common in slow-running brooks, and lives in the mud of the bottom, forming tubes in it. The thread-like bodies of the worm are stretched up beyond the surface of the mud and wave in the water in graceful undulations. Often the worms are so numerous that their reddish color gives a decided tinge to the bottom. They thrive well in fresh- water aquaria. 1 Annulus, a little ring. 2 A key for the determination of the principal families of aquatic Oligo- chseta is given in the Appendix to this Chapter, page 144. 3 tubus, tube ; /acere, to make. THE EARTHWORM AND ITS ALLIES 137 Dero1 is very common on the surface of ponds, particu- larly in the midst of duck-weed (Lemna), the leaves of which it cements together to form a floating tube in which it lives, and by which it is accompanied in all its migra- FIG. 123. — Dero, the duck-weed worm. Enlarged. After Reighard. The lettering is as follows : or., mouth; phx., pharynx; oe., O3sophagus; sg. o., segmental organ ; in., intestine; pav., pavilion or tunnel; dg. app., finger- like appendages. From Reighard. tions. Dero can also be told by the sort of funnel at the hinder end of the transparent body, from the margins of which finger-like filaments arise which aid in respiration (Fig. 123). Nais2 does not construct tubes, and it has no respiratory to skin (= flay). a water-nymph. 138 ZOOLOGY filament at the hinder end of the body (Fig. 124). It also has eyes ; while Dero has none. Both Dero and Nais have the interesting habit of reproducing by dividing the body transversely. In the middle of the body tentacles begin to arise, a new mouth is formed, and the worm constricts into two. Indeed, sometimes several new heads may be forming in the midst of a single worm. This habit is of advantage not only in multiplying the number of individuals of the species, but also For if, by chance, the larva of FIG. 124. — Nais: a, mouth; b, anus; c, intes- tine. From Leunis. as a means of protection, the water-beetle Dytiscus seizes a Nais and bites it in two, the part which escapes can go on developing new individuals. The slow-moving, burrowing habit of the earthworm has led to a nearly complete absence of such appendages as Nereis possesses. There are other ringed worms in which the burrowing habits have led to a loss even of the segments in the adult. This is the case in the group Gephyrea.1 1 ytyvpa, bridge ; because they were once considered to bridge the gap between holothurians and worms. . — Phasco- , Gephy- rean. One-fourth nat. size. From Leunis. THE EARTHWORM AND ITS ALLIES 139 anksek This group contains several rather rare animals. One of the commonest is Phascolosoma,1 which is a tough but smooth-skinned, cigar-shaped worm, which one can dig up on our sandy beaches (Fig. 125). One end is pointed ; from the other a great proboscis terminating in tentacles surround- ing a mouth can be extruded. Another species found on our beaches after a storm, something like a small cucumber in shape and size, has a row of bristles at each end, indicating its relationship with the bristle-bearing worms. This species, Echiurus,2 is seg- mented when young like Nereis, but eventually it loses its seg- mentation (Fig. 126). Several species of Sipunculus are edible, and are held in esteem by the Chinese. . To the account of the Oli- gochaeta above given may be added some statements concern- ing a group of annelids of very different appearance. The leeches, or "blood-suckers," are flattened worms, which, like the earthworm, show metamerism ; that is, there is a repetition of the in- ternal organs. They are also segmented ; that is, the body has external rings, although they may be obscure. One segment does not, however, as in the earthworm, FIG. 126. — Echiurus. About one-half nat. size, prob., proboscis; ant. set., anterior setae; post, set., posterior setae. After Greef, from Par- ker and Haswell's " Text- book." 1 <£, to steal. 2 fiptov, moss ; ^or, animal. FIG. 129. — Bugula turrita, a marine ectoproct. A colouy, magnified 1.5 diams. Photo, of living animals by W. H. C. P. r FIG. 1I>0. — Plumatella poh/morpha, a fresh-water ectoproct, magnified 1.5 APPENDIX TO CHAPTER IX 143 tinguislied, the Endoprocta (Fig. 128), iii which the individual consists of a long stalk and a " head " or body proper ; and the Ectoprocta (Figs. 129-131), usually without such a stalk. The Ectoprocta are the prevailing type. The marine species form lace-like mats on sea- weed or stand up as branching, bushy colonies (Fig. 129). Some of the fresh- water forms make loose, antler- like colonies (Fig. 130), while others lie on the surface of a more or less spherical mass of jelly which they have themselves secreted (Fig. 131). FIG. 131. — Pectinatella magnified, a dense complex of colonies, growing upon a stick. Each star-shaped group represents a single colony. One-half uat. size. Photo, of living mass by W. H. C. P. APPENDIX TO CHAPTER IX KEY TO THE PRINCIPAL SPECIES OF EARTHWORMS OF THE UNITED STATES a\. Clitellum begins on segment xiii or xiv ; $ pore, on segment xviii or xix ; 2 gizzards in segments v and vi. 61. 2 dorsal vessels ; lives in soil of prairies 62. 1 dorsal vessel ; lives in river-bottom land a-2. Clitellum does not begin in front of segment xviii ; $ pore on segments xii and xiii, or (usually) xv. 61. Prostomium incompletely divides buccal lobe [genus Allolobophora]. ( Diplocardia \ communis D. riparia 144 ZOOLOGY d. Tubercles on segments xxviii-xxxi ; ill- smelling ; purple-banded ... A. fcetida c-2. Tubercles on segments, xxxi and xxxiii . A. cattyosa c'3. Tubercles on segments xxvii, yxviii ; color reddish brown .... A. tumida c4. Tubercles on segments xxiv-xxx ; about 100 segments ..... A. parva 65. Tubercles on segments xxviii-xxx . A. subrubicunda c6. Tubercles on segments xxix-xxxi (occa- sionally xxix, xxx); number of seg- ments, 150 . . . . . . A. rosea bz. Prostomium completely divides buccal lobe [genus Lumbricus]. Ci. Tubercles on segments xxviii-xxxi ; red- brown or purple ; about 120 segments . L. mbellus c2. Tubercles on segments xxxiii-xxxvi ; number of segments, 180 L. herculeus KEY TO THE PRINCIPAL FAMILIES OF AQUATIC OLIGOCH^STA «i. Dorsal blood-vessels visible only in the anterior part of the body ; farther back, as intestinal sinus, disappearing underneath the intestinal glands . . . '.""'. • • • Enchytrceidas a*. Dorsal blood-vessels running on top of food canal and visible throughout its entire length. 61. In each segment, except the first, contractile lateral blood-vessels Lumbriculidas b». Lateral vessels contractile only in anterior segments. Ci. Dorsal and ventral vessels united in each segment, except in the first 5, by 2 lateral vessels . . . . Tubiflcidce (Ex. Tubifex) c2. Dorsal and ventral vessels united in each segment by a lateral vessel . . . Naidw (Exs. Nais, Dero) CHAPTER X NEREIS AND ITS ALLIES NEREIS1 is one of the commonest worms found on our seacoast. It occurs in sandy or muddy beaches, at or below low-water mark, especially where tidal currents flow swiftly. It inhabits burrows, which it makes in the sand and lines with a mucilaginous secretion to bind together the walls of sand or mud. At certain seasons of the year, during the breeding season, these worms may be found swimming near the surface of the sea. Nereis lives on both plant and animal food. To capture its prey it thrusts out a long proboscis, provided with two powerful jaws. The thrusting out consists essentially of a rolling inside out, — just as the finger of a glove may be rolled inside out. When the proboscis is rolled in again, the jaws, retaining their grip on the food, carry it into the food canal. While many kinds of small animals serve Nereis as food, it is itself devoured by various fishes which dig it out of the sand or capture it when it swims free at night or during the breeding season. Such a favorite with fishes naturally makes excellent bait, and is well known to fishermen under the name "clam-worm" or "sand-worm." Nereis is distinguished by the fact that its segments are numerous and nearly all alike, and bear appendages of similar form. The single pair of jaws on the proboscis is , daughter of Nereus, one of the Nereids, or sea-nymphs. L 145 146 ZOOLOGY characteristic; and the four eyes on top of the head, com- bined with two antennae and two palps, serve to determine its family with precision. The par apod ia have a dorsal and a ventral cirrus. The commonest species on the coast of New England and in Long Island Sound is Nereis virens,1 which grows to a length of thirty centimetres. Its color is dull green to bluish green, and iridescent. The gills on the parapodia are green at the head end, but farther back they become bright red, owing to the blood which flows through them. This species lives in northern seas, and is found on the coasts of Great Britain, Norway, Labrador, and south FIG. 132. — Euglycera. One-half natural size. Photo, by W. H. C. P. to Long Island Sound. South of Long Island Sound the commonest species is Nereis limbataf1 which grows to a length of, at 'most, only fifteen centimetres, and is of a dull brown or bronze color. This species is found as far south as South Carolina. Often associated with Nereis in sandy beaches is a large, strong, flesh-colored worm, pointed at both ends, so that the head is not nearly as evident as in Nereis, and having small appendages, so that it looks smooth like an earthworm. This 1 Green. 2 Bordered or edged. NEREIS AND ITS ALLIES 147 is Euglycera.1 Its proboscis has four jaws, situated at the corners of a square, instead of two as in Nereis. The pointed head and powerful writhing muscles enable the animal to burrow with great rapidity (Fig. 132). A second kind, Autolytus,2 is a small animal which lives in little tubes attached to algse or hydroids (Fig. 133). The parapodia at the anterior half of the animal are different from those at the posterior half, for the latter are large and fitted for swim- ming. Eventually one of the middle segments of the body becomes trans- formed into a head, with eyes and tentacles, then the whole of the hinder half breaks off spontaneously. The newly formed head is now the head end of the new individual. This individual leads a different kind of life from the half which remains in the tube, for it swims freely in the water. The separated individuals are either male or female, whereas the part which lives in the tube never pro- FlG. 133. -Autolytus, duces eggS, but merely forms a new representative of a fam- , ., '. ,, ,, , , -T . _ ily of Polychfeta in tail every time the old tail is cut oft which the animal buds to form a sexual individual. off male or female in- ;%.,,., 0 dividuals from its hinder A third kind, Lepidonotus3 is 'end. bud, head of the characterized by the possession ot budded individual. After A. Agassiz. 1 e&, typical ; FXike/ra, a woman's name, also applied to a family of Polychseta. Euglycera means typical of the family Glyceridae. 2 atfr6s, self ; Xtfw, to separate ; hence, self-separating. 3 Xe7r/s, scale ; J/WTOS, back. 148 ZOOLOGY FIG. 134.— Lep- idonotus, the scaled worm. Nat. size . Photo, by W. H. C. P. a double row of scales covering over the back (Fig. 134). These scales are outgrowths of the dorsal part of the parapodia, and serve for respiration. In allied genera the scales are covered with bristles, which may be so very long and abundant as to hide the scales. They produce a brilliant iridescence. One of these worms with the great bristles may be several inches long and relatively broad, and is commonly known as the "sea-mouse " (Fig. 135). Both Lepido- notus and the sea-mouse occur in out-of-the- Avay places, — crevices of rocks at low tide or fairly deep water, — so that they are not com- monly seen at the seashore. The sedentary Polychaeta are mostly smaller and less familiar animals than the free-living Polychseta, but they have an interest for us in showing how greatly modified an organism becomes when it takes on a sedentary life. Its swimming appendages become rudimen- tary; its eyes are usually lack- ing; there is no protrusible proboscis armed with powerful jaws ; the gills become grouped almost exclusively about the ™^"£STSe- "PPer end of the body, where NEREIS AND ITS ALLIES 149 they can be thrust out of the tube ; the mouth comes to lie at the bottom of a funnel, which receives as food small parti- cles floating in the water; even the segmentation of the body becomes lost at the hinder end of the animal ; in a word, all those organs which are useful for active carnivo- rous life have become re- duced to the bare needs of a quiet herbivorous life. FIG. l.'JG. — Amphitnte, removed from its tube. Nat. size. Photo, by W.H.C.P. FIG. 137. — Polycirrus, the blood spot. Nat. size. Photo, by W. H. C. P. The first of these sedentary worms that we have to con- sider is not completely modified from the type found in free-living species. Cirratulus 1 lives in tubes in mud or sand. It is yellow 1 From cirrus, curl, ringlet. 150 ZOOLOGY or orange in color, and has long cirri, which, arising from nearly every segment, reach out in all directions. These function as gills, and when broken off may remain alive for days. Clymenella,1 which looks like a reddish, jointed straw, builds tubes of agglutinated sand, and has a serrated, funnel- shaped tail end. Its parapodia are very small (Fig. 139). FIG. 138. — Tube of Cistenides. Nat. size. Photo, by W. H. C. P. Fio.139. — Clymenella,straw- worm. The anterior seg- ments only are shown. After M. Lewis. Amphitrite2 (Fig. 136) builds firm tubes of sand. From the head spring numerous tentacles and three pairs of blood- red gill-tufts. The body is large anteriorly but becomes slender behind, where there are no bristles. Allied to Amphitrite are a large number of common worms found on our coast. Polycirrus, or the blood-spot (Fig. 137), is somewhat smaller than Amphitrite and characterized by a 1 Diminutive of KXv^pi?, daughter of Oceanus. 2 'A/j.iTpiTi], wife of Neptune, goddess of the sea. NEREIS AND ITS ALLIES 151 uniform crimson color and a large number of cirri massed at the head. The tubes made by some of the Terebellidse are very beautiful. The tube of Cistenides (Fig. 138) is found in the sand under stones and is composed of grains of sand cemented together and regularly arranged so as to form a firm wall. Finally, Serpula1 secretes crooked, round calcareous tubes, which may be found adhering to stones near low water (Fig. 140). From the mouth of the tube the head, with its tentacles, may be protruded, but it quickly re- tracts from danger and closes the open- ing of the tube as a marine snail does its shell, by means of an operculum or lid. Some worms have gained a parasitic FIG. 140. — Serpula tube on a bit of oyster shell that is perforated by the boring sponge. The tube lies in the centre of the figure. Nat. size. Photo, by W. H. C. P. a habit, and in con- sequence have become much modified in form and struc- ture. Sucli is the case with some of the round- worms. Some of these are thread-like, live in springs or pools, and are regarded by the uninitiated as animated horse-hairs. Others are spindle-shaped, as for example the " vinegar eel " and the round- worms that are common in stagnant water. Others live in the food canal, as for example the stomach worm (Ascaris) of the horse and the 1 Diminutive of serpens, serpent. 152 ZOOLOGY B FIG. 141. — Trichina. A, encysted form in muscle of pork; B, female; (7, male ; bh, envelope of cyst ; cy, cyst ; de, male duct ; e, embryos ; /, fat globules; h, testis; mf, muscle fibre; oe, pharynx; ov, ovary; no, opening to egg duct; zh, cell masses in intestines. After Glaus. NEEEIB AND ITS ALLIES 153 pin-worm of man. Others still penetrate into the mus- cles, and cause great pain and often death. Such is the pork- worm, Trichina,1 which gets into man through un- cooked pork, multiplies in the food canal, migrates in great numbers into the muscles and encysts itself there (Fig. 141). Another group which is largely parasitic is that of the flatworms. Some flatworms live free in ponds. They will be found abundantly among plants taken from small ponds in the summer and autumn, and are commonly known as Pla- naria2 (Fig. 142). They may be recognized not only by their flattened form, but also by a curious proboscis which pro- trudes from the middle of the under side of the body and bears a mouth at its tip. These creatures have a marvellous FKi. 142._Species of fresh-water power of regeneration, SO that Planaria. 1, Dendrocoelum every piece into which a worm is cut will reproduce an entire one (Fig. 143). If the worm is mutilated but not wholly cut in two, bizarre forms may result by a modified tendency to regenerate (Fig. 144). Other flatworms are parasitic, such as the liver-fluke of the sheep (Fig. 145). This destructive parasite has a lacteum, cream color; 2, Pla- naria maculata ; 3, head end of same to show light streak. After Woodworth. , hair. 2planus, fiat. 154 ZOOLOGY complicated series of stages to go through before it be- comes adult. Thus the flukes in the liver of the sheep produce eggs which develop into embryos. These em- bryos get out of the liver into the food canal, and thence 00' u ec.10. "J Marcti13.Apr.4-. Jan.25. FAS. Feb.17 Jec.W. Jan.25. Feb.5. FIG. 143. — Showing results of cutting Planarians into two pieces; the pieces develop into entire animals. After Morgan. to the exterior. If they are deposited near a pool of water, they may develop further, otherwise they must die. In the water a ciliated larva a hatches from each egg, swims about for a time until it finds a fresh-water snail, bores into it, and encysts itself there. In this i Fig. 146, A. NEREIS AND ITS ALLIES 155 FIG. 144. — Showing abnormal forms resulting from mutilation of Pla- narians. After Van Duyne. encysted stage the worm is known as a "sporocyst," because it is full of germs (spores) of a new genera- tion.1 The spores develop in the snail into curious organisms, a sort of second- ary larvae known as redia.2 The redise may produce, by a kind of internal budding, new redise, and so on re- peatedly, until at last, on the death of the snail, or from some other cause, the last generation of rediae produces liver-flukes.3 The young liver-flukes wriggle out of the snail, attach them- selves to damp grass, lose their tails, and encyst them- selves. If these cysts be eaten by a sheep, they develop in the sheep's body into an adult liver-fluke (Fig. 145). Thus the stages which we can recognize in the liver-fluke are : — First generation : egg from liver-fluke, larva, and adult sporocyst. Second generation : redia (this may be several times repeated). Third generation : " cercaria " larva, encysted larva, and adult liver-fluke. 1 Fig. 146, B. 2 Fig. 146, C. 3 These, while young, have tails, and are called "cercaria. FIG. 145. — Distomum, the liver-fluke. Nat. size. Excr., excretory pore; mo., mouth; repr., reproductive aperture ; sckr., posterior sucker. From Parker and Has- well. " 156 ZOOLOGY Another flat worm is such an abject parasite that it has lost most of the organs usually possessed by worms. This is the tapeworm (Fig. 147). When the eggs of the tape- worm are taken into the body of an herbivorous animal, the embryos develop there for a way and then stop. When flesh containing these embryos is eaten by a carnivorous FIG. 146. — Development of Distomum. A, ciliated larva ; B. sporocyst con- taining developing rediae ; C, redia, containing a daughter redia and embryo liver-flukes; D, free-swimming, tailed larva of liver-fluke; b. op, birth opening; ent, food canal of redia; eye, eyespots; gast, young redia ; germ, mor, early stages in formation of .the embryo liver-fluke ; int, intestine of larval liver-fluke ; ces, oesophagus ; or. su, oral sucker; pap, head papilla of ciliated larva, A; ph, pharynx; proc, processes of redia; vent, su, ventral sucker. After Thomas. animal, the embryos attach themselves to the food canal of their host and form, by rapid growth, a long chain of seg- ments, each of which is full of germs. The chain, or NEREIS AND ITS ALLIES 15' FIG. 147. — Tsenia solium, the human tapeworm. Entire specimen, about natural size. Cap, head. After Leuckart. 158 ZOOLOGY utape," absorbs fluid food, which soaks through its body wall. As the segments at the older end of the animal mature, they are set free and pass out of the alimentary tract, to be picked up, perchance, in the food of an herb- ivorous animal or else to perish. The economic importance of parasitic worms is very great. Thus, although no great epidemics of the flukes have occurred in this coun- try, a million sheep are annually lost by this para- site in Great Britain ; and in 1879 and 1880 it was estimated that three million sheep died annually in England alone of this parasite. In Buenos Ayres, during 1882, a million sheep died of fluke disease. By great care in prevent- ing infection, especially during damp seasons, we may be able to prevent FIG. 148.— Cerebratulus, a cream-colored any SUch disaster in this nemertean. Head end at upper part of , . figure; mouth turned toward observer, C lWV" proboscis retracted. Instantaneous The group of Nemertini photograph of living worm by W.H.C. P. . ni. i , .-• n , is allied to the flat worms. It includes chiefly marine animals, of somewhat flattened form and great length, even as great as thirty metres. They protrude a long, slender proboscis. These worms are especially abundant in the sand of the seashore, although land nemerteans occur. Cerebratulus (Fig. 148) is a common form from the east coast. APPENDIX TO CHAPTER X APPENDIX TO CHAPTER X 159 i KEY TO THE MORE IMPORTANT FAMILIES OF POLYCH^TA a\. Head distinct from trunk ; proboscis protrusible [wandering Polychseta]. bi. With broad dorsal scales . ; . &2- No scales ; only one mouth-segment. d. Cirri not leaf-like ; body long and not flattened. d\. Head not segmented. ci. Jaws composed of many pieces . 62- Two powerful jaws . cephalic disc. Drawn to various scales. A, Hammea; B, Sca- few Calcareous grains. phander; C, Aplustrum; I), Aphysia; An exactly similar series ^ Philine' From Cooke' "Mollus^-" in the degeneration of the shell is found in certain Opistho- branchs, illustrated in Fig. 149. The beginnings of this process of covering the shell are seen in many gastropods in which the mantle edges may protrude beyond the lips of the aperture, and are folded back over the outer surface of the shell. A more developed condition is seen in species like Aplysia, in which the mantle is permanently reflected.1 In Limax the reflected edges of the mantle i Fig. 149a. 164 ZOOLOGY have permanently grown together. The reflection of the mantle seems to he of advantage by affording additional protection to the visceral mass. But after the complete over- growth of the mantle the shell seems to be useless, and con- sequently degenerates. The Pulmonata are either terrestrial, like the slug, or aquatic. Of the terrestrial Fia. 150. -Shell of iielix alboia- pulmonates other than the bris, a cQmmon forest snail. Nat. , s\Ucr the most important are size. Photo, by W. H. C. P. ., , , , TT T \ the snails of the genus Helix.1 Helix2 is noteworthy, because it is richer in species than any other inolluscan genus, since it contains over three thousand species. The distribution of the genus is world- wide. In North America the snails are most abundant in limestone regions, consequently they are more numerous in individuals in the South and West than in granitic New England. One of the most interesting species is Helix nemoralis, a European form, which has been intro- duced into our country at Burlington, New Jersey, and Lexington, Virginia. At these places it has multiplied so rapidly, and varied to such a degree, that three hundred and eighty-five varieties have been enumerated from an area, at Lexington, not over one thousand feet in extent in its greatest diameter3 (Fig. 151). Any species of Helix collected in large numbers is apt to show abnor- malities in the number of tentacles and of eyes upon the 1 £Xi£, a turning round, as in spire of snail shell. 2 Fig. 150. 3 See paper by Professor J. L. Howe, in American Naturalist, Decem- ber, 1898. THE SLTG AND ITS ALLIES 165 tentacles. Besides Helix, a very abundant cosmopolitan land pulmonate is Pupa.1 Being of small size, it is, how- * FKJ. 151. — Helix nsmaralix, from Lexington, Va., collected by Professor J. L. Howe, showing variation in stripes. Upper line, first figure, normal form, 5 stripes ; other figures of first and second lines show reduction of stripes ; third line shows broader (and fewer) stripes (the last figure is very dark and is poorly reproduced). The shells in the lowest line show more than five stripes. From a photograph ; reduced one-half. ever, less commonly known. It is found in woods under leaves or in old stumps and decaying logs, where it feeds. The shell is many times whorled, and has a blunt apex. Intermediate between the terrestrial and aquatic pulmonates is the family Auriculidte, the members of which live on the seashore, in salt marshes or on rocks where they may even be immersed in brackish water 1 A little girl or doll. FIG. 152. — Me- lampus,the salt- marsh snail. Nat. size. Photo, by \V. H. C. P. 166 ZOOLOGY at high tides. One of the commonest forms is Melampus (Fig. 152), found among the roots of marsh grass. Of the aquatic pulmonates three genera are common and easily distinguishable. Limnaea,1 the '" pond snail," is com- mon in ditches and muddy or stagnant ponds. Its shell runs up into a sharp spire, and is right-handed, i.e. hold- ing the shell so that its aperture is next the observer and below, the aperture is at the right (Fig. 153). Limnsea crawls over the bottom, up the stalks of aquatic plants, and on the sur- FIG. 153. -Left, Physa hetcro- faCG film °f Water' During stropha, the left-handed pond drought it burrows into the snail. Right, Limnaea. the right- i i i ,-, P handed pond snail, with the lliud> aild cl°SeS the aperture of apex eroded off as is usually the the shell . case in adult shells. Nat. size. -r»i_ o i Photo.byW.H.c.P. Pnysa^ has a smaller, rela- tively stouter shell than Lim- nsea, and one whose coil is left-handed (Fig. 153). It lives in even the smaller ponds and brooks, and may be easily reared in aquaria. It feeds freely upon any kind of vegetable matter. Physa heterostropha is the common species of the United States (Fig. 153, left). Planorbis 3 is coiled in one plane like a watch spring.4 It lives in a similar habitat with Physa. A great many species are distinguished which vary con- siderably in size. Snails of this genus likewise are easily kept in the aquarium, and lay numerous FIG. 154.— Planorbis, the flat-coiled pond snail. Nat. size. Photo.byW.H.c.P. 1 From \Lfjivij, a marsh. 2 <£0. With proper hinge, often distinctly toothed and with hinge ligament or pad. Ci. Hinge with many small cardinal teeth in each valve . „ ... Co. Hinge of not over 4 cardinal teeth in each valve. di. Shells equivalve. e\. Two or more times as long as high, gaping more or less at ends. /i. Length 3 to 6 times height ; epidermis polished ; um- bones not over one-quar- ter from anterior end . Solenidce (Kazor Clams) Pholadidw Teredidcv (Shipworms) Ledidw (Ex. Yoldia) APPENDIX TO CHAPTER XII 189 /2. Length about 3 times height ; umbones central, Psammobiidce /3. Length less than 3 times height ; surface covered with radial ridges, chalky white, umbones near an- terior end . . . Petricolidce /4. Length about 2 times height; epidermis polished, with notched border extending beyond the edge of the thin shell, Solemyidce /4. Shell with thick black epidermis ; external liga- ment prominent and on shorter end of the shell, Saxicavidce Length less than twice height, /i. Shell somewhat triangular, with internal cartilage between deep triangular pits, similar in each valve f.2. Shell thin,rounded in front, narrowed and gaping be- hind, cartilage pit shal- low; external ligament short . . Shells inequivalve. e\. Length and height about equal, e^ Length decidedly greater than height. /i. Over 25 mm. long ; right valve nearly flat ; whole shell compressed to one- sixth length . . . /2. Over 50 mm. long ; slightly inequivalve ; no external ligament; internal car- tilage on spoon-shaped process of left valve Mactridce (Hen Clams) Semelidw Pandoridce Myidw (Soft-shelled Clftins) 190 ZOOLOGY /3. Shell under 18 mm.; promi- nent external ligament, «2. Shell not at all gaping. b\. With not over 3 cardinal teeth in each valve. ci. Valves equal in size, curvature, and markings. d\. Anterior muscular impression very small, hinder large; shell elongated, mussel-shaped ; umbo at or near posterior end .... l, round about ; ofy><£, tail. 2 sol, sun ; aster, star. 6 Scaled (squama, a scale). 8 ^Se/ca, eleven. 7 00is, snake ; 0o\/s, scale. 4 00ts, serpent ; ovpd, tail. THE STARFISH AND ITS ALLIES 199 animals live in crevices of the rock, and being of rather small size, are not commonly seen. At the base of the arms, on the right and left, are a pair of slits, which form the exits from pouches into which the reproductive glands open. In certain species the pouches are used for brood- ing the young. The basket-fish occur in Northeastern FIG. 185. — Strongylocentrotus, the Eastern green sea-urchin, with tube feet extended. From " Standard Natural History." waters, from low tide to one hundred fathoms, and are often brought up by fishermen, to whose lines they have a habit of clinging. The branching of the arms enables the animal to hold its prey, which consists of shrimp and fish. The Echinoids, or sea-urchins, may be regarded as star- fishes in which the arms have shortened and the disk en- larged so as to fill up the interspaces, and make a solid, 200 ZOOLOGY nearly spherical form. The sea-urchins eat various small animals, and get food also from small bits of organic matter in the mud which they swallow. They live more concealed than the starfish, for some burrow in the mud and others — such as our green sea-urchin of the Maine coast (Fig. 185) — grind out pockets in the rocks by means of their spines. Others cover themselves with seaweed, and thus become inconspicuous. Besides the green sea-urchin, FIG. 186. — Arbacia, the Eastern black sea-urchin. Tube feet retracted. Nat. size. Photo, by W. H. C. P. which is found north of Cape Cod, we have a black sea- urchin (Arbacia, Fig. 186), which extends south as far as North Carolina. We have on the east coast also two kinds of flat sea-urchins (sand-dollars), which live in the sand from low water to one hundred fathoms. Their spines are small and silky (Fig. 187). Some sea-urchins lose their strictly radial form and become bilateral, having a pointed anterior end (Fig. 188). THE STARFISH AND ITS ALLIES 201 The Holothurians 1 may be likened to soft-skinned sea- urchins, with the body drawn out to the form of a cucum- FIG. 187. — Echinarachnius paruia, the sand dollar. Spines removed from left side. Nat. size. Photo, by W. H. C. P. FIG. 188. — Clypeaster, a bi- lateral sea-urchin from the West Indies. Spines partially removed and surface rubbed in patches. Reduced photo. ber, or even of a worm. The calcareous skeleton is reduced to small plates embedded in the skin. The mouth is sur- rounded by a circle of tentacles. The ambulacral feet are sometimes absent. The Holothurians live in sand and mud, often deeply buried, and feed on small marine animals or the decaying particles mingled with the mud which they devour. They are of considerable economic importance. The members of one genus (Holothuria) is taken in great numbers on the coral reefs of the Pacific , a sort of water-polyp. FIG. 189. — Caudina, the tailed Holothurian. a, mouth; b, anus. After Selenka. ZOOLOGY FIG. 191. — Metacrinus interruptus. After P. H. Carpenter. FIG. 190. — Synapta inhere us. a, tentacles; b, longitudinal mus- cles; c, alimentary tract. — After Quatrefages. Ocean and the China Sea, where they are com- monly known as " t re- pangs." They are cut open, washed, boiled, dried, and sometimes smoked. They are sold in Chinese ports, and some species are con- sidered by Chinese epi- cureans as great deli- cacies. Several species of Holothurians occur on the Maine coast. A bar- rel-shaped form with a APPENDIX TO CHAPTER XIII 203 sort of tail (Caudina,1 Fig. 189) occurs on the Massa- chusetts coast. A worm-like form, but with a beautifully transparent skin (Synapta,2 Fig. 190), is found in sandy beaches from Massachusetts to New Jersey. The Crinoids,3 or sea-lilies, are familiar as fossils to resi- dents of New York State and the Ohio and Mississippi valleys. The living animals are less often seen, for they are inhabitants of the deep sea. They have a cup-like body, with the mouth at its centre directed upward, and surrounded by tentacles (Fig. 191). The cup is either borne on the end of a long stalk or is unstalked. The former condition is more usual among the fossil species. APPENDIX TO CHAPTER XIII KEY TO THE PRINCIPAL CLASSES OF ECHIXODERMATA a\. Sessile ; mouth turned upward ; body calyx-shaped Crinoidea (Sea-lilies) a«. Not sessile. 61. Body short ; skin hard, containing calcareous plates ; mouth directed downward ; madre- poric plate present. Ci. Body with arms which carry a longitu- dinal series of plates. d\. Arms with ventral furrow . . Asteroidea (Starfish) d%. Arms without ventral furrow . . Ophiuroidea (Serpent stars) 1 cauda, tail. 2 a, a mythological monster, capable of regenerating its head. 6 Green. « Brown. 205 206 ZOOLOGY slowly about in search of food. The tentacles are richly supplied with nettling cells, each of which contains a fluid-filled capsule, in which is coiled a thread-like tube. FIG. 192. — Sycon gelatinosum. A portion slightly magnified : one cylinder (that to the right) bisected longitudinally to show the central stomach cavity opening on the exterior by the osculum, and the position of the incur- rent and radial canals ; the former indicated by the black bands, the latter dotted, ip marks the position of three of the groups of inhalant pores at the outer ends of the incurrent canals; 6, osculum. When stimulated by contact with some foreign body the tentacle closes around it, while from each capsule the lasso-thread rolls out as the finger of a glove is rolled inside out, and discharges the irritating poison through THE HYDRA AND ITS ALLIES 207 the lumen of the thread. If a small animal has been the irritant, it is instantly caught in the thread, paralyzed by the poison, and soon conveyed to the Hydra's mouth. The principal food of Hydra is small worms and the smaller Crustacea, such as Daphnia and Cyclops. FIG. 193. — A colony of Cordylophora lacustris, on a shell of Mytilus. For clearness, a number of the erect branches are cut off at the stolon, a, very young1 shoot without lateral branches; b, young stock with lateral branches but no gonophores ; c, a stock with gonophores on lateral branches ; d, fully grown stock with lateral stems. After Schulze. Fresh-water Cnidaria are of extremely few kinds. Hydra was once regarded as the only instance, but others are now known. One of these, called Cordylo- phora, is found chiefly in brackish water or in fresh water, near the coast. Like many of the marine hydroids, Cordy- 208 ZOOLOGY lophora produces its young in special capsules, called gonophores, which are rudimentary jelly-fishes (Fig. 193). The young become free when they have gained an elon- gated, cylindrical form. There are other fresh-water species which have free jelly-fishes. In this country we have a species, Microhydra l Ryderi, hitherto known only about Philadelphia, whose hydroid stage is extremely small and bears no tentacles. The jelly-fishes are set free during July. Fresh-water jelly-fishes have also been described from Lake Tanganyka, Africa, and from a tank at Regent's Park, London, to which they had doubtless been imported on plants. It is very probable that all fresh-water hydroids which produce jelly-fish have, geo- logically speaking, recently come from the sea. Hydra, however, is probably a long-established fresh-water species. The marine hydroids are, in contrast to the fresh- water ones, very numerous. The Hydrocorallidae 2 are peculiar in that they secrete a great amount of calcareous sub- stance, so that they were formerly regarded as belonging to the typical corals (Scyphozoa). They may be easily distinguished by the absence of radial septse in the cups occupied by the hydroid. Here belong the millepore corals of Florida. The Tubularidae3 include some hydroids of large size, single individuals of Tubularia becoming six inches long. Other species grow on gastropod shells which are occu- pied by hermit-crabs (Figs. 194 and 195). So thickly do they grow that they make a plush-like covering on the upper part of the shell, and they have the curious habit 1 Small Hydra. 2 Combining the qualities of Hydra and the corals. 3 From tubulus, a little tube. THE HYDRA AND ITS ALLIES 209 of building out the lip of the shell so as to enlarge the aperture. They do this in order that the hermit-crab, as it grows larger, shall not be forced to exchange the shell for a larger one, leaving the hydroids on the cast-off shell to roll about on the beach and perish. Of the Campanularidae,1 or bell-hydroids, one of the common representatives is Obelia,2 which may be found at low tide hanging from rocks beneath seaweed, and looking like delicate white threads (Fig. 196). Observed FIG. 194. — Stylactis, a tubularian hydroid, growing on a*snail. Nat. size. Photo, of living animal by W. H. C. P. FIG. 195. — Hydractinia, a tubularian hydroid. «, colony growing on gastro- pod shell inhabited by a hermit-crab ; b, bit of colony enlarged ; dz, modified, tactile, individuals ; s, reproductive individuals ; sp, spines. From Parker and Haswell. campanula, a little bell. 6/3eX6s, a spit. 210 ZOOLOGY under the microscope eacli stem appears as a series of hydrantlis placed in zigzag fashion, one beyond the other. FIG. 196. — Obelia ( ?) , a group of campanularian hydroid colonies. Nat. size. Photo, by W. H. C. P. Another common kind is Sertularia,1 which forms rusty brown threads (Fig. 197). All the hydrantlis of one stem occur in one plane and oppositely. Both tubulariaii and campanularian hydroids may give rise to jelly-fishes. These jelly-fishes are formed as buds on the hydraiith, and after they become able to move of themselves they are FIG. 197. — Sertularia, a small colony. 1.5 nat. size. cut oft from the parent and 1 Derived from serta, garland. THE HYDRA AND ITS ALLIES 211 swim away. The jelly-fishes then give rise to the sexual products and discharge them into the water (Fig. 198). In other cases the jelly-fish is formed but never separated FIG. 198. — Bougainvillea ramosa. A, entire colony, natural size; B, portion of the same magnified; C, immature medusa; dr. c, circular canal; cu, cuticle or perisarc ; ent. cav, enteric cavity ; hyd, polyp or bydranth; hyp, hypostome or manubrium ; med, medusa; mnb, manubrium ; rad. c, radial canal; t, tentacle; v, velum. From Parker's "Biology," after Allman. This is closely allied to the New England B. supercilians. 212 ZOOLOGY from the parent, and the eggs develop in the bud. In still other cases a mere bud, called gonophore, is formed, which becomes full of sexual products without ever ac- quiring resemblance to a jelly-fish. The jelly-fish is the primitive type which has undergone a reduction in some cases to a gonophore. It is an interesting fact that in certain species sometimes jelly-fishes and sometimes gono- phores will be produced. In the Campanularidse the FIG. 199. — Zygodactyla. Reduced. From a drawing by A. A^assiz. gonophores are encased in a cuticular capsule, but in the Tubularidee they are quite naked. There are certain hydromedusae in which the hydroid stage is unknown or known to be lacking. Here belong some jelly-fishes of large size, like Zygodactyla, one of the Trachomedusse of our coast, which may become eight to ten inches in diameter (Fig. 199). Besides these the sea contains many small species, which are easily captured in the net, and which are of extreme beauty and delicacy. Besides the Hydromedusse, the group of Hydrozoa in- cludes the Siphonophora.1 These animals are always colonial and free-swimming, and are among the most 1 ov, animal. 8 Keys to the four classes of Protozoa and to the orders of Infusoria will be found in the Appendix to this Chapter, page 229. 222 THE PAEAMECIUM AND ITS ALLIES 223 held that many of the larger animals, such as eels, bees, and flies, were generated without parents. This was the theory of "spontaneous generation." In time this theory became much more restricted. It was found that the maggots in putrid meat are not generated "spontaneously" out of the meat, but are derived from flies' eggs, and, in their turn, develop into fertile flies. But the idea that Infusoria are formed out of inorganic material continued to be held until much more recently, until Pasteur, Tyn- dall, and others demonstrated that fluids heated to a sufficiently high temperature for a sufficient time, and then, while hot, sealed from contact with air, do not develop Infusoria, no matter how long they may be kept. This method of excluding Infusoria and other minute organisms, especially bacteria, is employed to-day in can- ning meat, vegetables, and fruit. The experiments re- ferred to gave a death-blow to the theory of spontaneous generation, and led to the conclusion that all Infusoria are derived from living germs. Whence the living germs come which enter the water it is not difficult to determine. Many Infusoria can pass into a quiescent " spore " stage in which they may be dried and blown about without loss of life. Dry grass, straw, and other substances contain some of the germs, and others float in the air and fall as dust into the water. Even drinking water may contain here and there an infusorian or its germ. When, therefore, one fills a clean vessel with pure water, and puts hay or dry leaves in it, and lets it stand open to the air in a warm place, the result is pretty sure to ba that germs develop in the mixture. The heat and the organic infusion merely facilitate this development. 224 ZOOLOGY Of all the Infusoria, none is more abundant than Para- mecium. It occurs everywhere, principally in stagnant fresh water, but also in salt water. It lives entirely on vegetable food, and is sure to abound wherever plant matter is undergoing decay. When a culture is once FIG. 207. — Carchesium, a stalked Vorticella. Greatly magnified, photograph of the living animals. From a started from a hay infusion, — which takes one or two weeks, — it will be found to thrive especially on corn-meal. As an example of the Heterotricha, Stentor,1 the trumpet- animalcule, may be mentioned. Stentor is found attached to vegetable debris — sticks, stones, water- weeds, and other objects — occurring in pools, ponds, lakes, and sluggish streams. These things should be gathered and placed in a Greek at Troy, known for his loud voice. THE PARAMECIUM AND ITS ALLIES 225 an aquarium, when the Stentors, if present, will attach themselves to the glass sides of the vessel. The attach- ment of Stentor to objects is not permanent, for it may loose its hold and swim free. When the animal is stained in haematoxylin, the characteristic nucleus, looking like a chain of beads, becomes evident. Vorticella,1 the bell-animalcule, is found in pools or infusions, permanently attached by a long stalk. When the animal is irritated, it contracts its stalk, which twists into a close spiral. Carchesium 2 differs from Vorticella, in forming colonies, so that a number of heads are attached to a central stalk. A colony, when fully expanded, appears like a fine, white mould attached to a submerged object. In both of these types the food consists of small organic particles, which are swept into the gullet by the circlet of cilia placed around the upper end of the body. The Suctoria3 are sessile Infusoria, from whose upper surface numerous remarkable sucking-tentacles arise. By means of these tentacles the animal can hold on to Para- mecia and other free-swimming Infusoria, from which it extracts the body fluids. Some Suctoria are stalked (e.g. Podophora*), while others are unstalked (e.g. Acineta^. They are found most abundantly in standing water, either fresh or salt, and are often attached to other animals, — Bryozoa, entomostracans, and pulmonate mollusks. Of the group Flagellata,6 or lash-animalcules, Euglena7 is a common representative . It is of microscopic size, but occurs in such numbers as often to give a decided green 1 Dim. from vortex, whirlpool. 4 Trofo, foot ; 6pfc, eyebrow. 2 Kapx'/iov, animal, alteration. 228 ZOOLOGY the nucleus, which it is often difficult to make out on the living animal. The whole substance of the Amceba is mobile, so that the internal organs have no fixed relation to one another. Quantities of Amoeba can usually be obtained for study by gathering the mud from the edges of stagnant pools, or by scraping the green growth from flower-pots, and letting these gatherings, covered with a little water, stand in a fairly warm place for two or three weeks. Even the Protozoa bear important relations to man. One species, Amceba coli, has long been known occasion- ally to inhabit the food canal of man, and it is now known that an amoebiform organism (probably one of the Sporo- zoa) is the cause of malarial diseases. Since in one common species 48 hours are required to complete a developmental cycle, the recurrence of the fever every alternate day is explained. It is now demonstrated that at least one of the common agents in infection with malaria is the mosquito, which carries the germs of the malaria parasite from one host to another. Other Sporozoa, of at least one species, are parasitic in the human liver, others attack fish and cause them to die in large numbers; still others cause sickness and death among domesticated animals. The Texas fever among cattle is believed to be caused by an organism1 belonging to this group, the inoculation of the cattle being effected by the cattle-tick. The reproductive capacity of Protozoa is so great that their importance in the world, despite their small size, is not astonishing. One of the early students of Protozoa, Ehrenberg, computed that from one individual of Para- mecium aurelia 268,000,000 might be developed in one 1 Called Piroplasma bigeminnm. APPENDIX TO CHAPTER XV 229 month by the process of division. Apparently the divi- sion cannot go on indefinitely, but from time to time the Paramecia unite temporarily in pairs and undergo an exchange of some of their nuclear matter. This is doubt- less the beginning of what is known in the higher animals as sexual reproduction. APPENDIX TO CHAPTER XV KEY TO THE FOUR CLASSES OF PROTOZOA a\. Without non-retractile appendages. 61. With retractile pseudopodia . . • -. . . Ehizopoda (Ex. Amoeba) Z>2. Without pseudopodia ; covered with an im- perf orate cuticula ; parasites . :. , Sporozoa «2. With non- retractile appendages. 61. No cilia, but with one or more flagella . , Flagellata (Ex. Euglena) &2' With cilia, or sucking tentacles . ,. . Infusoria (Ex. Paramecium) KEY TO THE SUBCLASSES AND ORDERS OF INFUSORIA a\. With vibratile cilia and no sucking tentacles * - CILIATA 61. Body everywhere closely beset with cilia. GI. No adoral zone . . ... » ___ Holotriclia (Ex. Parameciurn) c2. Adoral zone present . • ... Heterotricha (Ex. Stentor) 62- Body only partly ciliated. d. Cilia limited to ventral side . . . . Hypotricha c2. Cilia form a circlet around or at upper edge of animal . . . . Peritricha (Ex. Vorticella) a2. With sucking tentacles . . . . . . SUCTORIA CHAPTER XVI THE SMELT AND ITS ALLIES THE smelt is one of the class of fishes.1 This class com- prises vertebrates that breathe by means of gills and do not use their appendages for walking. The smelts, which belong to the salmon family, are pre- eminently inhabitants of the northern temperate zone, since all but one of the ten genera occur only there.. They are small marine fishes, and although a few are inhabitants of the deep sea, most live near the shore, and in the spring ascend rivers to spawn. Some of them have become cut off from descending to the sea and live permanently, as " land-locked " forms, in fresh water. Such " land-locked " individuals are of smaller size than the marine ones. The food of smelts, like that of other Salmonidse, is chiefly animal, consisting of smaller fishes or insects, small crusta- ceans, and mollusks. Smelt are of considerable economic importance, since they share with other members of the salmon family a delicately flavored flesh. Our Atlantic form, Osmerus 2 mordax? which ranges from Delaware Bay northward, is caught most abundantly in Maine. The total Atlantic 1 Keys to the principal orders of fishes and the six suborders of the Teleostei will be found at the end of this Chapter, page 252. 2 6, .. § >» 1 | g a i ~- '£ ^ a -5 oT'w ||4 m is " C cr ~ 3 c C^ a^r^ .S £ 5 ^J * " §H ai X2 iT s .2 1^1 -f tf 'r; o •-[. * o a 'Vi c "6 >• 1? & a ^ * ^r « M •g £ ^ ^ 93 •^ ^ s^ the entire 1 >J ^H 3[ h .s 1 ?,-! IIs, g a.g 0) -M <-T G< C ci g cT C • .s | !&1 11^ 5> *** eim's ' \ £ . ^, ^ \ ^ •S jf js3 £ O) o! &, a; L'^.S'S is * * 8 3J d x O 3 S S o f? £ Columbia River that very few salmon are permitted to pass the nets of the canning factories, and consequently THE SMELT AND ITS ALLIES 233 the apparently inexhaustible supply of this fish has been immensely reduced, and the fishery will soon become destroyed. op FIG. 212. — Salmo fario. a. I, adipose lobe of pelvic fin ; an, anus ; c.f, caudal fin ; d. f. 1, first dorsal ; d.f. 2, second dorsal or adipose fin ; 1. 1, lateral line ; op, operculum ; pet. f, pectoral fin ; pv.f, pelvic fin ; v.f, ventral fin. After Jardine. The trout, of which there are a number of kinds on both continents, is commercially much less important than the FIG. 213. — Coregonus, the lake whitefish. Much reduced. From Goode. salmon proper. As a result of overfishing, and the pollu- tion of streams by factories and sewage, this fish is dis- appearing from Eastern waters. 234 ZOOLOGY The whitefish (Coregonus *), of which we possess many species, is exclusively an inhabitant of fresh water.2 Its teeth are almost completely absent, or very small ; it feeds almost exclusively upon small arthropods and mollusks. It is of very great commercial importance, its fisheries being valued at nearly three million dollars a year. Leaving now the Salmonidse, we may briefly consider some of the other more important families of bony fishes. FIG. 214. — Morone americana, the white perch. The fish is searching for food along the bottom of the aquarium, an instinct which it shows in nature also. About one-third nat. size. Photo, of living animal by Dr. R. W. Shufeldt, from " Bull. U. S. Fish Com.," 1899. The darters are spiny-rayed fishes of small size, from four to seventeen centimetres long, brightly colored, and with well-developed pectoral fins. They live in clear streams, half concealed under stones, and are most abundant in the Mississippi drainage basin. 7, the pupil of the eye ; ywvia, angle. 2 Fig. 213. THE SMELT AND ITS ALLIES 235 The perches are a widespread family, represented in this country chiefly by the common yellow perch of the East, the " wall-eyed pike " of the Great Lake region, and the white perch of the Atlantic coast (Fig. 214). These fish have an oblong, compressed body covered with small scales ; they are highly rapacious, and are believed to be FIG. 215. — Eupomatis f/ibboftus, the common sunfish. Two-thirds nat. size. Photo, of living animal by Dr. R. W. Shufeldt, " Bull. U. S. Fish Com.," 1899. destructive to the young of other species of fish. They are esteemed as food, although fortunately not to the extent of annihilation. The sunfishes1 have a percoid form, but have only one dorsal fin instead of two. They live in fresh water, have 1 Fig. 215. 236 ZOOLOGY rapacious habits, are brilliantly colored, and build nests in the sand, which both male and female watch over and defend with courage. Some species living in the Great Lakes are known as black bass or rock bass. The small New England species, with the brilliant red edge to the operculum, is called pumpkin-seed. The toadfishes (Fig. 216) are represented in our faunas by a common species which lives under stones in harbors and attaches its eggs to the under side of stones. It is a vigorous fighter. The sculpin (Fig. 217) is closely related to the toadfish. Like the latter it has a broad head and nearly scaleless body. The pectorals are large, and the two dorsals extend along the greater part of the back. Allied to the foregoing is the rock eel (Fig. 218), which is sometimes brought up in the seine from a depth of 8 to 10 fathoms. FIG. 216. — Batrachus tau, the toadfish. Dorsal view. Two-thirds nat. size. Photo, by W. H. C. P. FIG. 217. — Acanthocottus, the little sculpin. Two-thirds nat. size. Photo, by W. H. C. P. The silversides are especially abundant along our At- lantic coast. They have an elongated, somewhat com- THE SMELT AND ITS ALLIES 237 pressed body, and a broad, bright silvery band on the sides, against a greenish general body color. The dorsal FIG. 218. — Pholis, the rock eel. Right side. Nat. size. Photo, by W. H. C. P. spines are slender. The fish swim near shore, in dense schools. One species on the Californian coast is known as a " smelt," and is a good food fish. FIG. 219. — Gasterosteus punyitius, the nine-spined stickleback; male (above) and female near the nest in rushes. The female is about to deposit its eggs in the nest. 238 ZOOLOGY The sticklebacks are small, elongated fishes, having an extremely slender tail and a large mouth. The dorsal fin is preceded by two or more large isolated spines. The fishes live in either fresh or brackish water. In some of FIG. 220. — Gastsrosteus bispinoxns, the two-spined stickleback. Above, nest with eggs, and male entering. Below, male depositing its mil on the eggs. Figs. 219 and 220 are reproductions of water-color paintings in the Museum of Comparative Zoology at Harvard College. the species the male builds an elaborate nest from bits of aquatic plants, firmly united by a special mucilaginous secretion. The nest, which is built among the plants of the stream, consists of a short cylinder, through the hori- THE SMELT AND ITS ALLIES 239 zontal cavity of which the fish can lie while it deposits its eggs. The male is polygamous, and guards the single nest, which receives the eggs from various females (Figs. 219, 220). The codfishes, among the most important of food fishes, are characterized by having ventral fins without spines, and articulated fin-rays, well-developed caudal fin, isocercal tail, and barbel 011 chin. Our common codfish (Fig. 221) FIG. 221. — Gadus morrhua, the codfish. About one-seventh nat. size. After Storer. occurs over the whole of the North Atlantic ; but the most important fishing localities are the banks near New- foundland, especially Grand Bank. The flatfishes are peculiar among fishes in that they have the habit in the adult stage of lying on one side. In consequence the under eye migrates to the upper side, so that both eyes come to lie on the same side of the body. The mouth also tends to become unsymmetrical. The flatfish, .consequently, illustrates well the principles of self- adaptation to a peculiar environment. The catfishes are distinguished by the possession of four to eight long barbels around the mouth, and by the 240 ZOOLOGY absence of scales on the body. They are characteristic of South America, but there are a large number of species in the United States, mostly found in the Mississippi valley EVS \ v\ FIG. 222. — One of the flatfishes, seen from the upper side. Two-thirds nat. size. Photo, by W. H. C. P. and the Great Lakes, inhabiting deep or sluggish waters, and living in the mud. The common New England FIG. 223. — Ameiurus nebulosus, the catfish. About one-half nat. size. Photo, of living animal by Dr. R. W. Shufeldt, " Bull. U. S. Fish Com.," 1899. THE KNELT ANT) ITS ALLIES 241 species is Ameiurus1 catus? the bull-head or horn-pout.3 It was with reference to this species that Thoreau wrote that they are "a bloodthirsty and bullying race of rangers, inhabiting the river-bottoms, with ever a lance at rest and ready to do battle with their nearest neighbor." The stiff, jagged rays of the pectoral fins can make severe wounds. The great catfish of the Mississippi River, which may weigh up to 90 kilogrammes, is known as Ameiurus lacustris.^ This, as well as most other species of catfish, is much prized as food. FIG. 224. —The brook sucker. After Goode. The suckers are characteristic North American fish, abundant in every creek, and consequently known to every lover of woods and brooks. Characteristic is the form of lips, which are thick and drawn down at the corners.5 They are rather sluggish fishes, and feed on small aquatic insects and suck up mud. They are not generally esteemed as food, inasmuch as their flesh is coarse and very full of bones. In the Mississippi valley, however, they are so abundant and large that they are of some commercial importance. , not curtailed. 2 Cat. 8 Fig. 223. 4 Living in lakes. 5 Fig. 224. R 242 ZOOLOGY The term "minnow" is applied to two distinct families of small fish. One of these is also known as " killifish." The killifish have a broad head covered with scales, and have well-developed teeth in the mouth. They occur in schools in shallow water on the shore, and ascend streams to their source. They are carnivorous, and feed at the surface. In one species from the Southern coast, Heterandria 1 for- niosaf the male is only about two centimetres long, and is the smallest known vertebrate. Our commonest species on FIG. 225. — Fundulus heteroclitus, a killifish or shore minnow. Nat. size. Photo, by W. H. C. P. the shore, or in brackish water, is Fundulus 3 heteroclitus 4 (Fig. 225). The minnows of the other family have a nar- row head without scales, and with no teeth in the mouth. They occur exclusively in fresh water, and are known as "shiners.''' The "goldfish" is related to this group. The pike and pickerel (Esox5) are roughly cylindrical fishes, with large mouth, elongated, depressed jaws, and strong, hooked teeth.6 They are large, voracious, fresh- water fishes, confined, with the exception of a single species, to the United States. The " muskallunge " of the Great s, different ; dnfa, dj>fy>6s, man, male. 2 Comely. 3 fundus, bottom. 4 ere^/cXi-ros, irregular or unusual. 5 fool-, a fish living in the Rhine, mentioned by Pliny. 6 Fig. 226. THE SMELT ANT) ITS ALLIES 243 Lakes reaches a length of two metres. It is, fortunately, somewhat rare, otherwise there would be few other in- habitants of our large streams. FIG. 22(>. — Lucius luci'tis, the pike. About one-fifth nat. size. Photo, of living animal by Dr. R. W. Shufeldt, " Bull. U. S. Fish Com.," 1899. The shad is a representative of a family — the herring family — which has played an important part in the civiliza- tion of Europe. There is an old adage in Holland to the FIG. 227. — Alosa sapidissima, the shad. After Goode. effect that Amsterdam is built on herring-bones ; and the Emperor Charles V. said that the herring brought greater wealth to 'the Netherlands than did America to Spain. Our common shad, Alosa l sapidissima,2 ranges from New- 1 From Saxon allis, old name of the European shad. 2 Most delicious. 244 ZOOLOGY foundland to Florida.1 Next to the Pacific salmon and cod, it is commercially our most important fish, for the catch of Atlantic shad for 1896 exceeded one and a half million dollars. The Pacific coast has been successfully stocked with shad from the Atlantic. The Atlantic shad, like the salmon, migrate up streams to deposit their eggs. The alewives have the same habit. The herring, on the contrary, spawn in the sea. As the common name, allied to the German Heer, an army, implies, they travel in great schools. The menhaden, which also occur in great schools, have of late years been destroyed in vast numbers to make fertilizers. The eels are easily distinguished by their serpentine form, the absence of ventral fins, the long dorsal fin, and the rudimentary or absent scales. These fish occur all along our coast and ascend streams. During the day they lie hidden in mud and at night they feed, their principal prey being small aquatic animals, the young of other fish, and shrimps and crayfishes during the moulting period. On account of the narrowness of the gill-opening, they may live for some time out of water in a moist place. The reproduction of the eel was long a mystery. All sorts of creatures have in past times been supposed to produce them, ranging from the gods to water-beetles. They have even been thought to be generated from slime. We now know, however, that there are both male and female indi- viduals ; that the males live chiefly, but not exclusively, in the sea ; that reproduction occurs chiefly in the sea ; and that the young females come from the sea and pass up the rivers during the spring. The pipe-fishes and their allies (Lophobraiichii) include iFi. 227. THE SMELT AND ITS ALLIES 245 a number of aberrant forms. Some of these are greatly elongated, like the pipe-fish proper (Fig. 228) ; others are shorter and stouter, like the " sea-horse." All have an FIG. 228. — Siphostomafuscwn, the pipe-fish. Nat. size. Photo, by W. H. C. P. elongated snout, and usually a long, slender tail. The body is encased in bony plates, and the male is often pro- vided with a brood-pouch, in which the developing young are carried. Besides the bony fishes, which we have just considered in detail, there are various other classes of fish. FIG. 229. — Petromyzon, the lamprey. One-fourth nat. size. After Goode. The Cyclostomi, or lamprey eels, are the only parasitic vertebrates. In the adult stage they either live attached 246 ZOOLOGY to the outside of other fishes, sucking their blood, or else they may penetrate into the body cavity. They do not bite, because they have 110 lower jaw, and are known as " round- mouthed" eels.1 Lam- preys are found in the seas and in the rivers of the temperate zones. They occur on our Eastern coast and ascend rivers ; others live in the lakes of New York, in the Great Lakes, and in the Missis- sippi valley. In Europe £ > they are much esteemed as food. The Selachians include the sharks and rays, all inhabitants, of the sea. They may be distin- guished from the bony fishes by the rough skin, beset with spines, and by the cartilaginous skele- ton. We have a num- ber of sharks on our Northeastern coast, of which the dogfishes and the sand-shark are the i Fig. 229. lill THE SMELT AND ITS ALLIES 247 commonest (Fig. 230). They are all carnivorous animals and powerful swimmers. They feed on the larger Crus- tacea and fish. The living Ganoidei are a remnant of a very extensive group which existed in geological times. North America is especially rich in existing representatives of this group, as of several other old groups, such as the turtles, tailed amphibians, and the king-crab. Of the five families of ganoids, fonr are represented in this country. In the following four paragraphs we shall consider a type of each of the native families. The sturgeons have five rows of bony scales on the trunk and four barbels on the head.1 They occur both FIG. 231. — Acipenser, the sturgeon. One-sixteenth nat. size. After Goode. in the sea and in the Great Lakes and the rivers of the Central States. Although of large size, they feed for the most part on small aquatic animals, such as worms, insect larvae, and small fish. The flesh of some species is much used as food ; the eggs taken from the ovaries (roe) con- stitute a delicacy known as "caviare." The spoonbill, Avhich has an elongated, flattened snout and is almost without scales, is a large fish found in the Mississippi River. It is also called "paddle-fish" or " duck-bill catfish." It becomes two metres long and seeks small animals in the mud, which it stirs up with its snout. 1 Fig. 231. 248 ZOOLOGY The garpikes are known by their long snout (Fig 232). They are completely clad in an enamel coat of mail. They are of sluggish habits, but voracious, and their flesh is FIG. 232. — Lepidosteus, the garpike. One-eighth iiat. size. After Tenney. valueless as food. One species is found in China, the others in the rivers of North America. The bowfin (Amia1) occurs in the rivers and lakes of the United States. It has a short body, a blunt head, and FIG. 233. — Amia calva, the bowfin. One-sixth nat. size. From Leunis. a long, dorsal fin (Fig. 233). It is the sole survivor of a formerly large family. The Dipnoi 2 include only three rare foreign forms, which seem to form a transition between fishes and the higher groups, for some of them have lungs in addition to gills. From some such lunged fishes must the amphibia have arisen (Fig. 234). Ancestry of Vertebrates. — The fishes, amphibia, reptiles, birds, and mammals, which are considered in this and the following chapters, constitute together the group of verte- brata, or backboned animals. All the animals treated of , ancient name of a fish. 2 5£s, twice ; TTVOT?, breath. TILE SMELT AND ITS ALLIES 249 250 ZOOLOGY FIG. 236. — Ciona, a simple tunicate, o, mouth ; at, open- ing of atrium, or exhalant opening; st, stolon. After Leuckart and Nitche's dia- grams. FIG. 238. — Balanoglossus, the acorn- tongued worm. The proboscis at the anterior end is at the top of the figure (partly outside) ; behind it is an orange-colored collar ; then follows the long, brown-red trunk. Nat. size. Photo, of living animal by W. H. C. P. FIG. 237. — Botryllus, a compound tunicate. Nat. size. Photo, by W. H. C. P. THE SMELT AND ITS ALLIES 251 in earlier chapters are invertebrates. Between verte- brates and invertebrates and connecting the fishes with more worm-like ancestors, is the lancelet or Amphioxus.1 This slender, rod-like animal is only 50 to 70 milli- metres long. Its internal structure shows its relationship with vertebrates ; it has the forerunner of a vertebral column and a spiral nerve and it has also gill slits like a fish, but it has no skeleton.2 It lives in sandy seashores in temperate and tropical zones. On our Eastern coast it is found from Chesapeake Bay south. It stands embedded in the sand, the tentacle-fringed mouth projecting above the surface. It feeds on minute organisms of all sorts. Of the invertebrate groups, that of Tunicata lies nearest to the stem from which the vertebrates arose. The adult animals, however, are very different from vertebrates, for they are attached (Fig- 236), and sometimes even form colonies (Fig. 237). But the young animals are much like tadpoles of frogs ; not merely superficially, but in their structure. Going further back it seems clear that vertebrates have developed out of the worms. A very worm-like animal, which seems to foreshadow the verte- brates in having gill slits and the forerunner of a back- bone, is common in our sandy beaches. This is Balano- glossus3 — the acorn-tongued worm, so called from the shape of its proboscis (Fig. 238). 1 a/j.i, both [ends] ; 6£tfs, sharp pointed. 2 Fig. 235. 3 pdXavos, acorn ; 7\w<7(ra, tongue. 252 ZOOLOGY APPENDIX TO CHAPTER XVI KEY TO THE PRINCIPAL ORDERS OF FISHES «i. Without skull, paired fins, or heart ; blood color- less Acrania (Ex. Amphioxus) ao. With skull, heart, and red blood [Craniota]. 61. Without lower jaw or paired fins 62- With lower jaw and paired fins [Gnatho- stomi]. Ci. Intestine with spiral valve. d\. Without an operculum covering the gill openings ; scales toothed $>. Operculate ; skin with enamelled scales. e\. Breathing by means of gills only . . . . . eg. Breathing by both gills and a lung .''- -, ...• . . • . eg. Intestine without spiral valve ; skele- ton bony . . . . .'.'.' Cyclostomi (Lamprey eels) Selachii (Sharks and rays) Ganoidei (Ganoid fishes) Dipnoi (Mud fishes) Teleostei (Bony Fishes) KEY "TO THE SIX SUBORDERS OF TELEOSTEI Gills comb-like. b\. Intermaxillaries and maxillaries movable on each other. Ci. Dorsal fin, anal fin, and ventral fin spinous anteriorly. d\. Pharyngeal bones distinct . . Acanthopteri (Perches, darters, sunfishes, toadfishes, sculpins, silversides, sticklebacks) d2. Pharyngeal bones united . . Pharyngognathi c2. Dorsal, anal, and ventral fins without spines. APPENDIX TO CHAPTER XVI 253 d\. Ventral fin, when present, placed on throat or breast ; air-bladder without air tube . . . Anacanthini (Codfishes, flatfishes) do. Ventral fin, when present, placed ventrally ; air-bladder with air- tube Physostomi (Smelt, trouts, whitefishes, catfishes, .suckers, minnows, shads, eels) &2. Intermaxillaries and maxillaries united with each other and with skull . . . Plectognathi Gills small, tuft-like ; body covered with bony plates ........ Lophobranchii (Pipe-fishes) CHAPTER XVII THE NEWT AND ITS ALLIES THE newts belong to the class Amphibia,1 or, as it is also called, Batrachia, characterized by the fact that, while they have no rayed fins like fishes, but legs instead, they have functional gills during at least a part of their free life. The eggs, which are laid in water, are without a hard shell. The little newt Diemyctylus virldescens 2 is found in New England and westward to the Mississippi valley. During different stages of development it assumes widely different habits. The eggs are laid during the spring in water, where they hatch after three to five weeks and appear as olive-colored tadpoles with external gills. At this time they have an exclusively animal diet, feeding on minute Crustacea, larval insects, snails, and aquatic worms. In August the gills and tail-fill become absorbed, and the transformed animal takes to land and lives under stones at some distance, it may be, from water. At this time it has a vermilion color,3 and feeds on spiders, insects, and earthworms. After two or three years the newt assumes a 1 Keys to the Orders of Amphibia and to the families of Urodela will be found in the Appendix to this Chapter, page 266. 2 The newt of the Pacific coast is D. torosus. 8 The color and habitat of the terrestrial young Diemyctylus are so different from the fully matured aquatic form that the two were formerly regarded as distinct species. 254 THE NEWT AND ITS ALLIES 255 brown color, and eventually the olive-green or viridescent color of the adult. It then takes to the water and is found especially in springs, and in ponds and brooks fed by springs. It now subsists on various aquatic worms, crustaceans, insects, and mollusks. The newt gains oxygen for respiration by swallowing air mixed with water.1 Distribution. — The Amphibia live chiefly in tropical and subtropical countries, although a number of them belong to the colder parts of the temperate zone. There are no strictly polar species, although one species of frog extends from Massachusetts north to Alaska. The Gymnophiona2 are confined to tropical countries and are most abundant in South America. They live, like earthworms, in the ground and have more or less rudimentary eyes. The Urodela are confined in their distribution to the Northern Hemisphere (excepting that two or three species extend along the Andes south of the equator). North America is especially rich, both in species and individuals, of Uro- dela. The Anura, or toads and frogs, are found in all parts of the world, especially in South America and Australia. Families of Urodela. — Of the American Urodela,3 the Sirenidae include the Siren,4 or mud-eel, of the Southern States. This species becomes 60 centimetres long, and is of a dark lead color (Fig. 239). It is needlessly feared by the negro rice cultivators, who slaughter it in great numbers. 1 Newts may be captured by sweeping with a net the muddy bottoms of small, spring-fed pools. They can be kept for months in an aquarium, where they should be fed thrice a week with earthworms or freshly chopped beef. 2 From yv/mv6s, naked ; 60iW, a fabulous, snake-like animal. 3 ou/sd, tail ; SiJXos, conspicuous. 4 A mythological creature. 256 ZOOLOGY THE NEWT ANT) ITS ALLIES 257 The Proteidae l include our Necturus, commonly known as mud-puppy or water-dog, which is found from the Hudson River to the Mississippi valley, and is very abundant in the Great Lakes. Its external gills are very large, and red with the blood flowing in them. It feeds 011 small water-animals. In April or May it lays eggs about the size of a pea. A curiously modified form of Necturus occurs in caves (Fig. 240). Another member of this family is the cave " olm " of western Austria. The Amphiumidae2 include only the Congo snake of the Carolinas and Gulf States. This black, snake-like Urodelian is about a metre long, and lives in bayous and muddy ditches (Fig. 241). It has the entirely undeserved reputation of being injurious. The Cryptobranchidae 3 include the so-called "hell- bender" of the Ohio valley and south.4 It is a very voracious scavenger of the water, and bites the hook fiercely. It is noted for its great tenacity of life under unfavorable conditions. The only other living repre- sentative of this family is the Japanese giant salamander, which becomes three metres long. The Amblystomidae 5 include some twenty-five species belonging to five genera, four of which occur in northern and eastern Asia, and the fifth, Amblystorna, is confined to the United States and Mexico, excepting one species, occurring in Siam. The common species of New England and the Central States is known as the Spotted Sala- 1 IIpoTerfs, a sea-god possessed of the power of changing himself into different shapes. 2 Probably a modification of a native name. 3 /cpu7rr6s, hidden ; ppdyxiOV> gill- 4 Fig. 242. 5 From d/ijSXtfs, blunt ; 6s, bond ; yvd6os, jaw. 3 trTT^Xcuoj', cavern ; fyirTjs, a crawler. 260 ZOOLOGY purplish spots on the sides. Both Spelerpes and Desmo- gnathus live in and about running brooks, under stones and fallen logs. Their eggs are attached to the under surface of submerged stones. The adults are easy to keep in confinement in a moist fernery. They may be obtained out of doors all the year round, excepting during the time of deep snow. There are four species of Spelerpes and three species of Desmognathus in the northern United States. Metamorphosis. — As we have seen, all Amphibia have gills while young, but some lose them before maturity while others retain them permanently. Those species which retain the gills pass their whole life in water ; the others may live on the land. The loss of gills is asso- ciated with the assumption of a land life. In the Ambly- stoma we have species which are curiously intermediate between the two classes in that they may retain their gills, tail-fins, and other structures adapted to aquatic life,1 even to the time of reproduction ; or they may lose their gills and tail-fins. The first result follows if they are pre- vented from coming on land ; the second, if they are forced to leave the water. The capacity of the Mexican Axolotl for either becoming an adult or remaining a larva was first shown by some experiments of the German naturalist Weismann and a pupil of his. It will be seen that when forced to live in the water Axolotl retains permanently a larval condition ; and one would never know that in this larval condition the animal is not adult were it not for the accident of its sometimes becoming adult. It is quite possible that all of the Urodela which retain their gills throughout life may formerly have had a gill-less adult stage which is now lost. 1 Compare Fig. 243. THE NEWT AND ITS ALLIES 261 Early Development of Urodela. — The eggs of Urodela are deposited in a gelatinous mass in water, and are attached to submerged plants, or to other objects in the FIG. 12 FIG. 13. FIG. 17. FIG. 18. FIG. 19. FIG. 245. — Developmental stages of Spelerpes bilinecitus. Figx. S-'J, neural groove beginning to form; Figs. 10, 11, neural groove closed; Figs. 12, i;>, head beginning to form; Figx. 14-lf>, tail formed, yolk absorbing; Fig. 17, embryo capable of moving in egg membrane ; Fig. IS, embryo just able to swim ; Fig. W, three days after hatching. The letters indicate the successive stages. After H. H. Wilder, from "The American Naturalist." water, either singly or in masses, according to the species. The eggs contain much yolk ; consequently the cleavage is partial, and the embryo seems to develop on a small part 262 ZOOLOGY only of the yolk and for some time after hatching the yolk mass hangs as a lump on the under side of the embryo. Very early a deep groove, bounded by a pair of folds, arises on the edge. This groove is large in front (Fig. 245, &). It forms the beginning of the brain and spinal cord. The feathery gills and the beginnings of the appendages FIG. 246. — Pipa americana. Female with young in pits on its back. next sprout out, while the trunk continues to elongate and assume the form of a young salamander (Fig. 245). Families of Anura. — Of the Anura there are eight or ten times as many species as there are of the Urodela. They are distributed into nearly a score of families. Of THE NEWT AND ITS ALLIES 263 these a few of the more interesting deserve to be men- tioned. FIG. 247. — Section through skin of back of Pip a, americana, showing develop- ing embryos. Much enlarged. The Pipidae include the South American Pipa, note- worthy because of the habit which the female has of brooding its young in pits of the skin on her back (Figs. 246, 247). FIG. 248. — Nodelphys, brooding tree-frog, female, from Venezuela. In the hinder part of the trunk the opening to the brood-pouch is seen. From a water- color painting at the Museum of Comparative Zoology at Harvard College. The Hylidae, or tree-toads, include various arboreal species in which the ends of the fingers are modified for 264 ZOOLOGY holding on to objects by suction. Of these there are over one hundred and seventy species, especially abundant in tropical America. In one member of this family the female has a pouch on the back, opening in the hinder third of the trunk (Fig. 248). In this the young are FIG. 249. — Bufo lentiginosus, the American toad. Photo, of living animal, resting on the ground, by W. H. C. P. brooded. The most common tree-toad of the northern United States extends from Canada to Florida, and west to Kansas. It is variable in color, being green or brown, according to the color of the background, leaf, or bark, on which it is resting. It has a loud, coarse trill, often THE NEWT AND ITS ALLIES 265 erroneously regarded as a weather sign. The eggs are laid in small bunches in shallow water. The Bufonidae include the common toads which occur all over the world. Our Eastern toad1 inhabits nearly all the United States east of the Rocky Mountains.2 It is crepuscular in its habits, and feeds chiefly on insects and worms. The eggs are deposited in two long, parallel strings of albumen, which lie coiled at the bottoms of* FIG. 250. — Rana damttano, green frog. Nat. size. Photo, of living animal by W. H. C. P. ponds, hatch out in May, and metamorphose about a month later. The Ranidae are almost confined to the Northern Hemi- sphere and the East Indies. In the northern United States there are some eight species, of which the commonest are: the leopard-frog, of green color, with irregular black blotches edged with whitish ; the pickerel-frog, light brown, with two rows of oblong square brown blotches 1 Bufo lentiginosns. 2 Fig. 249. 266 ZOOLOGY on the back ; the wood-frog, living in damp woods, pale reddish brown, with a brown band on the side of the head ; the green frog, of uniform bright green to brown color, with numerous small dark spots, and with glandular folds (Fig. 250) ; and the bull-frog, of great size, green, with small faint spots 011 the back. APPENDIX TO CHAPTER XVII KEY TO THE ORDERS OF AMPHIBIA a\. Appendages and tail lacking; body worm-like ; skin furrowed transversely „ •.''-. . Gymnopliiona «2- Appendages present. 61. Body elongated ; tail present ; generally 4, but rarely only the 2 anterior appendages present ... . _ „ ' ., .. . ^ Urodela b2- Body short ; in adult condition tailless . - Anura KEY TO THE FAMILIES OF URODELA a\. External gills persistent throughout life ; maxil- lary bone small or wanting. 61. Body eel-like ; hind legs absent ; jaws with horny sheath . . . . . .. Sirenidm b2. Body salamander-like ; hind limbs present ; teeth on jaws . _'*, • • ' -* . .... Proteidcv a2. External gills normally disappearing in adult ; limbs 4 ; maxillaries present. 61. Side of neck with spiracular opening ; no eyelids, ci. Limbs rudimentary .. . . AmphiumidcR c2. Limbs well developed . . . Cryptobmnchidce 60. Side of neck without spiracular opening in adult ; eyelids present. APPENDIX TO CHAPTER XVII 267 Palatine teeth in transverse (or nearly transverse) series. d\. Vertebrae doubly concave. e\. Parasphenoid without teeth ; tongue large ; toes 4-5 63. Parasphenoid with teeth ; tongue small .. do. Vertebrae convex behind only ; tongue moderate ; toes 5 Palatine teeth in 2 longitudinal series, diverging behind . Amblystomidce PlethodontidcK Desmognathidce Pleurodelidat (Ex. Diemyctylus) CHAPTER XVIII THE LIZARD AND ITS ALLIES THE lizards belong to the class of Reptiles,1 which are vertebrates in whose skin horny or bony scales or plates are formed. They constantly breathe by means of lungs, and lay large eggs provided with a tough leathery or calcareous shell. The Sauria, or lizards, constitute a large order charac- teristic of the tropical and subtropical countries and reaching the maximum of its development in South America, while in the northern continents it is relatively poorly represented. Lizards are, as a rule, carnivorous, and since they destroy insects injurious to vegetation, they may be counted as beneficial to man. Anolis 2 is one of the family Iguanidae,3 a large group of lizards characteristic of the Western Hemisphere. The family is known by the thick tongue, by a large scale in the middle of the head in front of the eyes, and by the fact that all four legs are well developed. The genus Anolis contains eighty tropical species. Oar species lives in pine woods from the latitude of Tennessee south to the Gulf and the island of Cuba. Its graceful form and bright colors make it one of the most beautiful of lizards. It 1 A key to the four orders of Reptiles will be found in the Appendix to this Chapter, page 280. 2 Anoli, native name. 3 Native name. 268 THE LIZAUI) AND ITS ALLIES 269 lives on trees, eats insects, is not timid, can live well in confinement, and, like the chameleon of Europe, has the power of changing its colors from bright green to dirty brown. Besides Anolis we have various other lizards of the family Iguanidse. The horned toad of the Southwest, Avhich has a broad, flattened body and long spines on the head, and lives in dry, sandy places, is a familiar object.1 In the South Central and Southern States lives the elon- gate " swift " of varying color, often with black, irregular FIG. 251. — Phrynosoma, the horned toad. Photo, by E. R. D. cross bands above, with iridescent colors on the throat of the male, and with large, strongly keeled scales and a slender tail. The largest of the Iguanidae is the " leguaii " of the West Indies and South America, which gains a length of 1.75 metres, or over five feet. The family Varanidae,2 or water-lizards, contains the largest known lizards. The Nile varanus attains a length of nearly two metres. It lives on the rivers of Africa, feeds on small Crustacea, birds, birds' eggs, frogs, fish, and occasionally also on young crocodiles and crocodile eggs. 1 Fig. 251. 2 Latinized from the Arabic word waran, lizard. 270 ZOOLOGY The ancient Egyptians regarded these crocodile-like lizards as the greatest enemies of the crocodile. The Lacertidae,1 which are common in middle and south- ern Europe, are agile, harmless creatures, often of bright colors, and are commonly and favorably known. The more FIG. 252. — Lacerta viridis, the green lizard of Europe. After Brehm. abundant are the "green lizard" (Fig. 252), the "sand- lizard," and the " wall-lizard " of the Latin countries. The Helodermidae include the largest lizard of the United States, the so-called " Gila monster," which in- habits New Mexico, Arizona, and the country southward. The lizard is colored brown, with reddish spots and numer- 1 From lacerta, lizard. THE LIZARD AND ITS ALLIES 271 ous yellowish punctations (Fig. 253). It is nocturnal in its habits and its bite is very poisonous, although not often fatal to man. The family Anguidae, or slow-worms, includes the famous glass-snake or joint-snake of the South. * This snake-like lizard has no legs, or only rudiments of the hinder pair. It is noted for the ease with which 'it breaks in two when FIG. 253. — Heloderma, the Gila monster. About two-fifths nat. size. From Brehm. struck or lifted by the tail. This result is due to the fact that, as in certain other lizards, the vertebriB of the tail are unossified along the middle plane, so that they separate at this point upon the slightest blow. The muscles of this species seem also to be arranged so as to facilitate sepa- ration. In Europe there is a lizard of this family, the so-called " blind- worm " (having, however, well-developed 272 ZOOLOGY eyes), which is found in retired localities, from which it comes out, especially in the evening, to capture earth- worms and slugs. . The Chameleon famed in literature comes from Africa. Its change of color depends upon the possession of several layers of different color in the skin, which layers can be separately expanded or contracted as required, as a result of which some one color comes to predominate. It cap- tures insects, a habit which is facilitated by its power of FIG. 254. — Chameleo, the chameleon. From Leunis. protruding the tongue to over half the length of its body and bringing the sticky end in contact with its prey. The protrusions and retractions of the tongue are effected with marvellous rapidity (Fig. 254). While in point of size the lizards of geologically recent times are inconsiderable, those of former epochs were huge. These former or fossil lizards were most charac- teristic of the middle life era or the Mesozoic age. They belong to three main groups; namely, swimming, walking or wading,1 and flying lizards. The swimming lizards were 1 Fig. 254. THE LIZARD AND ITS ALLIES 278 sometimes over 10 metres long, and had feet modified as paddles. The land lizards were elongated, three-toed, carnivorous reptiles, with hollow leg bones like birds. In the flying lizards, a strong compact body was provided with hollow, air-filled bones, and locomotion was effected by a huge membranous expanse stretched between the FIG. 255. — Hadrosaurus. From reconstruction model. Osborn, " Kept. Amer. Mus. Nat. Hist." elongated posterior finger, the trunk, and the hind legs. The spread of the wing was about three feet. The Chelonia,1 or turtles, form an order distinct from the lizards. , They are characterized by a depressed form, a bony case, and toothless jaws. Like other reptiles, they are most abundant in tropical countries, since the high i/r/, turtle. 274 ZOOLOGY external temperature compensates in a way for the insuf- ficiency of the mechanism for maintaining from the inside a high blood temperature. Turtles are abundant in Africa, and are much commoner in North America than in Europe. Three families of Chelonia may be distin- guished. A short account of each follows. The family Chelonidae includes certain marine turtles. Turtles live in all oceans and may acquire a weight of as FIG. 2f)t>. — Hawkbill-turtle. Much reduced. From Brehm. much as one thousand pounds. The green-turtle, used in making soup, occurs on the Atlantic coast as far north as Long Island. From the hawkbill-turtle (Fig. 256) comes the tortoise shell used in certain ornaments. In the leather-back the shields are incompletely ossified. The family Trionychidae 1 includes our soft-shelled tur- tles, which live in rivers or ponds of the Mississippi valley and the Gulf drainage basin (Fig. 257). 1 T/O/J, thrice ; 8vv%, claw. THE LIZARD AND ITS ALLIES 275 The family Testudinidae : includes the hard-shelled, fresh-water and land tortoises. Our snapping-turtle is distributed from Canada to equa- torial South America. It feeds on fish and lays from forty to fifty eggs, which it buries at a depth of about a metre. The alligator snapper of the Gulf States attains the length of a metre, and is re- garded as the " most ferocious and, for its size, the strongest of all reptiles." The box-tortoises oc- cupy the northeastern and central parts of North America. They are well known by the fact that the body is short and high, the plastron is provided with a mov- able hinge, and the carapace is colored black and yellow.2 Other FIG. 257. — Trionyx, three- clawed turtle of the Mis- sissippi valley. Keduced. From Leunis. FIG. 258. — Terrapene Carolina, the box-tortoise. Photo, of living animal by W. H. C. P. 1 From testa, a shell. 2 Fig. 258. 276 ZOOLOGY common tortoises of the eastern United States are the musk- turtle, told by a strong odor of musk ; the painted turtle, of greenish black color and with marginal plates marked with bright red ; the speckled tortoise, black Avith round orange spots ; and the wood tortoise, with keeled shell, and plates marked with concentric striae. The order Ophidia l comprises the snakes, characterized bjr the elongated body without appendages, and by the FIG. 259. — Eutamia, garter-snake, dorsal view. Photo, by E. R. D. absence of eyelids. Like other reptiles, the snakes are chiefly tropical, but inhabit also the temperate zones. They feed on living animals. The family Colubridae 2 includes the great majority of our common non-venomous snakes, such as the garter- snake,3 water-snake, black-snake, milk-snake, and spread- ing adder. Allied are the boas of South America and the pythons of India, which attain the length of six metres or 1 60is, serpent. 2 coluhra, serpent. 8 Fig. 259. THE LIZARD AND ITS ALLIES 277 more. Xot being poisonous their bite is not dangerous, but they attack large birds and even medium-sized mam- mals arid crush them to death in the folds of their body. The family Elapidae l includes the large venomous ser- pents of the East, the cobra of the East Indies, and the asp of the Egyptians. The bite of these serpents is quickly FIG. 2HO. — Elapx corallina, a harlequin snake of South America allied to the bead-snake of the South. From " Standard Natural History," after Brehm. fatal to man. To this family belongs also the bead-snake of our Southern States, which is however harmless (Fig. 260). The Crotalidae 2 include the rattlesnakes, characteristic of America.3 Of this family the most dangerous is the water- 1 €\a\f/. an unknown snake of the ancients. 2 , clapper. 3 Figs. 261, 262. 278 ZOOLOGY FIG. 2(51. — Crotalus, the rattlesnake. Photographed as the snake was about to strike. Taken in Arizona and kindly lent by H. W. Menke, Chicago, 111 FIG. 262. — The rattlesnake. The recoil after striking. Photographed Arizona and kindly lent by H. W. Menke. Note in both figures the elevated rattle, toward the right. THE LIZARD AND ITS ALLIES 279 moccasin or black moccasin, which inhabits the Southern States, and gives no warning noise as does the rattlesnake. The copperhead of the eastern half of the United States is also dangerous, bnt is mostly confined to wooded, moun- tainous regions. The rattlesnake was once common over the whole of the Northern States as far west as the Rocky Mountains, but it is now nearly exterminated in well- settled districts. Related to these are the venomous vipers of Europe. The order Crocodilina contains only some twenty species, distributed in three genera. The gavial is the crocodile FIG. 263. — Head of Alliyaior mississippiensis, the Mississippi alligator. From Leunis. of the Ganges River. It captures even large mammals and man. The crocodile in the strict sense is found in the Nile and other African rivers, in certain countries on the western border of the Pacific, and in northern South America, Central America, and the Antilles. The American alligator, which has a different arrangement of the denti- tion from the crocodiles, occurs in seven slightly differing species, all of' which are South American excepting the alli- gator of our Southern States. It feeds on fish, and attacks horses and even man (Fig. 263). 280 ZOOLOGY APPENDIX TO CHAPTER XVIII KEY TO THE FOUR OKDEKS OF REPTILES Trunk enclosed in a case composed of a dorsal and a ventral shield (carapace and plastron) ; jaws without teeth ."'-.. Chelonia Without encasing shields ; teeth on jaws. ?>i. Teeth in special cups or alveoli ; 4 legs ; cloacal opening a longitudinal slit .. ' . Crocodilina &:>. Teeth not in special alveoli ; cloacal opening a transverse slit. Ci. Shoulder girdle and sternum present ; eyelids usually present . . . Sauna, c-j. Shoulder girdle and sternum absent ; eye- lids absent ; no feet . _. . . Ophidia CHAPTER XIX THE ENGLISH SPARROW AND ITS ALLIES THE term " English " sparrow is somewhat of a mis- nomer, for at the time it was introduced into our country this bird ranged over all Europe, where it is known as the house sparrow. The history of the spread of this bird shows us in a vivid way what are the successful qualities among birds. Originally this sparrow was conhned to middle Europe, and probably made its way into Germany at the time of the Romans. It has since swept all over Europe, including the British Isles, and has penetrated even into Siberia. It has crossed the Mediterranean and is found along the Senegal River, and, probably through human agency, has penetrated to the Cape. It has been transplanted voluntarily by man to North America, Australia, and Java. It seems to occupy among birds the place taken among mammals by the rats. Crafty, pugna- cious, obtrusive, thieving, dirty, it has become a nuisance wherever it has penetrated. But just these pushing quali- ties, combined with small size, great hardiness, a universal diet, and immense fecundity, have enabled it to make its way against^ all competitors. Its introduction into America can only be regarded as a deplorable blunder. Spread of English Sparrow in America. — The first im- portations of the house-sparrow (Passer domesticus) to North America were made at Brooklyn, New York, in 1850 281 282 ZOOLOGY and 1852. The second importation survived and multiplied. Subsequent importations were made to Maine, Rhode Island, and Pennsylvania, so that by 1870 the sparrow was firmly established in the eastern United States. From this time on the sparrow spread at a rate unparalleled by any native bird. By 1886 it had spread as far west as Kansas, and had established colonies at Salt Lake City, San Francisco, and other outlying regions ; and through- out this territory it occurred in great abundance. Since then it has penetrated west to the Rocky Mountains, and south to Texas. This extraordinary spread has been due to several causes. As already suggested, the bird can adapt itself to various climatic conditions, and its fecundity is very great. Thus in our Southern cities there are from five to six broods a year, and from four to six young in each brood. Assuming that twenty-four young, half of them females, are produced by a pair each year, and that all the females breed when one year old, and successively for ten years, and that there are no deaths, then in the tenth year 138,000,000,000 individuals will have been pro- duced from the original pair. To the realization of the possible maximum of reproduction there are, however, many checks, especially the destruction of birds by ac- cidents, disease, and beasts arid birds of prey. Food of English Sparrow. — The house-sparrow was in- troduced for the purpose of destroying or holding in check the "canker-worm" and the various other caterpillars which destroy our fruit, forest, and shade trees. There is much doubt, however, whether the house-sparrow is at all effi- cient in the way of destroying insect pests, while it is quite certain that it fights with and drives away our native insect-eating birds. More important still, it de- THE ENGLISH SPARROW AND ITS ALLIES 283 stroys large quantities of grain in the field, as well as many kinds of garden produce, so that, on the whole, the English sparrow must be reckoned destructive to agri- culture. Of late years it has come into our Southern markets as a substitute for the rice-bird. Increase of Exotic Species. — The extraordinary spread of the English sparrow after importation to this country is not wholly explained by its large fecundit}^; for although equally reproductive in Europe, it increases less rapidly there than here. Also it is not due to any peculiarity of our country, for the bird is a similar pest in Australia. Similar facts concerning the spread of other animals lead us to conclude that it is the new country which permits the rapid spread and consequent destructiveness. Thus when the cabbage-butterfly (^Pieris rapce) was brought to this country it spread with such rapidity that, starting in 1860 at Quebec, it has now spread all over the United States as far as the Rocky Mountains. Again, the grape- vine insect pest, Phylloxera, a native of this country, but not particularly destructive here, has been accidentally transported to France, and there it has wrought great havoc in the vineyards. Another instance, this time of an aquatic animal, shows the same result : the periwinkle, Littorina littoria, now the commonest snail on the seashore north of New York, has migrated down the shore from Halifax since 1868. This old species in the new country has almost driven out the other shore mollusks, to such an extraordinary degree has it multiplied. Now why should animals in a' new country develop with such unusual rapid- ity ? It is because coming into a new country they have left behind them their natural enemies, and there has not yet been time for them to acquire new ones. Eventually 284 ZOOLOGY the new enemies are gained or their bid ones overtake them, and then the numbers of the exotic form become reduced ; a new equilibrium becomes established. The English sparrow belongs to the family Fringillidae, which includes sparrows and finches. This is a large FIG. 1?(J4. — The American crossbill (Loxia curvirostra) . family, comprising over live hundred species, found in all parts of the world, excepting, originally, Australia. In the United States this is the largest family of birds, com- prising in most places about one-seventh of the species. Among common or striking native Fringillidse may be THE ENGLISH SPAKTIOW AND TTS ALLIES 285 mentioned the crossbills,1 yellow-bird, vesper-sparrow, white-throated sparrow, tree -sparrow, dripping-sparrow,2 snow-bird, song-sparrow, fox-sparrow, chewink, cardinal grosbeak, rose-breasted grosbeak, and indigo-bird. Most of these birds are known to every country boy. The family of Turdidae, or thrushes, includes several common American birds, — the robin, abundant about FIG. 2fi5. — Chipping-sparrow (Sp/.zella socialis). houses during the summer but for the most part migrat- ing south from New England during the winter ; the wood or song thrush,3 one of our finest songsters ; the bluebird, one of the earliest of our migrants, with " the sky on its back and the earth on its breast." The family of Sylviidae comprises the " warblers " of the Old World'. Here belongs the European nightingale. Its common representative in this country is the ruby-crowned kinglet (Fig. 267). 1 Fig. 264. 2 pig< 265. 3 Fig. 266. 286 ZOOLOGY The family of Paridae includes the titmice, or tits and nuthatches. The tits are chiefly Old World birds, but we have a common representative in the black-capped chicka- dee, well known from its cheerful whistle. In this family FIG. 26(5. —Wood-thrash (Turdus mustelinus). belong the nuthatches which run over tree-trunks, head up or down, indiscriminately (Fig. 268). The family of Certhiidae includes the little brown creeper which runs over tree-trunks much as the nuthatches do and uses its tail-feathers as props against the tree-trunk (Fig. 269). THE ENGLISH SPARROW AND ITS ALLIES 287 The Troglodytidae, or wrens, are characteristic of South America, but some have spread into North America and north- ern Europe. Our house-wren, which is a near relative of the European house-wren, is an ac- tive little brown bird, with a sharply bent-up tail.1 In this same family belong the mock- ing-birds, the centre of whose distribution is Central America, the West Indies, and the south- FIG. 268. — White-breasted nuthatch (Slthi carolinensis) . FIG. 42(>7. — Golden-crowned king- let (Reyulus satrapa). ern United States. The large brown thrasher and the cat-bird are familiar over the country. The mocking-bird does not get far north into New- England. It is regarded by many as superior to the nightingale as a singer. The family of Mnioti- lidae, or " wood - war- blers," is the peculiar glory of America. It i Fte. 270. 288 ZOOLOGY contains numerous small, mostly brilliantly colored birds, which migrate. Although a few of them — like the red- start, the Maryland yellow-throat (Fig. 271), the redpoll warbler, the chestnut-sided warbler, and the yellow war- bler— are abundant, few of the thirty -five or forty Eastern FIG. 2(59. — Brown creeper ( Cerithia familiari*) . FIG. 270. — House-wren (Troglodytes ai'don). species can be said to be commonly known except to careful observers of birds ; for during the migrations they hide in thickets, and are extremely shy. The Vireonidae include the vireos, or greenlets, bright, handsome, and exclusively American birds. The com- THE ENGLISH SPARROW AND ITS ALLIES 289 monest species are the red-eyed vireo (Fig. 272) and the yellow-throated vireo. The Laniidae, or shrikes, are of world- wide distribution. They are vigorous, pugnacious birds, which have the habit FIG. 271. — Maryland yellow-throat (Geothlypis trichas). of impaling grasshoppers and other small animals upon thorns, and leaving them there. In Germany there is a tradition that the shrike daily impales nine victims, and it is hence commonly called Neuntodter, or " ninekiller." The 290 ZOOLOGY FIG. 272. — Red-eyed vireo (Vireo olivaceus). FIG. 273. — Great northern shrike (Lanius boreal i THE ENGLISH SPARROW AND ITS ALLIES 291 impaling seems to be done chiefly in the winter time, and apparently has for its purpose the storing of food against possible famine. Among birds frequently destroyed by them is the English sparrow, and it has been suggested that the shrikes should be encouraged to live in parks of cities FIG. 274. — Cedar waxwing (Ampelis cedrontm). infested by sparrow pests ; but unfortunately the shrikes do not confine themselves to this intruder. We have two species of shrikes, a northern (Fig. 273) and a southern. The Ampelidae, or waxwings, are found over the Northern Hemisphere. They are migratory, go in flocks, feed on 292 ZOOLOGY insects and fruits, and chatter rather than sing. Our commonest species is called " cedar-bird" (Fig. 274). FIG. 275. — Barn-swallow (Chplidon ery thro ff after) . The Hirudinidae, or swallows, are found over the world. They are powerful fliers, and are insectivorous. Formerly all of them bred in boughs, cliffs, and hollow trees, and some species still retain these habits. The best-known species are the bank-swallows, which, living in colonies, form numer- ous holes in railroad cuts and sandbanks in general ; the white-bellied swallow, abundant about water ; and the barn-swal- low (Fig. 275), with a chestnut belly, which builds its nest in the rafters of our barns (Fig. 276). The Tanagridae, or tanagers, are exclusively American, and belong especially to the tropics. They live in the FIG. 276. — Nests of barn-swal- low. Photo, by D. and S. THE ENGLISH SPARROW AND ITS ALLIES 293 woods, and feed on berries and fruits. The northernmost member of the family is the scarlet tanager of the eastern United States (Fig. 277). The Icteridae include numerous species with different habits. These are also confined to America, and are especially abundant in the tropics. They feed, for the FIG. 277. — Scarlet tanager (Pimnya erythomelas}. most part, on seeds. The commonest representatives are the crow blackbird,1 of large size and iridescent plumage ; the Baltimore oriole, which weaves a hanging nest ; the orchard oriole, with less orange than the preceding ; the large meadow-lark, brownish above and yellow below ; the red- winged blackbird ; the cow-bird, which builds no nest but lays its eggs in the nests of various small birds ; 294 ZOOLOGY and the "bobolink," as it is called in the North, whose song is the merriest of all birds. In the South, whither the bobolink migrates in the winter, it is a great pest in FIG. 278. —Purple grackle (Quiscalus quiscula). the rice-fields, and is known as the "rice-bird." It is slaughtered there as a game-bird. The Corvidae include the crows and their allies, all of them birds of large size. The crow, the raven of the West and of Europe, and the blue jay (Fig. 279) are the com- monest North American species of this family. THE ENGLISH SPAEEOW AND ITS ALLIES 295 The Alaudidae, or larks, are a family chiefly of Old World birds of dull color, building a rough nest on the ground, and feeding on seeds and insects. The skylark of Europe is renowned as a songster. In this country we have one . FIG. 279. — Blue jay (Cyanocitta cristata). representative of the family, the horned lark, found also in Europe. The Tyrannidae, or flycatchers, are an exclusively Ameri- can family, feeding on insects. The best-known represen- 296 ZOOLOGY tatives are the courageous king-bird (Fig. 280), the wood pewee (Fig. 281), and the water-loving phoebe. FKJ. 280. — Kingbird (Tyranmis tyrannus). FIG. 281. — Nest of pewee. Photo, by D. and S. THE ENGLISH SP Alt ROW AND ITS ALLIES 297 We will now pass in brief review the principal Orders of Birds other than Passeres. The Psittaci include the parrots and cockatoos. In the cockatoos the feathers of the head are elevated to form a crest. In the parrots there is no such crest ; in one subdivision the tail is long ; in a second, very short. The representatives of this FIG. 282. — Conunts carolinensis, the Carolina paroquet. One-fifth nat. size. After Wilson. family are found almost exclusively in the tropics, in Brazil, the Moluccas, and in Australia. In general, these" birds have a loud voice, and certain species may be trained to articulate words and combine them into sentences. There is only one parrot native to the United States — the Carolina paroquet (Fig. 282). This formerly occurred 298 ZOOLOGY north to the Ohio River, but it has been within recent years practically exterminated by plumage hunters. The Raptores include eagles, hawks, and falcons ; the vultures; condors; and owls. These birds feed chiefly on FIG. 283. — Sharp-shinned hawk (Ac- FIG. 281. — Screech owl (Meyascops cipiter velox) . asio) . birds and mammals, which they capture alive in their claws or beaks ; a few live on carrion. They occur in all parts of the globe. The bald eagle, used as a symbol of the Republic, is the commonest of our eagles. Among THE ENGLISH SPARROW AND ITS ALLIES 299 our hawks, the sparrow-hawk, which is only about the size of the robin, is one of our commonest ; others are the sharp-shinned hawk, which kills birds almost ex- clusively, and is especially destructive to poultry,1 and Cooper's hawk, which is also destructive to birds. These two hawks have practically no redeeming qualities, ex- cept the fact that they prey upon the English sparrow. The vultures are represented in our fauna by the turkey-buzzard, Avhicli, like other members of the family, feeds on carrion. The European and African vultures even exceed the turkey-buzzard in size. The condor is the largest of the American Raptor es. It preys even upon live sheep and calves. The owls, which live in dark holes and feed upon small mammals at night, are found over the globe. Our commonest species is the reddish gray screech-owl.2 The great horned owl is an inhabitant of wooded tracts, and is destructive to poultry and small mammals. The snowy owl is one of the handsomest of all owls, and is frequently seen stuffed in houses in Europe as well as in North America. The Scansores include the toucans and cuckoos on the one hand and the woodpeckers on the other. The toucans are characterize^! by an enormous bill, which in extreme cases is as long as the rest of the bird. It would be ex- tremely heavy were it not filled with air spaces of great extent. These birds inhabit Brazil. The great bills are of use in feeding on fruits. Filling the place in the Old World of the toucans of the New are the hornbills of Africa and Asia, which are likewise frugivorous. The cuckoos are typically represented by the Old World cuckoos. Like our own cow-bird, they have the peculiar ig. 283, 2 j^. 284. 300 ZOOLOGY habit of laying their eggs in the nests of other birds, espe- cially insectivorous birds, where they are brooded and the young are fed by the foster-mother. Our native cuckoo, however, broods its own eggs, and is a useful insectivo- rous bird. The kingfishers are also placed in this group. •. •• ' '' '"-'•C:;/3^'-- Fio. 285. — Belted kingfisher ((Jenjle alcyon}. They are especially an Old World family, but one genus, Ceryle, has found its way into North America and even into South America. These birds feed chiefly on fish, and they have gained a compact oily plumage to prevent them from getting wet when they plunge for their prey. Our species is known as the belted kingfisher (Fig. 285^). THE ENGLISH SPAEEOW AND ITS ALLIES 301 The woodpeckers include for the most part arboreal birds which feed chiefly on insects and have loud, harsh cries. The common idea that they are sap-suckers and destructive to trees seems to be true only of one of our species — the yellow- bellied woodpecker. The heavy, long bill enables woodpeckers to peck holes in trees for wood-eating in- sects, and the long, barbed, protrusible tongue aids in remov- ing the prey. Our commonest woodpeck- ers are the golden- winged woodpecker, or flicker,1 the red-headed woodpecker, the hairy woodpecker, and the d o w 11 y woodpecker. An interesting ques- tion concerning the golden -winged wood- peckers of the East and Southwest is whether . , i -I • T i FIG. 28(5. — Flicker (Cotaptes auratus) . they hybridize where their areas of distribution overlap. The Cypselomorphae include fhe humming-birds, swifts, and goat-suckers. The humming-birds are mostly small species, limited to our hemisphere, and characteristic of i Fig. 286. 302 ZOOLOGY the tropics. One species, the ruby-throated humming- bird, reaches New England and Canada. These usually brilliantly colored birds feed on insects and nectar, which they gather from floAvers. They fly with great swiftness, nest in trees, and lay only two white eggs (Fig. 287). The Swifts have a broad gape, and no bristles at the base of the bill. They have habits much like swal- lows, and are found especially in the warm parts of the world. FIG- 287. — Ruby-throated humming-bird \ . (Trochilux colubns). Most Species OI this family have salivary FIG. 288. — Nest of chimney-swift. Photo, looking down chimney, hy D. and S. THE ENGLISH SPAEROW AND ITS ALLIES 303 glands, whose secretions aid in cementing the nest. Our common representative of this group is the chimney-swift, or chimney-swallow.1 Certain Chinese species make nests entirely of the mucilaginous secretion of the salivary glands ; these constitute the edible birds'-nests of the Chinese. The goat - suckers include night-flying birds, with exceedingly broad gape and insectivorous habits. The night - ha\vk of North America, and the whippoorwill, noted for its characteristic night cry, are familiar ex- amples. The order Columbinse includes the pigeons and allies, characteristic of the Eastern Hemisphere. The most interesting species of the group — the dodo and the soli- taire, formerly inhabit- ants of the islands of Mauritius and Rodri- guez, respectively — have become extinct within historic times through the settlement of these islands by white men. These birds had rudimentary wings and tail. Their nearest living i Fig. 288. FIG. 289. — Passenger pigeon (Ectoplstes miyratorlus) . 304 ZOOLOGY ally seems to be the "manu-mea1 " of 'the Samoan Islands. The pigeons proper are represented in North America by three wild species (Fig. 289). The domesticated pigeon, Ootumba livid, is a native of southern Europe or western Asia. The order Gallinacei includes a number of terrestrial birds of large size, especially the grouse or partridges, the pheasants and common fowl, the guinea fowl, and the tur- FIG. 290. — Ruffed grouse (Bonasa umbellus). keys. On account of their large size and well-flavored flesh, they are much used as human food. The grouse of America include the familiar " bob-white " or quail, which is undergoing a rapid extermination in populous regions ; the Canada grouse, which does not occur south of New York; the ruffed grouse of the Eastern States;2 and the prairie chicken of the Great Plains, which has also become almost exterminated. In Europe the large 1 Red-bird. 2 Fig. 290. TIIK ENdLfSII SPARROW AND ITS ALLIES 305 " capercallie " and the blackcock are favorite game-birds. The pheasants are characteristic of southern Asia and China; they comprise some of the most brilliantly colored and greatly ornamented of birds, such as the peacock and the golden pheasant. Here also belong our barnyard fowl, derived from a wild species, Grallus bankiva, inhabit- ing northern India, the Kast Indies, and the Philippines. The guinea-fowl is a native of Africa, where it goes in large flocks and is difficult of approach. The turkeys are North American birds. The wild turkey formerly occurred over all the United States and Mexico. It was first taken to Europe in 1524, was domesticated there, and now occupies much of its former habitat as a domesticated fowl. From this brief view we see that the family of (lal- linacei is, for man at least, one of the most important families of birds. The Grallatores, or waders, include a great number of shore birds known as plovers, sandpipers, snipes, rails, cranes, herons, and storks. The plovers walk and fly along shore, picking up worms, mollusks, and amphibians; the golden plover and the killdeer are well-known game- birds. The snipes are found in meadows or, less com- monly, in woods. One of the most common is the spotted sandpiper, also called u tip-up " from its rocking move- ments (Fig. 291). It is seen walking around small pools of water by the roadside or in fields. Along the coast are found woodcock and large snipes. Among the herons, our great blue heron attains a length of four feet and is a notable resident of swampy regions; the egrets have been practically exterminated to meet the demands of milliners ; the bittern is still common on tide-flats. The Natatores, or swimmers, comprise the ducks and 306 ZOOLOd Y geese, the pelicans, the petrels, the gulls and terns, and the divers. Of the geese, the wild goose, or Canada goose, is most commonly seen in. its migrations. Of the native ducks we have many kinds, almost all rapidly disappear- ing before the u sportsman." The pelicans are large fisli- eating birds, with a huge bag-like lower bill. In this country the white pelican is not uncommon. The large- FIG. 291. — Spotted sandpiper (Actitis macularia). winged petrels follow in the wake of coastal vessels. The terns, which are slender birds with a straight bill,1 Avere once abundant along our coast, but have been decimated to " ornament " bonnets. The gulls, which are heavier than the terns and have hooked bills, are still abundant over all bodies of water. Finally, the loons are large birds, i Fig. 292. THE ENGLISH SPARROW AND ITS ALLIES 807 powerful fliers and swimmers, which are found in the lakes of the Northern Hemisphere. They are quick divers, and can swim under water for a considerable distance. The order of Cursores includes the African ostrich, the American ostriches or rheas, the cassowaries of the East Indies, and certain wingless birds of New Zealand (Ap- FKJ. 292. — Common tern (Sterna hirundo}. teryx *) . These are regarded as the most lowly developed of the birds ; the vanes of their feathers are not united, but separate to form a sort of hair-like covering to the body. The African ostrich is the largest living bird. It wanders in families or flocks in the deserts of Africa, and feeds on grass, grain, and small animals. It also swallows undigestible matters, such as stones, which probably aid i Fig. 293. 308 ZOOLOGY it in triturating its food. The nest consists of a hollow scooped out of the earth, into which about thirty eggs are laid. Ostrich feathers are used for ornament, and so important is the commerce in these articles that ostriches FIG. 293. — Apteryx australis with egg. From a specimen in the Royal College of Surgeons, London. From Parker and Haswell, " Text-book of Zoology." are extensively farmed in South Africa. When reared in. captivity the eggs are hatched in an incubator, and the young carefully fed. The feathers are cut off and not pulled out, so that the operation of gathering the feathers is a painless one. THE ENGLISH SPARROW AND ITS ALLIES 309 Bird Migration. — The birds of any territory may be classified on the basis of their residence into four groups : permanent residents, winter residents, summer residents, and transient visitants. In NCAV York the permanent residents are represented by the screech-owl, the crow, and the gold-finch. Winter visitants are represented by the snow-bird and white-throated sparrow ; summer resi- dents by the wood-thrush, cat-bird, yellow warbler, bobo- link, and barn-swallow ; transient visitants by most of the warblers, the fox-sparrow, and white-bellied swallow. As this classification indicates, the bird fauna of any place is, to a great extent, shifting from season to season. In the spring at any latitude many species are seen passing far north, and in the autumn passing south again. Tem- perate as well as southern latitudes receive in the winter time the southern edge of a more northern fauna. Thus geese and ducks are forced by the universal ice of the Arctic winter to go to regions of open water, at least. Many kinds of birds which spend the winter in the South come North to breed. For example, the bobolink is found nesting in the New England fields in summer, and is then altogether absent in the South. In the fall this bird is not found in New England, but occurs in the Gulf States as the rice-bird. The cause of this migration on the part of birds breeding in the North is the need of food. Insectiv- orous birds, especially, could not obtain food enough in the North in winter. Migration Routes. — It is known that many species which migrate even great distances travel along well- defined paths. In Europe the paths of the shore migrants have been carefully mapped out. It appears that these birds follow the shore line very exactly, except in some 310 ZOOLOGY cases in which it can be demonstrated that their paths are along ancient shore lines. As Wallace says : " It is easy to see how the migrations that had once taken place over continuous land would be kept up first over lagoons and marshes, then over a narrow channel, and subsequently over a considerable sea, no one generation of birds ever perceiving any difference in the route." The migration routes of North America have not been well studied. The Atlantic coast is one line ; the Mississippi valley, for- merly, no doubt, an arm of the sea, is another route along which even sea-birds now migrate. The question how birds recognize and are able to follow their migration routes, is a difficult one ; they seem to have a marvellous sense of direction. There is great need of a more perfect knowledge of migration phenomena in North America. Every one who has learned to distinguish accurately the species of birds can contribute to this knowledge by keep- ing records of the time of appearance of migrants in the spring and the fall. The American Ornithologists' Union has for many years solicited observations on this subject from voluntary collaborators. Bird Flight. — The difficulties which must be overcome in order to fit birds for flight are, first, that of sustaining the heavy body in a medium of such low specific gravity as the air and, secondly, that of progression in this medium. To diminish the difficulty of sustaining the body, the specific .gravity is reduced to a minimum by great air- spaces in the body, which exist even in the hollow bones.' The body is kept from being overturned in the air by the position of the wings, which are placed high up on the trunk while the digestive organs, breastbone, and breast muscles are placed low. To aid locomotion, the general THE ENGLISH SPARROW AND ITS ALLIES 311 form of the body is made conical, so as to offer little re- sistance to the air, while, by varying the position of the head, wings, and tail, the centre of gravity is quickly shifted. In starting to fly, the bird gains an initial veloc- ity, if on the ground, by springing into the air, or if on a tree, by combining the velocity due to gravity with a push- ing from the limb ; but aquatic birds strike the surface of the water with their wings. The best fliers have relatively large, pointed wings. Three methods of flight are em- ployed by birds when once in the air : (a) stroking the air with the wing; (£>) gliding or skimming ; and (c) sailing or soaring. Some birds can use all three methods, and all good fliers use the first two. In the stroke the wing moves downward and forward, backward and upward, so that the tip of the wing describes a OO ; and the plane of the wing constantly changes so as to push downward against the air, and thus keep the bird up, and to push backward against the air, and thus drive the bird forward. At the same time, the wing must be brought back to its upper and anterior position without offering great resistance to the air. In gliding, the wings are spread, but are not flapped, — progression depends upon an acquired velocity or upon the wind. In soaring, the wings remain motionless, and the bird does not lose its velocity nor tend to fall. The way in which the bird is supported and carried along is uncertain. It seems to depend upon certain favorable currents in the air. Birds, like insects, have the closest economic relations with man. A few of them, chiefly belonging to the orders of Natatores and Gallinacei, are very important as human food; but most of them concern man on account of their feeding habits, which are either favorable to man, as when 312 ZOOLOGY noxious insects are destroyed ; or injurious, as when grain- fields are ravaged or other birds are destroyed. Un- questionably the vast majority of birds are commercially advantageous to man. The Rapt ores are only partially so, for they feed entirely upon animal food, chiefly birds and small (usually destructive) mammals. The bobolink and the American crow, to be sure, together annually destroy millions of dollars' worth of grain, yet during the breeding season they both feed much upon insects. Outside of the group llaptores, there are few, if any, completely noxious birds, and even many of the hawks are efficient destroyers of insects. Legislation directed toward the destruction of any kind of birds, excepting the English sparrow and the Cooper's and sharp-shinned hawk, is quite as apt to do harm as good. Bird Protection. — Travellers in certain parts of Europe, where the poverty and ignorance of the people have led them to prey upon birds, have remarked on the desolation of a birdless country. The natural enemies of insects being destroyed, there is no adequate check to the destruc- tion of vegetation by them and the beauty of a forest landscape is missing. North America has been richly provided witli a native bird fauna ; but within the last few years it has become plain that most of our species are undergoing reduction, and many are near extermination. Careful inquiries recently made indicate that during the past fifteen years the number of our common song-birds has been reduced one-half, and the number of certain birds prized as food or ornament has been reduced to one-fourth. At the present rate, extermination of many species will occur during the lives of most of us. The causes of this destruction of birds are numerous. The most efficient THE ENGLISH SPARROW AND ITS ALLIES 313 cause is the shotgun in the hands of boys and thoughtless men, and of those who gather birdskins to meet the demand for bonnet u ornaments." Very great destruction is also caused by egg-collectors, who annually gather scores of FIG. 294. — Hesperornis regalis. The restored skeleton. After Marsh. thousands of eggs, often of rare birds. The disastrous results of killing birds need only to be appreciated in order to put a stop to this destructiveness. Extinct Birds. — The destruction of species of birds goes on fast enough without the more efficient aid of man. 314 ZOOLOGY We know of species which have become extinct within recent times through the introduction of new enemies among them. Such was the fate of the dodo. Then remains have been preserved to us in the rocks of species which lived in very remote periods. The oldest known fossil bird, ArchaDopteryx, of the Jurassic age, had a long tail like a lizard ; but feathers, which are only modified scales, were present even in this oldest known bird. In the Cretaceous rock deposits of the Great Plains there have been found fossil birds with teeth set in sockets or grooves, precisely as they are to-day in reptiles (Fig. 294). These remains show us in the clearest manner that birds have been derived from reptiles. Indeed, the two groups are closely related anatomically, and are often united under the name Sauropsida or lizard-like animals. APPENDIX TO CHAPTER XIX KEY TO THE ORDERS OF BIRDS a\. Sternum with keel for insertion of flying muscles [Carinatse]. bi. Toes more or less webbed or fringed, legs used for swimming or wading. c\. Short legs, broadly webbed [Swimmers] Natatores Ct. Long legs, long, thin neck, and long beak [Waders] . ' . .... . . ' .. , Grallatores b%- Feet not webbed, fitted for walking, d- With cere. c?i. Beak strong, and bent downward at point ; perching feet ; flat nail . G-allinacei dz. Beak not bent downward at point-; short, cloven feet; nail com- pressed ..... Columbinw APPENDIX TO CHAPTER XIX 315 d$. Beak hooked ; strong, sharp, hooked claws ...... Eaptores d±. Beak shorter than high ; thick, fleshy tongue . . . -...'. Psittaci C2. Without cere. d±. Beak long, often heavy ; tongue thin ; stiff plumage with little down ; metatarsus with half rings on scutes; feet scansorial . . . Scansores d%. Metatarsus with no scales or rudi- mentary ones ; feathered in upper part . . . . . Cypselomorphce t?3. Metatarsus covered with laminae or scales, rarely feathered, usually with singing apparatus ; feet not scansorial, mostly migratory .;. Passeres Sternum without keel [Ratitse] . . .. ...* . Cursores KEY TO THE FAMILIES OF PASSERES OF NORTHERN UNITED STATES, BASED ON D. S. JORDAN «i. First of the 10 primaries more than f length of longest of the others [Clamatores] . . . Tyraimidce «2- First of 10 primaries short, rudimentary or ab- sent ; musical apparatus highly developed [Oscines]. 61. First primary short or spurious [primaries 10]. Ci. Tarsus booted ; rictus with bristles. d\. Middle toe quite free from inner ; birds of moderate size ; length more than 15 centimetres. e\. Wings when folded not reaching beyond middle of tail ; no blue Turdidce • e%. Wings reaching beyond middle of tail ; ours chiefly blue . Saxicolidce c?2- Middle and inner toe connected at base ; length less than 13 cen- timetres . •„ , . Sy1viid.ce c2. Tarsus scutellate in front. d\. Nostrils concealed by bristly feathers. 316 ZOOLOGY ci. First primary not more than £ length of second ; length less than 20 centimetres. /i. Bill as long as head ; wings longer than tail . . tiittidte /2. Bill much shorter than head ; wings about as long as tail Paridas e%. First primary more than \ lengtli of second j length more than 20 centimetres . . , : Corvtdce d2- Nostrils exposed or merely overhung by feathers, ci. Bill notched near tip. /i. Tail longer than wings ; gen- eral color gray or ashy brown. g\. Bill very stout and deeply notched and hooked ; bird over 17 centi- metres . ';'„. . Laniidce f/o. Bill neither stout, notched, nor hooked ; bird over 17 centimetres Turdidce 2. Hind claw not twice as long as middle claw. /i. Bill stout, compressed, hooked at tip ; tail not blotch* d with red or yellowr . • . •- Vireonnlie /2. Bill various ; little, if at all, hooked ; colors often brill- iant . .... . Sylvicolidct CHAPTER XX THE MOUSE AND ITS ALLIES THE mouse belongs to the class Mammalia,1 character- ized by having milk glands whose secretion is used to nourish the young, and hair, which may be nearly or quite absent as in the case of porpoises or whales.2 The distribution of the house mouse, from which the different kinds of fancy mice have been derived, is now co- incident with that of civilized man ; but in early times it was limited to Asia. From Asia it made its way to Europe, and thence by vessels to other continents. It was imported to America (which has no indigenous members of the genus Mus) by the early explorers. There have also been im- ported to this country three other species of this genus, of such size that they are commonly called rats. Of these, the roof rat seems to have been imported by the early Spanish discoverers to the Southern States, where it still persists. It originated in Egypt. The second was the black rat, believed to have been imported to America about 1544. It has existed from time immemorial in Europe ; it has a mild disposition, and from it the white rats we keep as pets have been derived. The brown, or Norway rat, has been the latest importation. The history of its migra- tions has been written. Probably originating in central 1 mammalis, belonging to the breast. 2 A key to the orders of Mammalia will be found in the Appendix to this Chapter, page 331. 318 THE MOUSE AND ITS ALLIES 319 Asia, it crossed the Volga hi great troops in 1727, occupied Russia in 173Q, France in 1750, and Denmark about 1810. Before the advance of this powerful and aggressive foe, the black rat of Europe gave way, and became Avell-nigh exterminated, although of late it is said to be reasserting itself in Germany. The brown rat was introduced into America in 1775, has spread over the whole country, reaching the Pacific coast about 1855, and, as in Europe, has nearly exterminated the black rat. The habits of rats and mice are well known. They inhabit our buildings, gnaw our doors and furniture, de- stroy our provisions, kill poultry, and aid in spreading disease. They shun the light, living in holes during the day, run with great agilit}^ and are capable of making long leaps. Owing to their instinct to go into holes, they are easily trapped by a funnel-shaped opening leading into a closed box. Despite the ease of trapping and their destruction by cats, they maintain themselves by virtue of a great fecundity, for, if no deaths occur, several hundred young may, in one year, descend from a single pair. The food of mice is very varied. They naturally thrive best on a vegetable diet; oats especially are recommended for tame mice, and hard-shelled nuts are useful because the mice keep their teeth sharp by gnawing the shells. If the teeth are not kept worn off they soon become incon- veniently long owing to the fact that they grow continu- ously throughout life, and are not formed, once for all, like our teeth. In addition to plant materials, rats and mice eat a certain amount of animal food. The different races of tame mice illustrate the results obtained by preserving sports and selecting the best for breeding purposes. The white mouse, for instance, is an 320 ZOOLO<; r albino ; that is, an animal without pigment. Albinos oc- cur among almost all kinds of mammals, but the cause of them is unknown. So, likewise, the black race of tame mice is due to an excess of pigment, a sport found now and then among other mammals. The pure reddish brown races have probably been produced by selecting the house mice with little black in the fur. By preserving occasional sports and by selecting for breeding the purest-colored individuals, all the different races of our domestic animals and plants have been established and improved. . Other Rodents. — The mouse belongs to the group Ro- dentia,1 distinguished from other mammals by the fact that FIG. 295. — Geomys tuza, the Georgia gopher. One-half nat. size. After V. Bailey. the cutting teeth grow continuously throughout life, a con- dition associated with the habit of gnawing. This group is very abundantly represented in North America, more so, indeed, than in other continents. All our rodents fall into seven families: (1) the squirrels, gophers (Fig. 295), prairie dogs, and woodchuck, with long and hairy tail; (2) the beaver, with broad and scaly tail ; (3) the pouched gophers, with peculiar cheek pouches opening outside the 1 From rodere, to gnaw. THE MOUSE AND ITS ALLIES 321 mouth; (4) the jumping mice, with greatly elongated hind legs; (5) the muskrat and the various wood and field mice, closely related to the genus Mus ; (6) the por- cupines, with bristles replacing hairs ; (7) the hares, with long ears and short tails. All of these familiar rodents are, on the whole, destructive to agriculture. As there are, however, other interests in life than agriculture, it is to be hoped that the warfare against our native rodents will not be too relentlessly pursued. At least one interest- ing species has been rendered well-nigh extinct by the FIG. 296. — Ornithorkyncnus anatmus, the duckbill. After Vogt and Specht. avarice of fur hunters — this is the American beaver, an animal which has developed extraordinary instincts for the construction of dams and subaquatic passages. Other Mammals. — The Monotremata1 are the lowest mammals, and in many ways seem to connect the class with reptiles or amphibians. The milk glands are in a s, single, r/o^a, hole or opening ; so called because urinary, geni- tal, and alimentary canals have a common external opening. Y 822 ZOOLOGY low state of development and eggs are laid, as in reptiles and birds. There are two principal types, — the "Duck- bill " (Fig. 296), with aquatic habits, and the " Spiny Ant-eaters " (Echidna, Fig. 297), inhabiting rocky places. Both types are confined to Australia and neighboring islands. The Marsupialia l have a remarkable distribution over the earth to-day. All are confined to Australia and adja- FIG. 297. — Echidna aculeata, the spiny ant-eater. After Vogt and Specht. cent islands, excepting the family of opossums (Fig. 298), found only in the Americas. There is thus a great dis- continuity in the distribution of marsupials. This is accounted for by the evidence that formerly the whole world contained marsupials, so that those living to-day are the separated remnants of that once universal race. The opossums are most numerous in the tropics, but the Vir- ginian opossum ranges north to New York. 1 marsiiphim, a pouch. THE MOUSE AND ITS ALLIES 323 The Edentata,1 few of which are entirely without teeth, include the sloths, hairy ant-eaters, armadillos, scaly ant- eaters, and aardvarks, or African ant-eaters. The three first-named families inhabit South America ; the two latter, Asia and Africa. Here, again, the discontinuity of the group indicates what fossils prove, that the Edentates FIG. 298. — Didelphys virginiana, the North American opossum. After Vogt anrd Specht. have been killed off from the connecting continents. The sloths have incisor teeth, live in trees, and eat leaves (Fig. 299). The armadillos are protected by strong plates de- veloped in the skin ; they are chiefly nocturnal and om- nivorous animals, and burrow rapidly. The other three families feed on ants and termites, lack complete teeth (ex- cepting the aardvarks), and are either arboreal or burrowing. 1 e, out ; dens, dentis, tooth. 324 ZOOLOGY The Cetacea1 have taken to an aquatic life, for it is certain that their ancestors were land animals. The sea- cows (manatees2), found in rivers in various parts of the world, seem3 to show a transition to the marine forms, FIG. 299. — Choloepus, the unau or two-toed sloth. After Vogt and Specht. such as the dolphins, the toothed whales (Fig. 300), and the toothless or whalebone whales. The largest of these whales — the Greenland whale — reaches an ex- treme length of twenty-two to twenty-four metres, and a 1 cetus, whale. 2 From a native name. 3 The relation to Cetacea is not close. THE MOUSE AND ITS ALLIES 325 weight of over 100,000 kilogrammes. It is, indeed, the largest living animal. Although whales in general are partly adapted to an aquatic life, they still retain the essential mammalian qualities. They breathe air which passes to the lungs and is expelled again through the nostrils, which are placed high up on the head. The " blowing " of the whale is the forcible expiration of moisture-laden air, which becomes visible by condensation, . ttb. " ~ _ _ FIG. 300. — Orca, the killer whale. After True. just as our own breath does on a cold day. The young are doubtless born in the water, but the breeding habits are poorly known. The various Cetacea have diverse feeding habits. All are predaceous. The toothed whales feed on larger animals, the whalebone whales on floating fish, Crustacea, medusae, and squids ; their whalebone is, indeed, merely a strainer to let the water pass out of the mouth while the solid masses are retained. The order Ungulata1 includes a large number of animals, 1 unyula, hoof. 326 ZOOLOGY almost all of which are closely related. In the true ungu- lates there are never more than four functional toes ; but in the subgroup of Subungulata, containing the elephants and certain small animals allied to the "coney" of Scripture, there are typically five. Of the true ungulates, we distinguish the even-toed and the odd-toed, which we may consider further. m FIG. 301. — Stone's Alaskan black sheep. Photo, of a group m the Field Columbian Museum. The Even-toed Ungulates include the hippopotamus and other pigs and the peccaries, the camels and llamas, the deer, the giraffes, and the antelopes, sheep (Fig. 301), and oxen. Excepting the pigs, most of these feed exclusively on plants. The giraffes and antelopes are characteristic of Africa ; but the " mountain goat " of our highest ranges is THE MOUSE AND ITS ALLIES 327 a true antelope, as is also the chamois of Europe. The prong-horn of our Southwestern plains is remarkable in having hollow horns like the antelopes, which are, how- ever, shed like those of the deer. The Odd-toed Ungulates include the horses, tapirs, and rhinoceroses. The horses are remarkable in that they stand upon the toe-nail of the middle digit — all the other digits being rudimentary or absent. While fossil remains of horses are found in all continents, the living species have come from Asia and Africa. The African species are striped (zebras). The tapirs are found living to-day only in South America and southeastern Asia. They frequent the depths of forests near watercourses and feed on leaves and shoots of shrubbery. The rhinoceroses of Africa, of India, of Java, and of the Malay Archipelago are quite distinct. All are large, stupid, and ferocious when attacked, feed on herbage, and wallow in pools. The elephants are distinguished by their long trunks, great incisors (tusks), and huge, complex grinding teeth. The Indian and African types are quite distinct. Ele- phants are intelligent, tractable, and capable of doing much work for man. Their diet is vegetable, consisting especially of the leaves and young branches of forest trees, which they gather with their proboscis. The Insectivora1 are small mammals and chiefly terres- trial. One of our common families includes species of moles which burrow in the ground, have small eyes and broad, shovel -shaped fore feet, used for digging their bur- rows. They feed chiefly on earthworms. The other common family is that of the shrews, which are mouse-like, live chiefly on the surface and in the woods, and feed on insects and small crustaceans. 1 insectum, an insect ; vorare, to devour. 328 ZOOLOGY The Carnivora1 include both land and marine forms. To the first group (Fig. 302) belong the cats (including tigers, lions, leopards, lynx, etc.) ; the civet-cats, mongoose, FIG. 302. — Felis jubata, the Cheetah or hunting leopard. Photo, of a group, in the Field Columbian Museum. etc. ; the hyenas ; the dogs (including jackals, wolves, and foxes) ; the bears; the raccoons; and the great fur-bearers, — martens, minks, weasels, badgers and otters, and skunks. FIG. 303. — Phoca vitulina, the harbor seal. From Parker and Has well, " Manual of Zoology." 1 caro, carnis, flesh ; vorare, to devour. THE MOUSE AND ITS ALLIES 329 Marine Carnivora comprise the seals (Fig. 303), walruses, and sea-lions ; the more valuable of which are disappearing as a result of man's lack of foresight. Altogether, the Car- nivora comprise the most agile, the most intelligent, the most dreadful, and some of the commercially most im- portant of fellow-animals. The Cheiroptera,1 or bats (Fig. 304), are extraordinarily modified mammals, which, like the birds, seem to have FIG. 304. — Synotus, an insectivorous bat. After Vogt and Specht. penetrated into the air to prey on the flying insects. Not all bats are insectivorous, however, for certain Old World bats feed on fruits. Our commonest species are the little brown bats (with a nearly furless wing), and the red bat (with patches of fur on the wing membrane). The Primates2 are of interest because we ourselves are placed in this category together with certain other animals that have attained a less lofty station. The lowest Pri- mates are the lemurs, found chiefly in Madagascar. These have an arboreal habit, and feed on fruits, leaves, and 1 xfLpi hand ; Trre/^p, wing. 2 primus, the first. 330 ZOOLOGY small birds and insects. Next higher come the American marmosets, the howling monkeys, and the flat-nosed, pre- hensile-tailed American apes; still higher are the small- nosed, nonprehensile-tailed apes, including the baboons, FIG. 305. — Simla satyt^us, the orang-utan, in breadfruit tree. From a photograph of a group, in the Field Columbian Museum. mandrills, and macaques. Finally, come the tailless, man- like apes, found exclusively in the Old World — the gib- bons, orangs (Fig. 305), chimpanzee, and the gorilla. The two latter are nearest to man, but one cannot say one is the nearer. For, while the chimpanzee approaches THE MOUSE AND ITS ALLIES 331 man more closely in facial appearance and in intelligence, the gorilla is more man-like in the size and complexity of the brain and in its habit of walking on the ground. There is no reason to doubt that man's species came off from the anthropoid apes ; the recent discovery, in Java, of a fossil form (Pithecanthropus erectus) intermediate between man and the man-like apes, is a strong additional piece of evi- dence. This differentiation of man's species probably began in late tertiary times. APPENDIX TO CHAPTER XX KEY TO THE ORDERS OF MAMMALIA Oviparous; no mammae developed . . . Monotremata Young born prematurely ; reared in marsupium . Marsupalia Viviparous ; no marsupium. hi. Teeth without enamel . . . . Edentata b-2- Teeth with enamel. ci. Hind limbs absent. (9) ; Blattidce (8); Mantidce (8); Phasmidce (7); Acridldce (2); Locmtidce (5); Grillidce, (4). NEUROPTERA, Hexapoda with two pairs of net- veined wings; biting mouth-parts, metamorphosis complete or in- complete: Odonata (9); Ephemeridce (10) ; Termitidce (11); Sialidce. Corydalis (12). HEMIPTERA, Hexapoda with two pairs of wings or none, sucking and piercing mouth-parts, incomplete metamorphosis. [HETEROPTERA], upper wings leathery: Reduviidce (12). [Ho.MOp- 388 ZOOLOGY TERA], wings alike: Cicada (14) ; [here, also, plant lice and animal lice]. DIPTERA : Hexapoda with (typically) one pair wings; pierc- ing and sucking mouth-parts ; complete metamorphosis. [APHANIP- TERA], fleas (71). [PUPIPARA] : Hippoboscidce (71). [BRACHYCERA], true flies : Muscidce (62) ; (EstridcB (65) ; Syrphidce (66) ; Asilidce (66) ; Tabanidce (66); Simuliidce (67). [NEMATOCERA], gnats: Ceci- domyidce (67) ; Culicidce (69) ; Tipulidce (70). COLEOPTERA, Hexa- poda whose fore wings are modified into wing covers ; hind wings folded when not in use : Coccinellidce (55) ; Chrysomelidce (54) ; Cerambycidce (54) ; Curculionidce (53) ; Scolytidce (53) ; Tenebrionidce (52) ; Lampyridce (51) ; Elateridce (51) ; Buprestidce (51) ; Lamelli- cornia (49) ; Lucanidce (49) ; Dermestidce (49) ; Silphidce (48) ; Stap'hy- linidce (47); Hydropliilidce (47); Gyrinidce (46); Dytiscidce (46); Carabidce (45) ; Cicindelidce (45). LEPIDOPTERA, Hexapoda with two pairs of scale-covered wings, sucking mouth-parts, complete meta- morphosis : Tineidce (29) ; Tortricidce (29) ; Pyralidce (29); Geometridce (28); Noctuidce (19,28); Bombycidce (26); Arctiidce (24); Xylotropi- dce (23); Sphingidce (22); Papilionidce (21). HYMENOPTERA, Hexa- poda with two pairs of membranous wings ; biting and licking mouth- parts ; complete metamorphosis: [PHYTOPHAGA], plant-eating (38). [ENTOMOPHAG A] insect parasites (38). [ACULEATA] stinging: For- micidce (34) ; Fossoria (34) ; Vespidce (33) ; Apidce (31). CHORDATA Animals which possess, at some time of life, throat slits and a dor- sal supporting rod or chorda. [HEMICHORDA] Animals of worm-like form, showing gill-slits like fishes. Balano- glossus (251). [TUNICATA] Chordata which are either attached or form colonies or both (251). [VERTEBRATA-ACRANIA] Free-living fish-like Chordata, but without skull, paired fins, or heart, and with colorless blood. Amphioxus (251). SYNOPSIS OF THE ANIMAL KINGDOM 389 [VERTEBRATA-CRANIATA] Free-living Chordata, with skull and complex brain, and red blood. CYCLOSTOMI. Eel-like vertebrates without lower jaw, and living a parasitic life (245). PISCES. Aquatic vertebrates with gills, without lungs, and with paired fins instead of legs. SELACHII, skeleton cartilaginous, no operculum, spiral valve (246). GANOIDEI, skeleton either cartilagi- nous or bony, spiral valve and operculum present : sturgeons (247) ; spoon-bill (247); garpike (248) ; bowfin (248). TELEOSTEI, skeleton bony, no spiral valve. [ACANTHOPTERI], dorsal, anal, and ventral fins with spines, pharyngeal bones distinct : perches (235) ; darters (234) ; sunfishes (235) ; toadfishes (236) ; sculpins (236) ; silversides (236) ; sticklebacks (238). [PHARYNGOGNATHI] fins with spines, pharyngeal bones united. [ANACANTHINI], fins without spines, ventral fins far forward : codfishes (239) ; flatfishes (240). [PHYSOSTOMI], fins with- out spines, ventral fin placed far backward : smelts (230) ; trouts (233) ; whitefishes (234); catfishes (239); suckers (241); minnows (242); pikes (242) ; shads (243); eels (244). [PLECTOGNATHI], intermaxil- laries and maxillaries united. [LOPHOBRANCHII], body covered with bony plates : pipefishes (244). AMPHIBIA (= Batrachia). Vertebrata having no lateral fins (but instead, legs) ; functional external gills during a part of their life. URODELA. Amphibia which retain the tail permanently: Sirenidce (255); Proteidce (257); Amphiumidce (257); Cryptobranchidce (257); Amblystomidce (257); Plethodontidce (259); Desmognathidce (259). Pleurodelidce (254). ANURA, Amphibia which lose the tail in the adult stage : Pipidce (263) ; Hylidce (263) ; Bufonidce (265) ; Ranidce (265). GYMNOPHIONA, Amphibia which have no limbs nor tails; body worm-like. REPTILIA. Vertebrata which breathe exclusively by lungs and whose skin contains horny epidermal scales or bony plates. CHELONIA, trunk enclosed in a bony case : Chelonidce (274) ; Trionychidce (274) ; Testudinidce (275). SAURIA, shoulder-girdle and sternum present, usually with eyelids : Chamceleonidce (272) ; lyuanidce (268) ; Varanidce (269); Lacertidce (270); Helodermidce (270); Anguidce (271). OPHI- DIA, footless scaled reptiles with no shoulder-girdle, sternum, nor 890 ZOOLOGY movable eyelids : Colubridce (276) ; Elapidce (277) ; Crotalidce (277). CRQCODILINA, large reptiles, with longitudinal vent (279). AVES. Feathered Vertebrates. CUKSORES, Aves with keelless sternum (307). NATATORES, swimming birds (305). GRALLATORKS, wading birds (305). GALLINACEI, large ground birds with strong, perching feet and flat nails (304). COLUMBINE, short cloven feet and compressed nails (303). SCANSORES, birds with powerful beak and feet adapted for climbing (299). CYPSELOMOPH^:, cereless birds, with scaleless metatarsus (301). PASSERES, birds whose metatarsus is covered with laminae or scales, usually with singing apparatus : Tyran- nidce (295) ; Alaudidce (295) ; Corvidce (294) ; Icteridce (293) ; Fringil- /iW«(284); Tanagridce (292); Hirudinidce (292); Ampelidce (291); Laniidce (289) ; Vireonidce (288) ; Mniotilidce (287) ; Troglodytidce (287); Certhiidce (286); Paridce (286); Sylviidce (285); Turdidce (285). RAPTORES, birds with cere, hooked bill, and strong, hooked claws (298). PSITTACI, birds with cere, high, hooked beak, and fleshy tongue (parrots, 297). MAMMALIA. Vertebrates which nourish the young by means of milk, and are usually covered with hair. MONOTREMATA, oviparous mammals (321). MARSUPALIA, provided with a marsupium (322). EDENTATA, teeth either absent, rudimentary, or without enamel (323). CETACEA, marine hairless mammals, hind limbs absent (324). UNGU- LATA, hoofed mammals : even-toed ungulates (326) ; odd-toed ungu- lates (327); elephants (327). RODENTIA, canines absent, incisors grow continuously through life (320). CARNIVORA, canines large (328). INSECTIVORA, small, terrestrial, carnivorous mammals, with small canines (327). CHEIROPTERA, mammals with flying membrane between elongated digits (329). PRIMATES, with hands (329). GLOSSARY abdomen, in Arthropoda, the hinder- most of the three divisions of the body, 59. aboral, the side of the body opposite to the mouth, 193. alveolus, a depression, e.g. the socket of a tooth, 280. angulated, forming an angle or sharp corner ; opposed to rounded, 249. antenna, horn or feeler, one of the anterior tactile appendages of Ar- thropoda and Mollusca, 4, 4(3. anterior, situated at the front end of the body. anus, the posterior opening of the food canal. aorta, the main blood-vessel coming from the heart. articular, relating to a joint; the hinge bone of the lower jaw of fishes, 232. atripore, the external opening of the atrium, 249. atrium, or vestibule, a chamber placed either in front of the mouth or, in Chordata, around the gill-slits. auditory clubs, club-shaped sense or- gans on the margin of the bell of jelly-fishes, 221. basihyal, a bone found in fishes, form- ing the base of the U-shaped arch which supports the tongue, 232. bifid, two-parted. bivalve, having two valves or shells, 131, 178. blastula, a stage in the early develop- ment of the egg when it forms a hollow sphere, 193. branchial, relating to the gills. branchiate, bearing gills, 131. branchiostegal rays, the bony rays supporting the membrane below the bones of the operculum in fishes, 232. buccal, pertaining to the mouth cavity or cheeks, 59, 143. byssus, a tuft of tough threads spun from the foot of bivalves and used for attachment to foreign bodies, 180. calcareous, consisting of a calcium or lime compound. calcified, rendered calcareous by depo- sition of salts of lime. callus, a soft substance secreted over a harder bony material, 175. calyx, cup. cambered, concave on the under side, 42. canine, or canine tooth, the pointed tooth situated immediately behind the front cutting teeth, 331. capsule, a little sac containing a fluid. carapace, the thick shell or skin cov- ering the back of Crustacea or Che- Ionia, 103, 280. cardinal, belonging to the hinge, as the teeth of lamellibranch shells, 188. carnivorous, flesh-eating. 391 392 ZOOLOGY cephalothorax, united head and thorax. cere, a waxy sheath at the base of the bill of certain birds, 315. chelicera, the first pair of mouth ap- pendages in the Arachnida, 80. cilia, microscopic, vibratile processes of certain cells. cirrus, a filamentous appendage of the parapodia of Annelida, 159. cleavage, the multiplication of cells at the beginning of the development of the egg, 193, 336. clitellum, a thickened glandular ring sometimes found in the earthworm. coxa, that joint of an Arthropod leg which is nearest the trunk, 59. culmen, the upper ridge of a bird's bill. cuticula, the tough secreted "skin" covering arthropods, hydroids, and other animals. dentary, a bone of the lower jaw of fishes which carries the teeth. dextral, right, applied to right-handed shells, 166. diaphragm, a dividing membrane, 119. elytron, the horny upper wings of beetles, 59. enamel, the hard covering of teeth and some fish scales, 248. encyst, the act of secreting a cyst or vesicle, 227. enteric, pertaining to the enteron or food canal. epidermis, the outermost skin of ver- tebrates; also a superficial horny secretion over the shells of mol- lusks, 175. epimeron, a lateral piece behind the episternum of insects, 59. epiotic, one of the bones surrounding the inner ear in the lower verte- brates, 232. episternum, a piece just lateral to the sternum in the thorax of insects, 59. epistome, in beetles, a piece above the mouth, 59. facetted, composed of numerous small eyes, making up a compound eye, 78. femur, thigh of insects, 59. fertilization, the union of two germ- cells, 335. flagellum, a microscopic, lash-like, vibrating thread of certain Infuso- ria, 226. foliaceous, leaf-like. frontal, applied to a bone of the skull lying between the orbits, 232. gastrolith, a calcareous nodule occur- ring in the stomach of the higher Crustacea, 103. gastrula, a stage in development of the egg just after the digestive cav- ity has been formed, 193. gastrulation, the process of forming the gastrula, 336. gonad, a germ-producing gland, 221. gonophore, a sexual zooid, generally reduced to an exclusively reproduc- tive function, 212. gula, the throat plate on under part of the head of^ insects, 59. hsemal, relating to the blood system. hirsute, hairy, shaggy, 42. hydranth, the " heads " or zooids of a hydroid stock, 210. hyomandibular, a bone which, in fishes, connects the lower jaw with the skull, 232. imago, the adult of an insect. intermaxillary, the same as premaxil- lary. GLOSSARY 393 inter op er cular , the posterio-inferior opercular bone of fishes, 232. jugal, the cheek-bone, 232. keel, a ridge on the breast-bone of birds for attachment of flying mus- cles, 314. labial, pertaining to the labium. labium, the under lip of insects, 59. labrum, the upper lip of insects, 59. lamella, a leaf or plate, 58. lamina, a thin plate. lancet cell, a lancet-shaped cell on the hinder margin of the fore wing of Phytophaga, 43. larva, an immature but active stage of development, 10. ligula, the front edge of the labium, 59. liver area, in crabs, the anterio-lateral area of the carapace in front of the gill region, 123. lumen, the central space of a tube. lunule, a crescentic or heart-shaped area in front of the beak of some bivalve shells, 190. madreporic plate, in echinoderms, a perforated plate admitting water to the system of water tubes, 204. mandible, in arthropods, the most anterior of mouth parts, 59; in vertebrates, the bone of the lower jaw. mantle, the fold of the skin of a mol- lusk, or cirriped, which secretes the shell, 160. manubrium, in jelly-fishes, the mouth stalk, corresponding in position to the clapper of a bell, 211. marsupium, a pouch, in Marsupalia, on the ventral side of the body, 331. maxilla, in Arthropoda, one of the mouth parts immediately following the mandible, 59 ; in vertebrates, a tooth-bearing bone of the upper jaw. maxillary, relating to the maxilla. maxilliped, one of the foot-like mouth parts which in arthropods follow the maxillae. mentum, the front plate of the labium in insects, 59. mesopterygoid, one of the bones form- ing the base of the skull in bony fishes, 232. mesothorax, the middle segment of the thorax, 59. metamerism, the fundamental repeti- tion of parts of the body along the longitudinal axis, as in earthworms 139. metapleure, in Amphioxus, a latero- ventral fin, 249. metapterygoid, one of the bones form- ing the base of the skull in bony fishes and lying behind the mesop- terygoid, 232. metasternum, the ventral plate of the last thoracic segment of insects, 59. metatarsus, in birds, the foot proper, 315. metathorax, in insects, the third or last segment of the thorax, 59. morula, an early stage of egg develop- ment when the germ consists of a nearly solid mass of cells, 336. moult, to change the skin, as in in- sects. myocomma, the thin layer separating two muscle plates in vertebrates, 246. myomere, a muscle plate, 246. nasal, belonging to or forming the nose, as nasal bones. neural, pertaining to the nervous system. 394 ZOOLOGY neural groove, the groove which marks in the vertebrate embryo the devel- oping central nervous system, 261. nodulous, covered with nodules or little lumps, 175. notochord, the axial supporting rod of chordates, 249. (jesophayus, the gullet, the part of the food canal leading to the stomach. operculum, in gastropods, the horny plate which closes the aperture ; in fishes, the gill-cover, 232. oviduct, the duct which carries eggs from the body, 120. oviposit, to lay eggs, as in insects, 53. palatine, of the palate or roof of the mouth ; name of a pair of bones forming the palate, 232. pallial line, streak formed in a bivalve shell by the margin of the attached mantle. pallial sinus, an incurving of the pal- lial line to receive the siphon in cer- tain lamellibranchs. palp, a secondary sensory outgrowth of a mouth part of an insect, 59. paraglossse, a pair of small appendages of the under lip of insects, 59. parapodia, the paddling feet of poly- chsetes, 147. parasitic, living on the nutritive juices elaborated by another organism. parasphenoid, a bone occupying the base of the skull, 267. parietal, bones of the middle upper part of the brain case, 232. pectinate, comb-like. pectoral, of the chest ; the chest limbs of fishes, 246. pedicellariee, minute forceps-like or- gans found on some echinoderms, 194. pelvic Jin, or ventral fin, the hinder paired appendages of fishes, 246. penultimate, next to the last. percoid, like a perch. perisarc, the outer tough skin of hy- droids, 211. pharynyeal, relating to the pharynx or throat, 252. polyp, the sessile form of coelenterates. posterior, situated behind. premaxilla, the most anterior tooth- bearing bone of the upper jaw of fishes, 232. preopercular, the most anterior of the bones of the operculum of fishes, 232. primaries, the large feathers on the distal joint of a bird's wing, 315. proboscis, in insects, a sucking tube connecting with the mouth, 61. prosternum, the most anterior of the ventral platesMn the thorax of in- sects, 59. prostomium, in worms, a lobe of the body projecting above and in front of the mouth. prothorax, the most anterior of the segments of the thorax of insects, 59. pseudobranch, in fishes, a rudimentary gill in front of the first throat slit, 231. pseudopodia, retractile processes in Protozoa. pterotic, one of the ear bones of fishes, 232. pteryyoid, a bone of the base of the cranium, 232. pupa, a stage in insect development preceding the imago, 11. quadrate, a bone lying between the skull and the hinge of the lower jaw in fishes, 232. GLOSSARY 395 radii, lines proceeding from a common centre like the spokes of a wheel, 86. ramus, a branch or projecting process, 131. rictus, the corners of the mouth in birds, 315. rostrum, beak, the frontal process of crustaceans. scansorial, capable of climbing, 315. scutellate, composed of plates, 315. scutellum, the third of the four pieces composing the upper part of a tho- racic segment of an insect, 59. septa, the radial calcareous plates of a coral, 215. sinistral, left. siphon, the drawn-out edges of the mantle folds of lamellibrauchs, 183; the strand penetrating the chambers of the Nautilus shell, also called siplmncle, 173. spatulate, shaped like a spatula, or a paddle. sphenotic, one of the bones forming the ear capsule of fishes, 232. spinnerets, the tubercles through open- ings in which the spider thread is spun, 84. spiracle, one of the openings to the air-tubes of insects, 59. spurious, not genuine. squame, a scale in decapods attached to the antenna, 124. sternum, in vertebrates, the breast- bone, 280; in insects, the ventral part of a somite, 59. stiamata, spiracles'. stock, colony, 207, stolon, a runner from which zooids bud, 220. subopercular, the lowermost bone of the operculum in fishes, 232. suborbital, a bone in fishes, lying below the eye, 232. supraethmeoid, a bone of the nose in fishes, 232. supraoccipital, a bone forming the upper part of the back of the head. suture, a seam or structural line, 70. syinplectic, a bone uniting the quad- rate to the bones suspending the lower jaw, 232. tarsus, the jointed foot of an arthro- pod leg, 59. telvon, the tail-piece of a crustacean, 116. tentacle, a projecting tactile organ. thoracic, pertaining to the thorax or chest. tibia, the joint of an insect's leg next above the tarsus, 59. trachea, one of the respiratory tubes of insects, 64. trochanter, a joint of the insect leg lying distal to the coxa, 59. umbilicus, a depression in the centre of the base of many spiral sbells, 175. umbones, a protuberance just above the hinge of a bivalve shell, 188. velum, a circular membrane extend- ing like a shelf from the margin of the jelly-fish bell, 211. viviparous, giving birth to well-de- veloped progeny, 331. INDEX Aardvark, 323. Abnormalities, lobster, 119; plana- rians, 155; starfish, 196. Acanthocottus, 236. Acanthopteri, 252. Acarina, 95. Acartia, 128. Accipiter, 298. Acineta, 225. Acipenser, 247. Acmaea, 170., Acmaeidae, 177. Acrania, 252. Acrididje, 1, 15. Actitis, 306. Adalia, 56. Adeorbidse, 175. Admiral, 21. ^schna, 10. Agalena, 90. Agricultural ant, 37. Alaudidas, 259, 317. Alligator, 279. Allolobophora, 114. Alosa, 243. Amblystoma, 257, 335. Amblystomidse, 257, 267. Ameiurus, 240. American crossbill, 284. Amia, 248. Ammonites, 173. . Amoiba, 227, 229. Ampelidae, 291, 317. Ampelis, 291. Amphibia, 254; distribution of, 255; metamorphosis of, 260. Amphioxus, 249, 252. Amphipoda, 112. Amphitrite, 149, 150, 159. Amphiuma, 198. Amphiumidse, 257, 266. Amphiura, 198. «. Anacanthini, 253. Anatis, 56. Ancestry of vertebrates, 248. Angle wings, 21. Anguidse, 271. Annelida, 136. Anodonta, 191 ; embryo of, 180 ; food of, 178 ; habitat of, 178. Anolis, 268. Anomiidae, 191. Anthremis, 48. Ant-eater, 322. Antelopes, 326. Anthophagus, 47. Ants, 30, 34, 43; army, 37; colonies of, 35 ; intelligence of, 35 ; language of, 36 ; leaf-cutting, 37 ; social life of, Anura, 255, 262, 266. Apes, 230. Aphaniptera, 61, 70. Aphids, 14. Aphrodite, 148. Aphroditidae, 159. Apidae, 31, 42. Aplysia, 164. Apteryx, 307, 308. Arachnoidea, 92. Arbacia, 200. Area, 184. Archaeopteryx, 314. Arched crabs, 123. Archiaster, 195. Arcidae, 184. Arctiidae, 24, 41. Araneina, 80, 95. Argiope, 80-83, 86; 397 distribution of, 398 ZOOLOGY 83 ; food of, 82 ; spinning habits of, 82. Argonauta, 172. Arion, 162. Ark shells, 162. Armadillo, 323. Army ants, 37. Army worm, 28. Arthrogaster, 92. Ascaris, 151. Asilidaa, 66. Asiphonata, 178. Asp, 277. Asparagus beetle, 56. Assassin bug, 12. Astacidse, 124. Astacus, 97-99, 113. Astartidae, 190. Asterias, 197 ; distribution of, 192, 197. Asteriodea, 197, 203. Astrangia, 216. Atoll, 217. Attus, 91. Auriculidae, 161, 166, 176. Autolytus, 147, 159. Aviculidae, 185. Axolotl, 258, 260. B Baboon, 330. Badger, 328. Balauinus, 53. Balanoglossus, 250, 251. Balanus, 129. Bald eagle, 298. Baltimore oriole, 293. Banded horse-fly, 66. Bark-borer, 53. Barnacles, 102 ; habits of, 129. Barn-swallow, 292. Barrier reef, 217. Bat, 329 ; food of, 329. Batrachia, 254. Batrachus, 236. Bears, 328. Beaver, 310. Beaver parasite, 5(5. Bee-moth, 29. Bees, 30, 31, 42 ; swarming, 32. Beetle, 44; development of, 44; eco- nomic importance of, 57; food of, 56; larval habits of, 45; number of species of, 45. Bell-hydroid, 209. Belted kingfisher, 300. Birds, 281; economic importance of, 311 ; extinct, 313; flight of, 310; pro- tection of, 312; migration of, 309; teeth of, 314. Bird's-nest, edible, 303. . Bittern, 305. Black-fly, 66. Black lobster, 103. Black moccasin , 279. Black snake, 276. Blattidae, 8, H. Blister-beetle, 57, 61. Blow-fly, 61. Blue, 22. Bluebird, 285. Bluejay, 295. Boa, 276. Bobolink, 294. Boll-worm, 28. Bombus, 31. Bombycidae, 24, 42. Bombyx, 24. Bonasa, 304. Bony fishes, 252. Bosminid*, 131. . Bot-flies, 64, 72. Botryllus, 250. Bougainvillea, 211. Bowfin, 248. Box tortoise, 275. Brachiopoda,.l27, 130. Brachycera, 61, 63. - . Brachyura, 107. Branchipus, 127, 130. Brittle-stars, 198. Brook sucker, 241. Brown creeper, 288. Bruchidae, 57. Bryozoa,141, 217. Buccinidae, 175. Buck-beetles, 54.- Budding, 217. Buffalo gnat, 66, 72. INDEX 399 Bufo, 264. Bufonidae, 265. Bngula, 142. Bull-frog, 2(56. Bull-head, 241. Bullidfe, 174. Bumblebee, 31. Buprestidae, 51, 60. Buprestis, 51. Buthus, 93. Butterflies, 41 ; broods of, 17 ; habits and food of, 16 ; mimicry of, 18-21 ; polymorphism of, 17; protective resemblance of, 18-21. Cabbage butterfly, 18. Callianassa, 105. Gallinectes, 109. Calosoma, 46. Calyptraeidae, 177. Cambaroides, 99. Cambarus, 99, 100, 113. Camels, 326. Campanularian hydroids, 210. Campanularidae, 209, 221. Camponotus, 35. Canada grouse, 304. Cancer, 114. Carabidje, 45-46, 60. Carchesium, 224; food of, 225. Cardiidae, 190. Cardinal grosbeak, 285. Carididae, 124, 180. Carolina paroquet, 297. Carnivora, 328, 331. Carpenter ant, 35. Carrion-beetles, 48, 57, 60. Carrion-fly, 73. Case-bearers, 29. Cassowary, 307. Catfishes, 239, 253;-Tange of, 239-240. Catocala, 19, 28. Catometopa, 123. Caudina, 201, 203. Caviare, 247. Cecidomyidae, 66, 68. Cedar-bird, 292. Cedar waxwing, 291. Centipedes, 74. Centrurus, 93. Cephalopoda, 171. Ceratodus, 249. Cerambycidae, 54, 5(5, 61. Cerebratulus, 158. Cerithia, 288. Certhiidae, 286, 316. Cestoda, 386. Cetacea, 324, 331. Ceuthophilus, 6. Ceryle, 300. Chameleo, 272. Chameleon, 272. Cheetah, 328. Cheiroptera, 329, 331. Chelidon, 392. Chelonia, 273, 280. Chelonidte, 274. Chestnut-sided warbler, 288. Chewink, 285. Chigger, 95. Chigoe, 71. Chilopoda, 74; food of, 74. Chimney-swift, 302 : nest of, 302. Chimpanzee, 330. Chipping-sparrow, 235. Chiton, 171. Chlorops, 72. Choloepus, 324. Chordata, 388. Chrysomelidae, 57, 61. Chrysops, 6(3. Cicada, 13; pupal case of, 13. Cicindela, 45. Cicindelidae, 45. Ciliata, 229. Ciona, 250. Cirratulidae, 159. Cirratulus, 149, 159. Cirripedia, 131. Cistenides, tube of, 150. Citheronia, 25-26 ; larvae of, 25. Citig-radse, 89, 96. Civet-cats, 328. Cladocera, 127, 131. Clam, 178. Claws, abnormal, of lobster, 120. Clepsine, 140-141. 400 ZOOLOGY Click-beetle, 61. Clisiocampa, 26, 27. Clothes-moths, 29-30. Clymenella, 150-159. Clypeaster, 201. Cnidaria, 205 ; fresh-water, 207. Cobra, 277. Cobweb spiders, 80. CoccinellidfE, 55, 61. Cockatoos, 297. Cockroaches, 8, 14. Codfishes, 253 ; habitat of, 239. Coslenterata, form of, 205. Colaptes, 301. Coleoptera, key to families, 58-61; terminology, 59. Colonies, of ants, 35 ; formation of, in Cnidaria, 217-218. Cojumba, 304. Columbellidae, 176. Cqlumbidae, 303. Columbinae, 314. Columbridae, 276. Condor, 298, 299. Congo snake, 256 ; habitat of, 257. Con urns, 297. Cooper's hawk, 299. Cqpepoda, 127, 131. Copperhead, 279. Copris, 50. Coral cup of Manicina, 216. Coral, polyps, 215-216 ; reefs, 216- 217. Coregonus, 233. Cordylophora, 207-208. Corvidse, 294, 316. Cotton-worm, 28. Cow-bird, 293; Crab's eyes, 104. Crab spider, 89, 90, 96. Crane-flies, 68-69, 73. Cranes, 305. Craspedosomidae, 79. Crassatellidae, 190. Crayfish, 97, 122 ; development of, 117 ; edible, 113; food of, 98; moulting of, 103, subfamilies of, 98-99. Creepers, 286. Crepidula, 169-170, 177. Cribrella, 196-198. Crickets, 4-5, 15. Cricket-grasshopper, 6. Crinoidea, 203. Crocodile, 279. Crocodilina, 279-280. Crossbills, 285. Crotalidae, 277-278. Croton bug, 8. Crow, 294. Crow-blackbird, 293. Crustacea, 97, 104, 125. Cryptobranchidae, 257, 266. Cryptobranchus, 258. Ctenophora, 219-220. Cuckoos, 299 ; laying habit of, 300. Culex, 68. Culicidse, 68. Cumacea, 122. Curculionidae, 53, 61. Cursores, 306, 315. Cuttlefishes, 172. Cyanocitta, 295. Cycladidae, 180, 191. Cyclas, 191 ; habitat of, 180 ; distribu- tion of, 180-181. Cyclometopa, 123. Cyclostomi, 252, habits of, 245 ; para- sitic on fishes, 245-246. Cyclops, 127-128. Cyllene, 54-55. Cypselomorphae, 301, 315. D Daddy-long-legs, 93. Daphnia, 97, 125; food of, 126; effect of temperature on, 127. Daphnidae, 131. Darcus, 49. Darters, 234, 252 ; habitat of, 234. Decapoda, economic importance of, 111 ; eyestalks of, 121. Deer, 326. Degenerate flies, 70. Dendroctonus, 53. Dermestidae, 48, 49, 61. Dero, 137, 144. Desmognathidae, 259, 267. INDEX 401 Desmognathus, color of, 259; habitat of, 2GO. Development, of beetle, 44; crayfish , 117 ; edentates, 333 ; effect of heat on, 333; effect of light on, 333; of egg, 115: frog's egg, 332; fly, 62; general laws of, 335 ; grasshopper, 3-4 ; lobster, 115-117 ; Spelerpes, 261- 262; starfish, 193-194; Urodela,261. Diapheromera, 7. Didelphys, 323. Diemyctylus, 267; food of, 254; hab- itat of, 254 ; life history of, 254-255. Digger wasp, 34, 43. Diplocardia, 143. Diplopoda, 74. Dipnoi, 248, 252. Diptera, 61, 63, 72; injurious to man, 71; scavengers, 72; short-horned, 63; source of disease, 71. Discontinuous genera, 99-100. Distomum, 155. Divers, 60, 306. Division of labor in Cnidaria, 219; physiological, 120. Dodo, extermination of, 314. Dogs, 328. Dogfish, 246. Dolphins, 324. Doryphora, 55. Downy woodpecker, 301. Dragon-fly, 9-10. Duckbill, 322. Duck-bill catfish, 247. Dytiscidae, 46, 56, 60. Dytiscus, 47, 138. E Eagles, 298. Earwigs, 9. Earthworm, 132-134; economics of, 135; food of, 134; habits of, 132; regeneration of, 134; relationships of, 132 ; resistance of, 134. Echidna, 322. Echinarachnius, 201. Echinoidea, 322, Echinoids, 204. Echiurus, 139. Economic importance, of beetles, 57; birds, 311; decapods, 111; earth- worms, 135; parasitic worms, 158; protozoa, 228; slugs, 162; starfish, 193; smelt, 230. Ectopistes, 304. Ectoprocta, 143. Edentata, 323, 331. Edentates, discontinuity of, 323. Edible, birds' nests, 303; Carididse, \114; crabs, 108-109, 113; crayfish, 113 ; lobsters, 113. Eels, 253; description, distribution, reproduction, 244. Egg, fertilization, 336 ; masses of tent caterpillar, 26; nauplius, 115. Egrets, extermination of, 305. Elapida3, 277. Elaps, 277. Elateridse, 51, 61. Elephants, 327. Endoprocta, 143. Enemies of lobster, 102. English sparrow, 281; food of, 282; spread of, in America, 281-282. Engraver beetles, 61. En sis, 182. Entomophaga, 43. Entomostraca, 97, 125. Eolis, 171. Ephemeridae, 10. Epiera, 80 ; web, 87. Erycinidse, 190. Euglena, 225-226, 229. Euglycera, 146, 159. Eunicidae, 159. Eupagurus, 106. Eupomatis, 235. Eutamia, 276. Even-toed ungulates, 326. Exotic species, increase of, 283. Extinct birds, 313. Eyestalks of decapods, 121. Falcons, 298. Fasciolariidse, 175, 177. Felis, 328. Fiddler crabs, 110, 123. 402 ZOOLOGY Fireflies, 51-52, 58, 60. Fishes, 230. Fissurella, 170. Fissurellidae, 177. FlageUata, 225, 229. Flatfishes, 239-240, 253. Flatworms, 153. Fleas, 61,70. Flicker, 301. Flies, 61 ; degenerate, 70 ; development of, 62; food of, 62; plant-infesting, 72 ; mimicry in, 65 ; parasites of, 63 ; parasitic, 70; trachea of , 63. Flight of birds, 310-311. Flycatchers, 295. Food of, beetles, 56; butterflies, 16; crayfish, 98; earthworm, 134; fly, 62 ; hydra, 207 ; mouse, 319 ; English sparrow, 282; starfish, 193; whale, 325. Forficulidae, 9. Formicidje, 34-35, 43. Fossil, birds, 314; lizards, 272; man, 331. Fossoria, 34, 43. Fowls, origin of, 305. Fox-sparrow, 285. Fresh- water clam, 178. Fresh-water Cnidaria, 207. Fresh- water jelly-fishes, 208. Fringillidge, 284, 317. Fringing reefs, 217. Fritillaries, 22. Frog, development of, 333; postem- bryonic development of, 334. Frog's egg, development of, 332 ; heal- ing of, 334; regeneration of, 334; size of, 332. Fulgur, 168, 169, 175. Fundulus, 242. G Gadus, 239. Ganoidei, 247-252. Ganoids, 252. Garpike, 248. Garter snake, 276. Gasterosteus, 237-238. Gastropoda, 160, 161. Gall-gnats, 66, 72. Gall-flies, 31. Gall-producing Hymenoptera, 43. Gall-wasps, 31, 38-39. Galls on plants, 67. Galley-worm, 76. Gallinacei, 304, 314. Gallus, 305. Gebia, 105. Geese, 306. Gelasimus, 110-111. Genera, discontinuous, 99-100. General laws of development, 335. Geometridae, 28, 42. Geomys, 320. Geophilus, 76. Geothlypis, 289. Gephyrea, 138-139, 141. Germ theory of Infusoria, 223. Gibbons, 330. Gila monster, 270-271. Giraffes, 326. Glossina, 65. Glow-worm, 271. Glyceridse, 159. Gnats, 61. Goat-suckers, 301, 303. Golden-crowned kinglet, 287. Gopher, 320. Gorilla, 330. Grallatores, 305, 314. Grapta, 21. Grasshopper, 1-4 ; development of, 3-4. Grass spiders, 90. Gray- veined white, 18. Great horned owl, 299. Great northern shrike, 290. Green frog, 266. Grillidfe, 4-5, 15. Grillus, 5. Ground-beetles, 45-46. Grouse, 304. Gryllotalpa, 5. Guinea fowl, 304. Gulls, 306. Gymnophiona, 255, 266, 389. Gypsy moth, 28. Gyrinidae, 46, 60, INDEX 403 H Habitat, of Auodonta, 178; butter- flies, 16; Daphnia, 120; earthworms, 132 ; Hydra, 205 ; slug, 161 ; Unio, 178. Habits, of Acrididae, 1; mouse, 319; rat, 319. Hadrosaurus, 273. Hair streaks, 22. Hairy ant-eater, 323. Hairy woodpecker, 301. Halistemraa, 213. Hard-shelled clams, 190. Hares, 321. Hawkbill-turtles, 274. Hawk-moths, 22, 41. Hawks, 298. Heating of frog's egg, 334. Heat, effect on development, 333. Helicidae, 161. Helix, 161-165 ; introduction of nemo- ralis, 164 ; variations in, 164. Hellbender, 257, 258. Heloderma, 270, 271. Hemiptera, 12, 67. Hen clams, 189. Hermit crabs, 105, 107, 123. Herons, 305. Hessian-fly, 67,68, 82. Hesperornis, 313. Heterandria, 242. Heteroptera, 12. Heterotricha, 224, 229. Hippa talpoides, 107. Hippidas, 107, 123. Hippoboscidae, 70. Hippopotamus, 326. Hirudinidse, 292, 316. Holothurians, 201. Holothuroidea, 204. Holotrichia, 229. Homarus, 100, 113. . Homoptera, 13-14. Honey bees, 32-33. Horn-pout, 241. Horned corydalis, 12. Horned fly, 72. Horned toad, 269. Hornet, 34. Horses, 327; fossil, 327. Horse-flies, 65, 72. House-fly, 61. House wren, 288. Humming-birds, 301. Hydra, 205, 335; description of, 205- 207; food of, 207; habitat of, 205; regeneration of, 219. Hydractinia, 209. Hydrocorallidte, 208, 220. Hydroidre, 220. Hydromedusse, 212, 220. Hydrophilidse, 60. Hydrophilus, 47. Hydrozoa, 220. Hyenas, 328. Hygrotrechus, 12. Hylidae, 263. Hymenoptera, 30, 72; gall-producing, 43 ; parasitic, 38, 43 ; plant-eating, 43. Hypotricha, 229. Ichneumon flies. 30. Icteridae, 293, 317. Idylia, 219. Iguanidse, 268-269. Importation of mouse, 318. Increase of exotic species, 283. Indigo bird, 285. Infusoria, 222, 229. Insectivora, 327, 331. Intelligence of ants, 35. Iphiclides, 18. Isopoda, 112. J Jay, 294. Jelly-fishes, fresh-water, 208 ; life his- tory of, 210 ; salt-water, 208. Jigger, 71, 95. Jingle shells, 191. Julidae, 79. Julus, 76, 77, 79. Jumping mice, 321. Jumping spiders, 90, 91, 96, 321. June-bugs, 50. Kallima, 20. Katydids, 6, 15. K 404 ZOOLOGY Key to classes of Echinodermata, 203 ; principal families of Acrididae, 2; Coleoptera, 58-61 ; Hymenoptera, 42-43 ; Lamellibranchiata, 188 ; Lepi- doptera, 41-42; Myriapods, 78; Or- thoptera, 14; Polychaeta, 159; Pul- monates, 161 ; principal genera of Daphnidae, 126; Lamellibranchiata, 191 ; to genus Lithobius, 79 ; to chief orders of Birds, 314-317; Entomos- traca, 130; Gastropoda, 160; Mala- costraca, 122 ; species of Earthworm , 143 ; of Lithobius, 79. Killer whale, 325. Killifish, habits, food of, 242. Kingbird, 296. Kingfisher, 1300. Kitchen-middens, 188. Lacerta, 270. Lacertidae, 270. Lachnosterna, 50. Ladybird beetles, 55, 61. Lamellibranchiata, key to families of, 188. Lamellicornidae, 58. Lamellicorn beetles, 49-50, 58 ; leaf- eating, 50 ; scavengers, 50. Lamprey, 245. Lamprey eels, 252. Lampyridae, 51, 60. Land-locked fishes, 230. Language of ants, 36. Laniidae, 289, 316. Lanius, 290. Larks, 295. Larval habits, of beetle, 45; grass- hopper, 3-4 ; lobster, 116. Laterigradae, 89, 96. Leaf beetles, 61. Leaf-cutting ants, 37-38. Leaf-eating lamellicorns, 50. Leaf-hopper, 44. Leaf-miners, 42. Leaf-rollers, 42. Lecanium, 13. LedidaB, 187, 188, 191. Leeches, 139-140. Lemurs, 329. Leopards, 328. Leopard frog, 266. Lepidonotus, 147-148, 159. Lepidosteus, 248. Libinia, 108. Life history, of mosquito, 68 ; Union* idae, 179-180. Light, effect of, on development, 333. Limacidae, 161. Limacinidae, 177. Limax, 161-164. Limnaea, habitat of, 166. Limnaeidae, 161. Limpets, 170, 177; economic impor- tance of, 170. Limulus, 114. Line-weavers, 87, 96. Liobunum, 93-94. Lions, 328. Lithobiidae, 78. Lithobius, 74, 75, 78, 79. Littorina, 167-168, 175; littoria, intro- duction, 167 ; range, 167 ; spread, 283. Littorinidae, 175. Liver-flukes, 153-154; life history of, 154-155 ; stages of, 156. Lizards, 268 ; fossil, 272. Llamas, 326. Lobster, 100, 103, 113; abnormalities in, 119; development of, 115; em- bryos of, 116 ; enemies of, 102 ; moult- ing of, 103 ; protection of, 102. Locust borer, 55. Locusts, 14, 15 ; of old world, 2. Locustidae, 1, 15. Loligo, 172. Long-horned beetles, 54. Long-horned grasshoppers, 15. Long-horns, 61. Lophobranchii, 244, 253. Lost parts, regeneration of, 118. Louse-fly, 70. Loxia, 284. Lucanidae, 49, 58. Lucanus, 49. Lucius, 243. Lumbriculidae, 144. INDEX 405 Lycaenas, 22. Lycosa, 91. Lycosida, 92. Lynceidae, 131. Lynx, 328. M Macaque, 330. Macrodactylus, 50. Macrolepidoptera, 22. Mactra, 183. Mactridae, 182, 189. Maggots, rat-tailed, 65. Malacostraca, 97, 111, 125. Maldanidse, 159. Mammalia, 318, 331. Manatee, 324. Mandrills, 330. Mantidae, 8, 14. Margaritana, 191. Marmosets, 324. Marsupalia, 322, 331. Martens, 328. Maryland yellow-throat, 288, 289. May beetles, 50. May-flies, 10. Meadow grasshopper, 6. Meadow-lark, 293. Meal-beetles, 61. Meal-worms, 52. Mealy bug, 14. Measuring-worms, 42. Medusa, 211. Megascops, 298. Melampus, 161, 176. Melanoplus, 2. Meloidae, 61. Melophagus, 70. Metacrinus, 202. Metallic wood-borers, 51, 60. Metamorphosis, of Amphibia, 260 ; Ano- donta, 180; beetles, 44; crayfish, 117; dragon-flies, 9; fly, 63; frog, 335 ; Hemiptera, 12 ; Lepidoptera, 16 ; liver-fluke, 152 ; lobster, 116 ; Neu- roptera, 11 ; Orthoptera, 1 ; starfish, 194. Metridium, 214, 215. Microhydra, 208. Microlepidoptera, 22. Midgets, 62. Migrations of birds, 309. Milk-snake, 276. Mimicry, 18-21 ; flies, 65. Minks, 328. Minnows, 242, 253. Minyas, 214. Mniotilidse, 287. Mocking-bird, 287. Modiola, 185. Mole crabs, 123. Mole cricket, 5. Mollusca, 160, 178. Monarch, 22. Mongoose, 328. Monkeys, 330. Monotremata, 321. Morone, 234. Morula, 336. Mosquito, 68. Motacillidae, 317. Moths, 22. Moulting, 103. Mourning cloak, 21. Mouse, distribution of, 318 ; food of, 319 ; habits of, 319 ; importation of, 318. Mud-daubing wasp, 82. Mud eel, 255, 256. Mud fishes, 252. Mud puppy, 257. Mud wasps, 34, 43. Muricidae, 169, 175. Mus, 321. Muscidae, 61, 64, 72. Muskallunge, 242. Muskrat, 321. Musk turtle, 276. Mussels, 120, 190. Mustelus, 246. My a, 182, 183. Myidaa, 182, 189. Myrmica, 37. Mytilidge, 184, 190. N Naidae, 144. Nais, 137-138, 144. Narcomedusae, 221. 406 ZOOLOGY Natatores, 305, 3U. Natica, 168, 175. Naticidse, 175, 170. Nautilus, 173. Nebalia, 122. Necturus, 257, 335. Nemathelminthes, 386. Nematocera, 61, 66. Nematus, eggs of, 40. Nemertini, 158. Nephelis, 140. Nereida, 159. Nereis, 136, 138, 145, .146, 159; food and habitat of, 145. ' Nest, of barn-swallow, 292; of chim- ney-swift, 302 ; of pewee, 296. Neuroptera, 11-12. Newts, 254, 362; how to capture, 255. Night-hawk, 303. Nightingale, 285. Nile varan us, 269. Noctuidae, 27-28, 41. Norwegian lobster, 113. Notodelphys, 263. Notolophus, 28. Nuculidae, 191. Nuthatches, 286. Nymphs, 21. O Obelia, 210. Odd-toed ungulates, 327. Odonata, 9. (Estridae, 64. Oligochaeta, 132, 136, 139. Oniscus, 112. Operculum, of worms, 151 ; of fish, 233. Ophidia, 280. Ophion, 39. Ophiuroidea, 198, 203. Opisthobranchiata, 161. Opisthobranchs, 164, 170-171; degen- eration of shell of, 162. Opossum, 322-323. Orang-utan, 330. Orbitelariae, 86, 96. Orb-weavers, 86, 96. Orbweb, diagram of, 86; of Epiera, 87 ; nomenclature of parts of, 86. Orbweb spiders, 80. Orca, 325. Orchard oriole, 293. Orchelium, 6. Ornithorhynchus, 321. Orthoptera, 1. Orthosoma, 54. Osmerus, 230. Ostracoda, 127, 131. Ostrea, 187. Ostreidae, 190; economic importance of, 187. Ostrich, 307; habits of, 307-308. Otter, 328. Owlet moths, 27-28, 41. Owls, 298. Oxen, 326. Oxyrhyncha, 123. Oyster drill, 169. Oysters, 187-188, 190. Paddlefish, 247. Paguridse, 105, 123. Painted turtle, 276. Palaeinonetes, 104. Paliuurus, 101. Pallene, 95. Palm-crab, 107. Pandoridae, 189. Pandorus, 23. Panopeus, 109. Papilionidae, 41. Papilio, 21. Paramecium, 222, 229; food of, 224; fusion of, 229; habitat of, 224; rate of division, 229. Parasites of fly, 63. Parasitic, flies, 70; Hymenoptera, 43; worms, 158. Paridaj, 286, 316. Parrots, 297. Partridges, 304. Passenger pigeon , 303. Passer, 281-282. Passeres, 315. INDEX 407 Patella, 170. Pauropus, 77. Pearl-bearers, 185 ; fishery, 185-18(5. Peccaries, 326. Pecten, 186. Pectiuatella, 143. Pectinidse, 190-191; locomotion of, 186. Pedicellina, 141. Pelicans, 306. Perches, 235, 252. Peritricha, 229. Petrels, 306. Petricolidae, 189. Petromyzon, 245. Pewee, 296 ; nest of, 296. Pheasants, 304 ; range of, 305. Phalangina, 93. Pharyngognathi, 93. Phasmidse, 7, 15. Phasmomantis, 8. Philampelus, 23. Philinidje, 176. Phoca, 328. Pholadidje, 181, 188. Pholis, 237. Photuris, 52. Phrynosoma, 269. Physa, 161, 167; food of, 166; habitat of, 166. Physalia, 213. Physiological division of labor, 120. Physostomi, 253. Phytophaga, 43. Pickerels, 242. Pickerel frog, 266. Pieris, 21 ; rapse, increase and spread of, 283. Pigeons, 304. Pigs, 3136. Pike, 242. Pimpla, 37. Pin worm, 153. Pine borers, 53. Pinnotheres, 109-110. Pipa, 262 ; with embryos, 263. Pipe-fishes, 244, 253. Pipidse, 263. Piranga, 293. Piroplasma, 228. Pisidium, 191. Pithecanthropus, 331. Planarians, abnormalities of, 155; fresh-water, 153; regeneration of, 154. Planorbis, 167; eggs and habitat of, 167. Plant-eating hymenoptera, 43. Plant galls, 67. Plant lice, 14. Platyonichus, 110. Platypsylla, 56. Plectognathi, 253. Plethodon, 259. Plethodontidse, 259, 267. Pleurodelidse, 267. Pleurotomidse, 176. Plovers, habitat of, 305. Plumatella, 142. Plume-moths, 42. Podophora, food and habitat of, 225. Podopthalmata, 122. Poisonous spiders, 91-92. Polistes, 33. Polychseta, 136, 148. Polycirrus, 149-150. Polydesmidse, 79. Polydesmus, 77, 79. Polymorphism in butterflies, 17. Polyphemidse, 131. Polyxenidse, 78. Polyzoniidse, 79. Pond snail, habitat of, 166. Portuguese man-of-war, 213-214. Postembryonic development of frog, 334. Pouched gopher, 320. Prairie dog, 320. Prawns, 104, 124. Praying-mantis, 8, 14. Primates, 329, 331. Prionus, 54. Prosobranchiata, 160. Protection, of birds, 312; of lobster, 102. Protective resemblance, 18-21. Proteidae, 257, 266. Protozoa, 222; relations to man, 228; reproductive capacity of, 228. 408 ZOOLOGY Psammobiidse, 189. Psittaci, 297, 315. Psoroptes, 94. Pterophoridae, 42. Pulex, 70. Pulmonata, 160, 161, 164, 165; aquatic, 166. Pumpkin-seed sunfish, 236. Pupa, 16, 165. Pupidse, 385. Pupipara, 61. Purple grackle, 294. Pyralidse, 29, 42. Pyramidellidse, 174. Quail, 304. Quadrate, 232. Quiscalus, 294. Q Raccoons, 328. Races of tame mice, 319-320. Rails, 305. Rana, 265. Ranida3, range of, 265. Raptores, 298, 315. Rat, habits of, 319. Rat-tailed maggots, 65. Rattlesnake, 278. Rays, 252. Razor clams, 188. Razor shell, 182. Red-eyed vireo, 289-290. Red-headed woodpecker, 301. Reefs: barrier, coral, fringing, 217. Redpoll warbler, 288. Red-winged blackbird, 293. Reduvius, 12. Regal moth, 25. Regulus, 287. Regeneration, of earthworms, 134; flat worms, 153 ; frog's egg, 334 ; Hydra, 219 ; lost parts of lobster, 118 ; plan- arians, 154. Relationships of earthworms, 132. Reproductive capacity of protozoa, 228. Reproduction, 332. Reptiles, 268. Resistance of earthworms, 134. Retitelariae, 87, 96. Rhea,307. Rhinoceroses, 327. Rhizopoda, 229. Rice bird, 294. Rissoida3, 174. Robber-flies, 65, 72, 73. Robin, 285. Rock-eel, 236, 237. Rodentia, 320, 331. Rodents, 320. Rose-breasted grosbeak, 285. Rose-bug, 50-51. Round worms, 151. Routes of bird migration, 309. Rove beetles, 47, 57, 58. Ruby-crowned kinglet, 285. Ruby-throated humming-bird, 302. Ruffed grouse, 304. Runners, 60. Running beetles, 45. Running spiders, 91, 96 ; habits of, 89= Salmo, 233; skull of, 232. Salmonidae, 230, 231 ; distribution of, 231 ; spawning of, 231-233. Salamander, 259. Saltigradfe, 90, 96. Sand dollars, 200-201. Sandpipers, 305. Sauria, 268, 280. Saw-fly, eggs of, 40 ; larvae, 39. Saxicavidae, 189. Saxicolidae, 315. Scalariidae, 174. Scale bug, 14. Scale insect, 13. Scaled worm, 148. Scallops, 190. Scaly ant-eater, 323. Scansores, 299, 315. Scaphandridae, 176. Scarlet tanager, 293. Scavengers, Diptera, 72; Lamelli- corns, 50. Schizopod larva, 116. Schizoneura, 14. Scolopendra, 75, 76, 78. INDEX 409 Scolopendrella, 78. Scolopendridae, 78. Scolytidae, 53, 61. Screech owl, 298, 299. Sculpin, 236, 252. Scutigera, 75, 78. Scutigeridae, 78. Scyphozoa, 214, 220. Sea-cows, 324. Sea-crayfish, 113. Sea-cucumbers, 204. Sea-lilies, 203. Sea-lions, 329. Sea-mats, 218. Sea-mouse, 148. Sea-spiders, 107. Sea-squirts, 218. Sea-urchins, 204 ; food and habitat of, 199-200. Sea-walnuts, 219. Seal, 328, 329. Searcher, 46. Sedentary polychaeta, 148. Selachians, 246. Selachii, 252. Semelidse, 189. Serpent stars, 203; description and habitat of, 199. Serpula, 151, 159; tube, 151. Serpulidae, 159. Sertularia, 210. Sexton beetles, 48. Sexual dimorphism of spiders, 92. Shad, 253; range, 243-244. Sharks, 252. Sharp-shinned hawk, 298. Sheep, 326. Sheep-tick, 70. Sheep scab, 94. Shipworms, 188. Short-horned diptera, 64. Short-horned grasshoppers, 51. Short-winged beetles, 47. Shrews, food of, 327. Shrike, 289. Shrimps, 104, 124; value of catch, 111. Sididae, 131. Silk-worms, 42. Silpha, 48. Silphidse, 48, 60. Silversides, 236, 252. Simia, 330. Simuliidae, 67. Simulium, 67. Siphonophora, 212-213, 220. Siphonata, 178. Siren, 255, 256. Sirenia, 331. Sirenidfe, 255, 266. Sitta, 287. Sittidae, 316. Skunks, 328. Sloths, 323; two-toed, 324. Slugs, 132, 160, 162 ; apparent absence of shell in, 162; economics of, 162; food of, 161-162; habitat of, 161; species of, 162. Smelt, 230, 253 ; artificial propagation of, 231 ; economic importance of, 230; habitat of, 230; range of Atlantic form of, 230-231; value of Atlantic fishery, 231. Snapping beetles, 51. Snapping turtles, 275. Snipes, habitat of, 305. Snout beetles, 61. Snow-bird, 285. Snowy owl, 299. Social bees, 31. Social life of ants, 36. Soft-shelled clams, 189. Solaster, 197-198. Solemyidae, 189. Solenidae, 182, 188. Song-sparrow, 285. Song-thrush, 285. Sow-bug, 112. Spanish fly, 58. Sparrow-hawk, 299. Speckled tortoise, 276. Spelerpes, color of, 259; development of, 261-262 ; habitat of, 260. Sphex, 82. Sphingidae, 22, 41. Sphinx moth, 23. Spiders, 80, 92 ; ballooning habits of, 83-84; classification of, 85; food of, 410 ZOOLOGY 82; poisonous, 91-92 : sexual di- morphism of, 92 ; spinning habits of, 83; wandering, 8K. Spider-crabs, 107, 123. Spider webs, economic importance of, 90. Spinning habits, in spiders, 83. Spiny ant-eater, 322. Spiny lobster, 101. Spirulidaj, 174. Spizella, 285. Sponges, 205. Spontaneous generation theory, 223. Spoonbill, habitat of, 247. Spore of Infusoria, 223. Sporozoa, 227, 229. Spotted sandpiper, 306. Spreading adder, 276. Spring azures, 18, 22. Square crabs, 123. Squash bug, 13. Squids, 171. Squilla, 111. Squirrel, 320. Stable-fly, 61. Stag-beetles, 49, 58. Staphylinidse, 47, 58. Starfish, 192,203; abnormalities of , 196; development of, 193-194; distribution and habitat of, 192; economic im- portance of, 193 ; food of, 193 ; larval stages of, 195; metamorphosis of, 195 ; systematic position of, 192. Stentor, 229 ; habitat of, 224-225. Sterna, 307. Sticklebacks, 238, 252. Stomatopoda, 111, 122. Storks, 305. Strongylocentrotus, 199. Sturgeons, 247 ; economic importance, habitat, food of, 247. Suckers, 241, 253. Suctoria, 225, 229. Sunfish, 235, 252. Swallows, 292. Swarm of bees, 32. Swifts, 301, 302. Sycon, 206. Syllidee, 159. Sylvicolidse, 317. Sylviidse, 285, 315, 316. Synapta, 202, 203. Synotus, 329. Syrphidse, 66, 73. Syrpus, 64. Tabanidse, 65. Tabanus,65, 66. Tsenia, 157. Talorchestia, 112. Tanagers, 292. Tanagridse, 292. Tapeworm, 156 ; human, 157. Tapirs, 327. Tarantula, 92. Teeth of fossil birds, 314. Teleostei, 252. Tellinidse, 190. Tenebrio, 52. Tenebrionidse, 52, 61. Tent caterpillars, 26; egg masses of, 26 ; nests of, 27. Terebellidaj, 159. Teredidse, 181, 188. Teredo, 181. Termes, 11. Termites, 11. .. Terns, 306, 307. Terrapene, 275. Territelarise, 85, 95. Testudinidse, 275. Texas fever in cattle, 228. Thalassinidae, 105, 124. Theclas, 22. Theridium, 80, 82; food of, 82. Thomisus, 90. Thrushes, 385. Tineidse, 29, 42. Tigers, 328. Tiger-beetles, 45. Tiger-moths, 24, 41. Tipulidae, 68-69. Titmice, 286. Toadtishes, 252 ; habitat of, 236. Tornatinidae, 176. Tortricidse, 29, 42. Toucans, 299. INDEX 411 Trachea of fly, 63. Tracheata, 387. Trachina, 152, 153. Trachomedusae, 221. Trap-door spiders, 80. Tree-hoppers, 14. Trematoda, 385. Trepangs, economic importance of, 202. Tree-sparrow, 285. Tree-toad, 265. Triangular crabs, 123. Triforidae, 177. Trilobites, 130. Trionychidae, 274. Trionyx, 275. Trochidae, 175. Trochilus, 302. Troglodytidae, 287, 316. Troglodytes, 288. T routs, 233, 253. True bugs, 12. True wasps 83. Tsetse-fly, 64. Tube-forming worms, 102. Tube-weavers, 88, 96. Tubifex, 136, 144. Tubificidae, 144. Tubitelariae, 88, 96. . Tubularia, 208. Tubularian hydroid, 210. Tubularidaj, 208, 221. Tumble-bugs, 50, 57. Tunicata, 218, 251. Tunnel-weavers, 85, 95. Turbellaria, 385. Turdidge, 285, 315, 316. Turdus, 286. Turkey-buzzard, 299. Turkeys, 304; wild, 305. Turtles, 273; range of , 274. Tussock moth, 28". Twin-spotted sphinx, 23. Tyrannidae, 295, 315. Tyranuus, 296. Unau, 324. Ungulata, 325, 331; even-toed, 326; odd-toed, 327. Unio, 178, 191. Unionidas, 179, 180, 191. Urodela, 255, 266 ; development of, 261. Urosalpiux, 169, 175. Varanidae, 269. Variations in Helix, 1(55. Veneridae, 180, 183, 190. Venus, 183. Vermetidae, 174. Vertebrates, ancestry of, 248. Vespa, 34, 35. Vesper sparrow, 285. Vesperidae, 43. Vespidae, 33. Vireo, 288, 290. Vireonidae, 288, 316, 317. Volvox, 226, 227. Von Baer's law, 336. Vorticella, 225, 229. Vultures, 298, 299. W Walking-sticks, 7, 15. Wall-eyed pike, 235. Walruses, 329. Wandering spiders, 88. Warblers, 285. Wasps, 30, 33, 43; social, 33. Water-dog, 257.. Water moccasin, 279. Water scavengers, 60. Water snakes. 271. Water strider, 12. Weasels, 328. Weevils, 57. Whales, 324; feeding habits of. 325. Whippoorwill, 303. Whirligig, 60. White ants, 11. White-breasted nuthatch, 287. Whitefishes, 234, 253. White-lined horse-fly, 6(5. WThite-throated sparrow, 285. Wingless birds, 307. Wingless cockroach, 8. AVood-borers, 41. 412 ZOOLOGY Woodchuck, 320. Wood frog, 266. Woodpeckers, 301. Wood-tortoise, 276. Wood-thrush, 286. Wood-warblers, 287. Worms, tube-forming, 102. Wrens, 287. X Xylotropidae, 23, 41. Yellow bird, 285. Yellow warbler, 288. Yoldia, 187, 188. Zebra, 327. Zebra swallow-tail, 18. Zygaenidae, 41. Zygodactyla, 212. A TEXT-BOOK OF ZOOLOGY BY T. JEFFERY PARKER, D.Sc., F.R.S. Professor of Biology in University of Otago, Dunedin, N.Z. WILLIAM A. HASWELL, M.A., D.Sc., F.R.S. Professor of Biology in the University of Sydney, N.S.W. In two volumes, containing many illustrations Cloth. 8vo. 2 vols. $9.OO, net " The book deserves a warm welcome, and . . . will be found an invaluable aid not only to students of zoology, but also to a large num- ber of those whose main interest lies in other branches of scientific study. Written with a clearness, accuracy, and method of a practised teacher, it is admirably illustrated with a profusion of figures — there are nearly twelve hundred in all — of the highest excellence." — Science. "This work, the significance and usefulness of which must be un- qualifiedly conceded, represents an enormous amount of labor upon the part of two experienced teachers. Nor would we underrate the admirable mechanical features of the work and the educational por- tent of the issue of so large and costly a text-book upon a single branch of natural history. The intent and method of the authors are clearly set forth in the preface. After a general introduction and a section upon ' General Structure and Physiology,' there are presented in turn the twelve phylums recognized, viz. : Protozoa, Porifera, Coelen- terata, Platyhelminths, Nemathelminths, Trochelminths, Molluscoida, Echinodermata, Annulata, Arthropoda, Mollusca, and (occupying the whole of the second volume) Chordata, corresponding nearly with Vertebrates. The discussion of each class is based upon a more or less detailed account of the anatomy and development of one or more forms, fairly representative and commonly available. The second volume also contains a discussion of the mutual relationships of the Chordata and of the twelve phyla. The last seventy pages are devoted to Geographic Distribution, the Philosophy and History of Zoology, and Modern Literature; seven of the sixty writers recommended being American." — The Nation. THE MACMILLAN COMPANY NEW YORK CHICAGO BOSTON SAN FRANCISCO EXPERIMENTAL MORPHOLOGY BY CHARLES BENEDICT DAVENPORT, Ph.D. Instructor in Zoology in Harvard University PART I. Effects of Chemical and Physical Agents upon the Protoplasm Cloth. 8vo. $2.6O, net PART ii. --: Effects of Chemical and Physical Agents upon Growth Cloth. 8vo. $2.OO, net "The material which is discussed has been well digested and is well arranged, and the style is on the whole clear and concise. The book is a readable one, and the descriptions and criticisms of the methods employed in experimentation, and the bibliographical lists at the conclusion of each chapter, con- tribute materially to the value the book possesses for both the morphologist and the physiologist." — Science. " In this second instalment of his valuable treatise, Dr. Davenport considers the effects of chemical and physical agents on growth. Plants lend themselves so readily to observations respecting growth that they have received from Dr. Davenport a degree of attention in this work which compels the student of plant physiology to accept his aid. On the whole, the edi- torial work has been wonderfully well done, and the errors are so few that they need not be mentioned here ; they do not appear likely to mislead seriously any students who make use of the vast amount of material which has been gathered patiently, and for the most part has been well arranged." — American Journal of Science. THE MACMILLAN COMPANY NEW YORK CHICAGO BOSTON SAN FRANCISCO UNIVERSITY OF CALIFORNIA LIBRARY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW 5161 SUB 29 1918 FEB 3 1921 fcl NOV 14 IS27 OEC 2 1 ,353 NQV251968 8 i z * I 01 • 1 0 > z 3 Om- 6,'J 7 73? BIOLOGY tit