M- .^' tt '^' DEN' Z^> I UNIVEKSITY OF COUO««w i^O T.\ ^^' MUSEUM Ml X'\ BOULDER. COLORAOa AMEEICAN SPIDEES AND THEIR SPINNINGAVORK. -®- A NATURAL HISTORY OF THE ORBWEAVING SPlDERtS OF THE UNITED STATES WITH SPECIAL REGARD TO THEIR INDUSTRY AND HABITS. -®- 15 Y HENEY C. McCOOK, D. D., Vice-President of the Academy of Natural Sciences of Philadelphia; Vice-President of the American Entomological Society ; Author of " The Aorici'ltural Ants of Texas," " The Honey and Occident Ants," ETC., etc. VOL. 1 PUBLISHED BY THE AUTHOR, Academy of Natural Sciences ok Piiiladklimiia. A. D. 1889. AUTHOE^S EDITION. This Edition is limited to Two Hundred and Fifty copies, of which this set is SuBSCRIPTIOi Author's Signaturk,..* THE PUUH.S OK ALLKN, LANK 4 SCOTT, rilll.ADI'.l.l-illA. THESE STUDIES IN NATURAL HISTORY ARE DEDICATED TO THE VENERATED MEMORY OF MY FATHER, JOHN M( COOK, M. D, A LOVER OF NATURE, A FRIEND OF SCIENCE, A GOOD PHYSICIAN, A SERVANT OF HIS FELLOW MEN WHOSE FAITH IN THE UNSEEN NEVER FALTERED. r» >i r tr PREFACE. The studies whose results are here given have been prosecuted throughout the last sixteen years. I have largely limited my investiga- tions to the habits and industry of spiders, as the matters which seemed most important at this stage of scientific knowledge. None but the field naturalist can fully know and appreciate the diffi- culties of my task. To these ordinary obstacles have been added special hindrances of my own. The cabinet or laboratory student, with A Field Yiis pinned and alcoliolic specimens, is largely independent of • ^.. Y).f^ outward conditions; but he who studies nature as a living thing culties i'^ ^^^^ servant of seasons, hours, moods. He must live amidst the life which he would see, and seize the opportunities as they come, or lose his venture for that season or year, or perhaps wholly. The duties of my calling in a large city have held me rigorously away from the open country except during two months of the year. Summer vaca- tions, and such leisure hours as a most busy life would allow, have been given to the pleasant task of following my little friends of the aranead world into their retreats, and watching at the doors of their fragile domi- ciles for such secrets of their career as they might happen to uncover. Occasional excursions at other times were unavoidably brief, and often broken off at the point of promised discoveries. I have, in part, indeed, overcome this obstacle by transporting and colonizing specimens, and by directing the observations of others. But, at the best, artificial conditions fall short of Nature's fullness, and no faithfulness of assistants can quite equal personal investigations. Then, again, the natural disposition of the spider is a great hindrance to the prosecution of field studies. It is a solitary and secretive animal, and the most ingenious device for winning its confidence is as , i^pt to drive it into hiding as to persuade it to revelations. In c, ,., , this respect there is a great difference between these solitary Nature, creatures and those soeiable and demonstrative insects, the ants, whose life history I have heretofore been permitted to give to the scientific world. The success which was readily obtained by spending a few weeks or months encamped among formicaries of emmets, contin- ually eluded me when trying like methods with araneads. (5) PREFACE. To be sure, in some respects the Orbweavers and Lineweavers are more approachable than other tribes of spiders; for, as they are sedentary crea- tures, and are found continuously upon their webs, one often has the oppor- tunity to observe them with comparative freedom and comfort. But this is only true of the commoner species, and of that part of their life which concerns the structure of snares and trapping of food. In other, and even more interesting fields, these sedentary spiders, like all the wandering groups, persistently conceal their manners. When it is considered that most of the facts presented in my books consecutively, as a connected history, have been collected under such diffi- culties, and at widely separated periods and places, it is not strange that some gaps in the life record may be found. But, if in some parts the connecting links are lacking, and the story is incomplete, it is no more than ordinarily befalls other naturalists when investigating the habits of other animals. While, therefore, no one can regret more than I the Idanks which here and there occur in the pages of that wonderful his- tory of industrial life and art which I have attempted to unfold, I ven- ture to urge the above reasons for indulgence towards any failures which may appear. The general plan of my work, as it will be given to the public, may briefly be stated as follows : The first volume is chiefly taken up with de- scriptions of those parts of aranead spinningwork which are gen- General ei-ally known as the web or snare, and the nest or den. The the Work ^^"^^^^ concerns the nurture of the spider, as the snare is its manufactured tool for capturing insects. The latter concerns the protection of the animal from changes of weather and assaults of enemies. In my studies of the snares of Orbweavers, I have tried to obtain the full- est possible details of the spinning methods of every species; to mark the striking differences which exist among the various groups; and to associate these, as far as my knowledge would permit, with the general habits of Plan of ^^^^ various families. Furthermore, I have brought to bear upon Volume I. ^^^^^^> "^ ^ comparative way, the spinningwork and habits of other tribes, so that the reader may be able to trace resemblances aufl differences, and to perceive what relations, if any, exist between the general life habits of all spiders. The consideration of these topics has necessarily suggested the degree of intelligence and the variety and adaptation of methods shown by spi- ders in their ordinary and special behavior. Thus have come into view the profound and interesting problems relating to animal mentalism. Fmally, I have endeavored, in the closing chapters, to present a bird's eye view of the entire field of industrial life treated of in the volume, with special bearing upon a common origin, whether from the one stand- point of a single originating Mind, or from the other standpoint of a genetic evolution from common ancestral actions and tendencies. PREFACE. In the second volume I shall take up and treat in the same way the habits and industry associated with mating and maternal instincts, the life of the young, the distribution of species, and other general Plan of habits indicated in the appended table of contents. The third II a din ^'^^^^^^ ^^ ^^® series will be a systematic presentation of the Orbweavers of the United States, and this I hope to make toler- ably complete. The descriptions will be accompanied by a number of plates drawn in the best style of lithographic art, and j^ainted by hand in the colors of nature. The above plan is the result of an entire change in my original pur- pose, which was to write a natural history of all American spiders, following consecutively and separately the several tribes, beginning with the Orb- weavers. A vast amount of material has been gathered with p. this purpose in view, but I have found that the work thus marked out is so great that I doubt my ability to accomplish it all. For, even should my life be sufficiently lengthened to overtake the entire field mapped out, the expense of the undertaking appears to be an impassable barrier. I have, therefore, concluded to introduce, in the com- l)arative way referred to, such notes of tribes, other than Orbweavers, as seemed most desirable and important for solution of the various problems which have arisen as my studies progressed. Thus, while the Orbweavers are treated fully, the natural history of all other tribes of our spider fauna comes well into view. Although I confess some regret at the abandonment of the original plan, I am confident that most naturalists will agree with me that tlie present treatment adds to the value of the volumes now pub- lished, and is, perhaps, after all the best that could have been adopted. There is another point at which this work departs from my original plan. As my observations have especially traversed the spinning habits of spiders, it seemed important to make a careful study of the spin- Study oi j^jjjg organs, not only of Orbweavers, but of all other spider Ore-ans bribes. It was thought that such a comparative study would not only give valuable hints in the systematic determination of the animals, but would have an especial bearing upon the variations in spin- ning habit. It was inferred that there must be some connection between special function and the organs thereof. In this line work was begun and prosecuted far enough to see how promising and interesting is the field. But a severe attack of sickness, whose consequences were felt for several years, compelled an entire cessation of work with the dissecting knife and microscope. I was, therefore, reluctantly compelled to omit from the oi)en- ing chapters much material which I had hoped to present, and to limit my illustrations to the few which are really necessary to give the reader a correct idea of the structure of the s})inning organs and the manner in which the si)inning material of spiders is formed. Even these illustrations I have borrowed in part from others. I venture to express the hope that 8 PREFACE. some one who can thoroughly prosecute this line of studies will be led to take it up and give the results to the scientific world. I have made a point of illustrating all descriptions with drawings whenever the proper material was in hand. During my studies of ara- nead spinningwork, I have made thousands of original sketches Full Illus- .^ ^^^^g books, from which I have selected those that seemed best suited to make clear the points treated of. Judging by my own experience, even an outline drawing is better to communicate certain facts than pages of verbal explanation. Acting upon this belief, I have preferred to risk excessive illustration rather than fall upon obscure descrip- tion. Indeed, I cherish the hope that the contents of some of the follow- ing chapters might be fairly understood by a simple examination of the cuts with their explanatory legends. I have not been unmindful of the artistic sense of my readers, which, I trust, has been measurably satisfied ; but I take it for granted that those who honor me by looking at my work will understand that the chief object of the engravings is to make plain what I have to say. In other words, the figures are for illustration and not for embellishment. Many of the cuts have been redrawn by competent artists, but a large number remain as figured by myself on block or paper. Among those who have assisted in making the drawings are the well known artists and arachnologists, Mr. J. H. Emerton, of Boston, and Dr. George Marx, of Washington ; also, Messrs. Edwin Sheppard and Frank Stout, of the Acad- emy of Natural Sciences of Philadelphia; and the Misses Bonsall, of this city. It may not be out of place to allude to the fact that, in order to give my investigations to the public in any form that would satisfy me, I have been compelled to undertake the entire burden and expense of A ^h*^^ publication. Few things could be more inconvenient and dis- Publisher ^^^^^f^*! ihein the business details thus imposed ; but I have ac- cepted them as a part of the sacrifice required of one who, as a prophet of the mysteries of Nature, feels called to declare, at whatever cost, the truths known to him. Those who have undergone a like experience need not be told that the amount of loss to fall ui)on an author will bo largely determined by the interest which friends and associates take in procuring for his book a place on the shelves of scientific societies and loading libraries. I have received many favors and much generous help in procuring in- formation and specimens from various naturalists and friends, for which Thanks. ^ express my thanks. I have tried to give full credit to all in the appropriate place in text or foot note, but will make de- served i)ersoiial acknowledgments in a succeeding volume. ,, ,, H. C. McC. Piiii.ADKi.i'iijA, November 1st, 1S8!». TABLE OF CONTENTS OF VOLUME T. PART L— STRUCTURE AND SPINNING ORGANS. CHAPTER I. GENERAL CLASSIFICATION AND STRUCTUKE. PAGES The Origin of the Name Spider — Principal (n-oupp, Sedentary and Wandering— Tribal Divisions — Blackwall's Classification — Thorell and Bertkau — Highest Fornis^Sui)eri- ority of Lycosids — Orbweavers and Lineweavers — Anatomy of a Spider — Caput — Eyes — Mandibles -Sternum — Labium — ^Maxill;^ and Palps — Legs and Claws — The Abdomen — Pulmonary Sac -The Epigynum and ^fale Organs — Hints to Collector — A Spidery— How to Observe Spinningwork and Habits —I'reserving Specimens . . 15-33 CHAPTER II. THE SPINNING ORGANS. External Spinning Organs — The Spinnerets or Spinning Fingers — The Posterior Spin- nerets — ^liddle Spinnerets — Anterior Spinnerets — Bucholz and Landois' Studies — Studies of Meckel — Spinning Spools — Internal Spinning Organs — Silk (ilands^Liquid Silk — Pyriform (ilands and Ducts — Cylindrical (ilands — Treefonn (ilands — Sjjinning Spools of the Pyriform (ilands — Spigot Spools — Spools of ]\Iiddie and Anterior Spin- nerets — Generic Differences in Spinning Spools — The iMuscular System fur Kxpelling Silk ' 34-51 PART II.— GENERAL CHARACTERISTICS, CONSTRUCTION, AND ARMATURE OF WEBS. CHAPTER III. GENERAL CHARACTEKISTICS OF OlUnVEA VERS' SNARES. Popular Errors — An Orbweb Defined — (ireat (iroups of Orliwcbs— Tarts of tlie Orb — Forms of the Hub— The Free Zone— Notched Zoiu' 52-5!i CHAPTER IV. CONSTRUCTION OF AN ORBWEH. Laying Out tlie Frame — Dragline — Tlic I'rinu' Foundation — Foundations l)y Air Currents — Bridge Lines— Webs Between Trees— Webs on Water Plants — Cobweb Bridges — Trial Air Lines — Swinging Inspection Baskets— Jonatlian Edwards as an Arachnologist — Double Foundation Lines — I'laciiig in Radii — Alternate Apposition of Uadii — Form- ing the Notified Zone (50-78 (9) 10 TABLE OF CONTENTS. CHAPTER V. ARMATURE OF ORBWEBS : VISCID SPIRALS. PAGES Spiral Scaffolding— t'orncr Loops— Spinning Viscid Spirals— Cutting Away the Scaffold- Size of Beads— Elasticity of Spiral Lino— Formation of Beads— Beads Dissolved by Rains— Tortion of Spirals by Rain— Xuiuber and Adhesiveness of Beads— Medicinal Properties 79-95 PART III.— CHARACTERISTIC FORMS AND VARIATIONS OF SNARES. CHAPTER VI. ARGIOPE AND HER RIBBONED ORB. Full Orbs— Argiope cophinaria, the Basket Argiope— Distril^ution and Habitat — The Zig- zag Ribbon— The Central Shield— How the Shield is Spun — Spinning the Zigzag Ribbon— A Spider Diary — Swathing Insects — The Notched Zone— Fenders or Pro- tective AVings— AVeb of the Male Argiope— Size and Details of Orbs — Argiope argyraspis, the Banded Argiope— An African Argiope — The Silvered Argiope, A. argenteola 96-109 CHAPTER VII. EPEIRA AND THE ROUND VERTICAL WEB MAKERS. Familiar Orbwebs — Epeira Strix, the Furrow Spider — Spider Stowaways — The Head Downward Position — How the Feet Connnand the Snare — "Under Her Thumb" — Natural Sites of Snares— Epeira domiciliorum, or the Domicile Spider — The Insular Spider, Epeira insularis — The Shamrock Spider, Epeira trifolium — Tents in Hedge- rows — Epeira vertebrata — A California Colonist — Epeira trivittata — Gasteracantha — Tufted Webs — Orl^s with Open Hubs — Acrosoma — The IMitred Spider — Epeira cau- data, the Tailed Spider— Meta— A Cave Dweller 110-129 CHAPTER VIII. COMPOSITE SNARES AND SECTORAL ORBS. The Labyrinth Spider— How tlie Maze is Made— Uses of tiie Labyrinth— The Orb— The Trapline and Hub — Favorite Sites — Epeira triaranea — Open Sector and Free Radius — Orientation of Trai)linc— S|)irals Spun in Loops — Tiie Spinningwork of Three Tribes in One Welj -Epeira tliaddeus—Zilla and Her Snare— A Scotrli Colony — AVilder's Nephila— Nephila's Snare 130-149 CHAPTER IX. HORIZONTAL SNARES AND DOMED ORBS. The Orchard Spider— Variations in the Orb Plane— Protective Apron— The Iluiulihack Spi.lcr, KiK'ira gibherosa— Iluncliback's I lammock— Tetragnatha extensa— Cosmo- poHtan I)iHtril)iition— Tlie Stilt Spider, Tetragnatha grallator— Snares Over tlie Water— Tetragnatha as a Sailor— InMuence of Distribution and l^nvironment- Climate as Influencing Distrihiilioii -Domed ( )rl)s— Tlic I'.asilica Spider— Basilica Spider's Domed Orl)— Basilica aniders— A Spider Captures a Fish— A Snake En- snared by a Spider — Medicinal Spider's Snare — Theridium Captures a Mouse— Mr. Hopper's Testimony — Hon. Proctor Knott's Testimony — The Conclusion — The Inci- dent Proved— The Arancad Heroine 229 246 12 TABLE OF CONTENTS. PART VL— PROVISION FOR NURTURE AND DEFENSE. CHAPTER XV. PROCURING FOOD AND FEEDING. PAGE8 Food taking Tools— Handling the Snare— Accuracy of Perception— Treatment of Insects- Swathing the Prey— The Banquet Room— Deporting SAvathed Insects— Trussing Cap- tives— Acrosoma Trapping Flies -Order and Subordination of Instincts— Flies Ban- queting with a Spider— Location Controls Food— Prolonged Abstinence— Comparative Feeding Habits— How the Tarantula Feeds— Need of Water— Drinking Habits- Does the Spider Eat Its Web?— Wear and Tear of Snares— Mending the Web— En- tangling Insects— The Spider as a Philanthropist — Man as an Ingrate 247-267 CHAPTER XVI. EFFECTS AND USES OF POISON. The Fangs and Poison Bag — Blackwall's Experiments— Effect of Epeira's Bite— The Inoculation Test— General Harmlessness of Spiders— The Other Side— The Venomous Spider of Xew Zealand— Latrodectus mactans— The Popular "Black Spider "—In- definite Testimony — Phidippus morsitans —Effect of Spider Venom on Insects — Poison as a Reserve Weapon— Popular Notions- Medical Imaginings— Queer Reme- dies—Useless Fears 268-283 PART VII.— NESTING HABITS, PROTECTIVE ARCHITECTURE, AND DEVELOPMENT. CHAPTER XVII. NESTING HABITS AND PROTECTIVE ARCHITECTURE OF ORBWEAVERS. Varieties of Spinningwork — The Nests of Epeira insularis — Leaf I'ollcd Habitations — Woven Tents — Shelter Tents — Spider Seamstresses— Variations in Individual Habit — SjK'cial Adaptations— The Shamrock Spider's Nest— Epeira domiciliorum and tria- ranea — The Angulata Croup — How the Spider ]Makes a Nest — Sewing Leaves To- gether—Spider Upholstery —Nest of the Voung — The Nest of Epeira thaddeus— The Domed Tent of Triaranea — Labyrinthea's Nest — The Leafy Canopy oC Labyrinthea — Origin f)f the Nest making Habit — Intelligent Selection — Design Showed in Sewing — Nesting Industry Protective- N'arious iMjrnis (jf Tents Summarized 28-i-;il2 CHAPTER XVIII. NEST MAKING : ITS ORIGIN AND USE : DEVELOPMENT IN VARIOUS TRIBES. Comparative Studies— Nests of Tubeweavers — Saltigrades— Linewt-avcrs — Theridiiun rii)ar- ium, the Prince of Spider Architects— Mode of Building— Use of Artificial INLaterial - Nesting Snares of Linypliia- A Tent Among the ^^lorning (dories -Territclarian Tubes- Atypus and Cyrtauclienius— Nesting Habit of Citigrades— Of l^aterigrades — One Common and Typical Form of Nest— The Modes of Making Nests— INIethod of Atypufi-Of tlie Mygalidte- Of tlie Water Spider— Of Speckled Agalena— Unity of Method in All Tril)cs — Nest Parasitism -S(|uatter Sovereignty — Com]>arison with Otlier Orders— Tube making Larvic- Nests of tlie Caddis Fly Larva- Leaf thatclied Nest of the Bag Worm— Nest »i' a Tlicridioid Spider— The Leaf roller Tortricid Moth— Shamrock Spider's Nest in tiie Ferns— The Shell of I )ifHugia— Catholic Ke- fiemhkni'c in External Arcljitecture- Creation's Harmoiiv 313-33.5 TABLE OF CONTENTS. 13 CHAPTER XIX. GENESIS OF SNARES. PAGES Spinningwork Relations — A Hypothetii-al Standpoint — (Tenesis of a Trapline— A Simple Trail — Trail Telegraph— Foot Lines Conunaiiding Snare — Acrosoma at Her Huh — Utilizing Web Fragments — Stellate Spider Trajiping witli a Fragment — ^lultiplex Trajjlines— Hyptiotes" Trapline — Kay Sjjider's Trapline — Tlie Original Thread — Drag- line — Trestlework of Theridium — Theridium's Parental Snare — Beautiful Snares of Linyphia — Snare Among the Morning (ilories — From Sheet to Dome— From Dome to Tube — Liny])hia eostata's Snare — Influence of Maternity — Coeooning Xest of Dolo- medes — CV)(")perative lIousekee])ing — Origin of Orl)\vel)S — Dietyna's Orl) like Snare — Orhweavers' Curled Spirals — The Ray Spider's Link— \'iscid Lines of Dictyna and Amaurobius — Are Theridium's Tlireads ^'is(•id?— Another Starting Point — From Tu])e\veaver to LineAveaver — Agalena and Theridium P>peira and Tlieridium — Sec- toral and Horizontal Orbs— Unity of Industrial Habit 88()-35(> CO^TEISTTS OF VOLUME IL Chapter I. Wooing and Mating of Orbweavers. II. Courtship and Pairing of the Tribes : Love Dances of Saltigrades. III. Maternal Industry : Cocoons of Orbweavers. IV. Cocooning Habits of 8i)iders : Comparative Industries. V. Maternal Instincts : Motherhood. VI. Cocoon Life and Babyhood. VII. Aeronautic or Ballooning Habit: Distribution of Species. VIII. Senses of Spiders, and their Relations to Habit. IX. Color and Color Sense : their Relations to Structure and Habit. X. Toilet, Moulting, and General Habits. XI. The Orbweavers' Enemies. XII. Mimicry. XIII. Deatli and its Disguises. XIV. Fossil Spiders : Habits and Habitat of Ancestral Araneads. CHAPTER I. GENERAL CLASSIFICATION AND STRUCTURE. The order Aranese has given the name of the true spiders, which it embraces, to the class of invertebrates to which it belongs, Arachnida. This - . . name, again, is due to that special function by which the spider th N ^^ ^^^^ ^^^^ ^^^^ been popularly known. According to the Greek myth, Arachne was transformed into a spider by Pallas Minerva because she had boasted her superiority over that goddess in the use of the distaff. Hence the Greek name for spider {dpdyyrj), arachne. The Eng- lish name is doubtless derived from the same function which led the un- happy Arachne upon her doom.^ Spider is a corruption of "spinder," the spinning one. The word survives in a different form in the term " spinster," by which the virgin mistress of the distaff was commonly known in the days of our grand- sires. There is therefore a popular and phil- ological as well as natural fitness in the gen- eral classification of the order Aranese which we adopt after Thorell,^ wlio in turn has substantially followed the arrangement of La- treille.^ This classification is based upon the web making characteristics of the various groups and is as follows : The order may be divided into two principal groups, the Sedentary spiders and the AVan- dering spiders.^ The former group includes those whose habit it is to remain, for the most part, upon or within their webs and take their prey by means of snares. The second group includes those which stalk or pursue their prey ^ See Ovid's Metamorphoses, Chap. vi. The story is told in the first 150 Hnes. 2 On European Spidoi-s, by T. Thorell. Nova Acta Reg. Soe. Scientariuni UpsaUensis. Upsala, 18G9. ^ Latreille : In Cuvicr's "Le Resrne Animal," edition 1S17, ParlH. Pedentaires (Sedentary), page 79 ; Vagabondes (Wandering), page 95 ; Territeles, page 79 ; TubiteK-.^, page 81 ; Inequi- teles (Retitelariae), page 84 ; Orbiteles, page 8G ; Laterigrades, page 91 ; Citigrades, page 95 ; Saltigrades, page 98. (15) General Classifi- cation. Fig. 1. An Orbweaver, Epeira gemma. 10 AMERICAN SPIDERS AND THEIR SPINNINGWORK. Seden- tary Group iitield, upon the ground, water, or trees, and as a rule have no fixed domi- cile, except at the brooding time and during winter. These principal groups are subdivided into seven secondary groups, sections or suborders. ^ The four tribes comprising the Sedentary spiders are named strictly from the -chief characteristics of their spinningwork, viz. : the Orbi- telariffi, from their orb shaped web; the Retitelarise, from their net like web or snare of crossed lines ; the Tubitelarise, from the tubular web which they spin, and from the opening of which, in some species, a close textured snare spreads out in all directions; the Territelarise, from the silken cylinder with which the typical species line their burrows in the ground. The Wandering spiders include three tribes, which are conspicuous by their ordinary independence of snares for the capture of prey, and have been named from certain pe- culiarities of motion. The Wander- ^^terigrad^ have legs so mg Group . ° ° niserted as to permit a motion sidewise, as well as forward or backward. For this reason La- treille called them also Grab spiders. The Citigradte include those species that keep chiefly to the land and Avater, upon which they run witli great rapidity. The Saltigradse, or vaulting spiders, are named from their hopping movement in ordi- nary progress. The individuals of these three tribes are almost equal- ly entitled to be called citigrades, for they all move swiftly, but the Citigrades technically so termed are Fig. 2. Territelariae : Eurypelma Steindachnerii Ausserer. habitually running SpiderS, keeping (Dr. Marx, del.) Natural size. cloSCly UpOll the grOUud, whilc the Latcrigrades and Saltigrades are arboreal, habitually dwelling upon plants and vertical surfaces. The three are also quite distinct in their structure, and the systematic position of any one, as far as above indicated, can com- monly be told by a ghince at the form. ' Thorell uhch thi' term " sulmrdcrs " in his European Si)i(U'rs for llu'sr iniiicipal .i:riiui)s, but adopts the term "Hirtions" in iiis "Descriptions of the Aranete of Colorado" (Bulletin U. S. (Jeologieal Survey, \n]. III., No. 2, page 477, note), and still later the name tribe (tribus). GENERAL CLASSIFIC^ATIOX AND STRUCTl JIE. Tlio following tabular exhibit is given of this classification, or group- ing, if that word seems to any one more suitable: — Class Arachnida. Order Arane;k. I. l^irst Division. — Sedeiilarv Spiders. Tribe 1. Orbitelarite,^ Orbweavers. " 2. Retitelarife,^ Lineweavers. 11. Second Uivision.- Tribc 5. Citigradie,^ Citigrades. Black- "wall's Classifi- cation. Tribe 3. Tubitelarite, Tubeweavers. " 4. Territelaritc, Tunnel weavers. Wandering Spiders. Tribe (3. Laterigradie, Laterigrades. Tribe 7. Saltigrada', Saltigrades. This arrangement is the best, perhaps, tliat can be adopted, and seems more natural and satisfactory than that wliicli commanded the ajiproval of such a distinguished arachnologist as Blackwall, and which is based upon the number of the eyes. Blackwall founded three tribes, within whicli all the species known to him are includ- ed. They are: (1) Octonoculina, eyes, eight ; (2) Senoculina, eyes, six ; (3) Binoculina, eyes, two. In tlie first tribe, Octonoculina, whieli is the most extensive of tlie three, he included all tlie genera having eiglit eyes, without regard to other characteristics or to the considerable dif- ferences in organization and economy. The second tril)e, Senoculina, as known to Black- wall included but ten or eleven genera, and embraced all tribes having six eyes, with the same disregard to other char- acteristics. The third tribe, Binoculina, contained the single genus Nops, instituted by Mr. W. S. McLeay for the reception of two remarkaljle species of extra European spiders.* The Latreillian classification, which Thorell ^ Araneie Orbitelariip: Perty, Delect. Aniin. .\rt. Bras., pajro 19:^. ^ From retus, a net. Tlio word "net" very well exjjresses the knotteil and iiu'slird char- acter of most si)iiiiuii<>:work of this ^roup. But since it is used popularly as a general tenn for the \ve1)s of all spiders, I have preferred "Lineweavers" to "Netweavers" as a dis- tinctive popular name of liiis tri])e. M'rof. Thorell assijrns the Laterij,'rades to the liftii tril)e, the C'itij^rades to the si.xth. I liave ventured to so far chanjje this arran<,'enient as to rever.se the positions of the Lateri- •rrades ami ('itimadcs. The ( 'itiixrailes a|i]iear to me to approach tlie Tunnehvea vers and TulH'weavers, Itoth in structure ami economy, more nearly than the l>ateriirrad«'S. So also the step from the ("iti<,'rades to the Laterigrades throu^^h the assa,Lre is certainly easit-r. ' lUackwall. Spiders of (ireat Hritain and Ireland," Preface, jia^'e <>. Fig. 3. Laterigrade Spider, Misume na rosea Keyserling. 18 AMERICAN SPIDERS AND THEIR SPINNINGWORK. has SO admirably expressed as above, will at least be preferred by those who set as much store upon the habits and functions of the creatures as upon their forms. The latter indeed will not be undervalued by a wise and careful student; but the systematists and anatomists will doubtless bear with those who would fain keep natural history from swinging too far away from the paths which earlier naturalists trod, and which so thoroughly traversed the life history of created things. A general classification based upon the spider's behavior, especially in relation to its chief function, has the advantage that it compels attention to the creature's habit without at all neglecting its structure. It The Clas- jg ^^^ claimed that this classification is without objections. There T o.-^ J are, indeed, some incongruities, more or less serious, which will Justified. ' ' . . appear hereafter. But until these interesting animals shall have received from naturalists that attention which their character and impor- tance in nature justify, and which will enable some future arachnologist to show us a better way, we shall, perhaps, be best repaid by accepting this general grouping of the great families of the spider fauna. At least it is that which best serves my own purposes in the special lines marked out for this treatise. Students w^ho are interested in a more thorough consideration of this point will find the objections to the above system well stated, and a classi- fication proposed based more upon anatomical structure, by Dr. Philip Bertkau, of Bonn.^ A very satisfactory answer to these objections has been [>u])lished by Prof. Tamarlan Thorell, M. D.,^ who adheres substan- tially to his former system but, confessing his indebtedness to Prof. Bert- kau for certain modifications, proposes a rearrangement which, he thinks, answers to our present knowledge of this order, as follows : — Ordo AraneyE. SUBORDO I. TeTRAPNEUMONES. Tribus I. Territelarias. SuBORDO II. DiPNEUMONES. Tribus II. Tubitelarite. Ecribellata). Cribellatse. Tribus III. Retitelaria3. Tribus IV. Orbitelarise. Cribellatffi. Ecribellatte. Tribus V. Laterigrada3. Tribus VI. Citigrada). Tribus VII. Saltigradae. Tlie scheme embraces European families for the most part, but includes a few exotic ones. 'See especially his "Versuch einer naturlichen Anordnung tier Spinnen," in Archiv fiir NuturgeHclii(-hte, xliv., i., i)ago .351, sq., 1878; and his treatise "Ueber das Cribellum iind Cala- niiHtruiii. Ein Beitrag zur Ilistiologio, Hi()lo<-ie, nnd Systcmntik (l(>r Spinnen," iltid., xlviii., i. page 81(1, et sofi., 1882. '^Annals an lOpciroiil inaU's witli strmiLi'ly iirdjcctiiiL: Cnrc- licad, anil in llic L^cniis TapiiL-pa, among tiic Kef itclaria'. Fig. 7. Liuevveaving Spider, Therid- iuni tepidariorum. (Marx, del.) GENERAL CLASSIFICATION AND STllUCTUKE. 21 Thus Fig. 8 represents the eyes of an Epeira, and Fig. 9 the eyes of the Retitelarian genus Theridium. Dr. Bertkau distinguishes these two tribes by tlie presence in the Epc'iioids of what he calls a basal spot (Basaltieckj upon the mandibles. III. For the convenience of readers not acquainted with the anatomy of spiders, a general description of the animal is here given. It is not in ^ ;viR accord with the })urpose of this work to enter into the -SR details of ^structure ; for these the studies of anatomists .gr. and liistologists must be consulted. But some knowledge of the })rincipal organs, especially in their relations to the spinning industry, is necessary to the understanding ^ of much of what follows. The ])rincipal parts are the cephalothorax and abdo- men. The cephalothorax consists of the cephalic part *§ (cp. Fig. 11) and the thoracic part, tp ; the two parts Fig. 8. Face of Epeira. .^y^ uuitcd dircctly, aud uot by a neck, the caput being set innuediatcly upon the thorax, whence the name cephalothorax. The point of juncture is marked by a suture, more or less distinct, extending along the lower margin of the cai)ut backward, on eacli side, and con- verging in a depression more or less profound at the summit of the thoracic part. The cephalothorax is externally a hard, ehitinous case com])()Scd of two principal plates, resendjling more nearly than any other l)art of the body the tough shell of true insects. The front and up})er portion of the cephalic part is the cai)ut, which in Orbweavers is sometimes depressed, more frequently elevated. On the fore part of the ca})ut are situated eyes, which in this group are eight, but in other groups sometimes nmnber six and even two. The arrangement of the eyes upon the caput forms good generic and specific characters. The eyes in the Orbweavers are disposed across the caput in two rows of four each, known as front and rear rows (Fig. 8); they are again dividc