];-IANijBOOK of For Reference NOT TO BE TAKEN FROM THIS ROOM .^■■} Property of N. C. COLLEGE OF AGRICULTURE Department- of Zoology and Entonio!ogy No., Some early medical entomology. Athanasius Kircher's illustration of the Italian tarantula and the music prescribed as an antidote for the poison of its bite. (1643). HANDBOOK OF MEDICAL ENTOMOLOGY WM. A. RILEY, Ph.D. Professor of Insect Morphology and Parasitology, Cornell University and O. A. JOHANNSEN, Ph.D. Professor of Biology, Cornell University ITHACA, NEW YORK THE COIVISTOCK PUBLISHING COMPANY 1915 COPYRIGHT, I9I5 BY THE COMSTOCK PUBLISHING COMPANY, ITHACA, N. Y. Press of W. F. Humphrey Geneva, N. Y. PREFACE THE Handbook of Medical Entomology is the outgrowth of a course of lectiu^es along the lines of insect transmission and dissemination of diseases of man given by the senior author in the Department of EntomologA^ of Cornell University diuing the past six years. More specifically it is an illustrated revision and elaboration of his "Notes on the Relation of Insects to Disease" published January, 191 2. Its object is to afford a general survey of the field, and primarily to put the student of medicine and entomology in touch with the discoveries and theories which underlie some of the most important modem work in preventive medicine. At the same time the older phases of the subject — ^the consideration of poisonous and parasitic forms — have not been ignored. Considering the rapid shifts in viewpoint, and the development of the subject within recent years, the authors do not indulge in any hopes that the present text will exactly meet the needs of every one specializing in the field,- — still less do they regard it as complete or final. The fact that the enormous literature of isolated articles is to be foimd principally in foreign periodicals and is therefore difficult of access to many American w^orkers, has led the authors to hope that a summary of the important advances, in the form of a reference book may not prove unwelcome to physicians, sanitarians and working entomologists, and to teachers as a text supplementing lectiire work in the subject. Lengthy as is the bibliography, it covers but a ver}' small fraction of the important contributions to the subject. It will serve onh' to put those interested in touch with original sources and to open up the field. Of the more general works, special acknowledgment should be made to those of Banks, Bnimpt, Castellani and Chalmers, Comstock, Hewitt, Howard, Manson, Mense, Neveau-Lemaire, Nuttall, and Stiles. To the many who have aided the authors in the years past, by suggestions and by sending specimens and other materials, sincerest thanks is tendered. This is especially due to their colleagues in the Department of Entomology of Cornell University, and to Pro- fessor Charles W. Howard, Dr. John Uri Lloyd, Mr. A. H. Ritchie, Dr. I. M. Unger, and Dr. Luzerne Coville. VI Preface They wish to express indebtedness to the authors and publishers who have so willingly given permission to use certain illustrations. Especially is this acknowledgment due to Professor John Henry Comstock, Dr. L. O. Howard, Dr. Graham-Smith, and Professor G. H. T. Nuttall. Professor Comstock not only authorized the use of departmental negatives by the late Professor M. V. Slingerland (credited as M. V. S.), but generously put at their disposal the illus- trations from the Manual for the Study of Insects and from the Spider Book. Figures 5 and iii are from Peter's "Der Arzt und die Heilkunft in der deutschen Vergangenheit." It should be noted that on examining the original, it is found that Gottfried's figure relates to an event antedating the typical epidemic of dancing mania. Wm. a. Riley. Cornell University, Q. A. Johannsen. January, 191 5. CONTENTS CHAPTER I Early suggestions regarding the transmission of disease by insects. INTRODUCTION j_^ ADDITIONS AND CORRECTIONS vi line 1 1, for Heilkunft read Heilkunst. 6-56 18 line 2, for tarsi read tarsus. ;i2 line 21, and legend under fig. 23, for C. (Conorhinus) abdominalis read Melanolestes abdominalis. itrodectus. Other 47 legend under figure for 33c read 34. 92 line 22 and 25, for sangiusugus read sanguisugus. 116 legend under fig. 83, for Graham-Smith read Manson. 136 line 10, from bottom, insert "ring" after "chitin". 137 line 3, for meditatunda read meditabunda. 145 line 7, from bottom, for Rs read R,.. 158 line 20, for have read has. 212 after the chapter heading insert "continued". 219 line 10, from bottom, for Cornohinus read Conorhinus. 266 line I, fig. 158J refers to the female. 272 line 5, insert "palpus" before "and leg". 281 line 6, for discodial read discoidal. . or giant water- 281 last line, insert "from" before "the". • . . , 284 line 5, for "tubercle of" read "tubercle or". miptera reported 305 lines 19, 28, 44, page 306 lines i, 9, 22, 27, 30, page 307 line 7, page 309 lines 8, 1 1, for R4+5 read M^+^. 309 legend under fig. 168 add Bureau of Entomology. 312 line 36, for "near apex" read "of M,-i-j.". 313 rvmning head, for Muscidse read Muscoidea. 314 line 29, for "distal section" read "distally M^+^". 315 legend under fig. 172, for Pseudopyrellia read Orthellia, soning by nettling for Lvperosia read Hasmatobia, for Umbana read urbana. 323 and^325^^ legends under the figures, add "After Dr. J. H. ^^-^ ^lood plasma. 328 line 7 from bottom for Apiochaeta read Aphiochseta. PARASITIC ARTHROPODS AFFECTING MAN 57-130 Acarina, or mites. The TrombidiidcB, or harvest mites. The Ixodoidea, or ticks. Argasidas. Ixodidje. Treatment of tick bites. The mites. Dermanyssidae. Tarsonemid^e. Sarcoptidse, the itch mites. Demode- cidae, the follicle mites. Hexapoda, or true insects. vSiphunculata, or sucking lice. Hemiptera. VI Preface They wish to express indebtedness to the authors and publishers who have so wilHngh^ given permission to use certain illustrations. Especially is this acknowledgment due to Professor John Henry Comstock, Dr. L. 0. Howard, Dr. Graham-Smith, and Professor G. H. T. Nuttall. Professor Comstock not only authorized the use of departmental negatives by the late Professor M. V. Slingerland (credited as M. V. S.), b " "■"" ^""-^ "^ ^-^"--^ Hkt^ncinl the ilhis- trations from the Mant the Spider Book. Fig^ und die Heilkunft in de noted that on examinin figure relates to an exen mania. Cornell University, Januaty, 191 5. CONTENTS CHAPTER I INTRODUCTION 1-5 Early suggestions regarding the transmission of disease by insects. The ways in which arthropods may affect the health of man. CHAPTER II ARTHROPODS WHICH ARE DIRECTLY POISONOUS 6-56 The Araneida, or Spiders. The tarantulas. Bird spiders. Spiders of the genus Latrodectus. Other venomous spiders. Summary. The Pedipalpida, or whip-scorpions. The Scorpionida, or true scorpions. The Solpugida, or solpugids. The Acarina, or mites and ticks. The Myriapoda, or centipedes and millipedes. The Hexapoda, or true insects. Piercing or biting insects poisonous to man. Hemiptera, or true bugs. The Notonectidae or back-swimmers. Belostomidae or giant water- bugs. Reduviidae, or assassin bugs. Other Hemiptera reported as poisonous to man. Diptera; the midges, mosquitoes and flies. Stinging insects. Apis melliiica, the honey bee. Other stinging forms. Nettling insects. Lepidoptera, or butterflies and moths. Relief from poisoning by nettling larvs. Vescicating insects and those possessing other poisons in their blood plasma. The blister beetles. Other cryptotoxic insects. CHAPTER III PARASITIC ARTHROPODS AFFECTING MAN 57-130 Acarina, or mites. The Trombidiidse, or harv^est mites. The Ixodoidea, or ticks. Argasidae. Ixodidae. Treatment of tick bites. The mites. Dermanyssidae. Tarsonemidse. Sarcoptidae, the itch mites. Demode- cidae, the follicle mites. Hexapoda, or true insects. .Siphunculata, or sucking lice. Hemiptera. VIII Contents The bed-bug. Other bed-bugs. Parasitic Diptera, or flies. Psychodidse, or moth flies. Phlebotominae. Culicidfc, or mosquitoes. Simuliidse, or black-flies. Chironomidag, or midges. TabanidiE, or horse-flies. Leptidas or snipe-flies. Oestridas, or bot-flies. Muscidae, the stable-fly and others. Siphonaptera, or fleas. The fleas affecting man, the dog, cat, and rat. The true chiggers, or chigoes. CHAPTER IV ACCIDENTAL OR FACULTATIVE PARASITES 1^1-143 Acarina, or mites. Myriapoda, or centipedes and millipedes. Lepidopterous larvae. Coleoptera, or beetles. Dipterous larvae causing myiasis. Piophila casei, the cheese skipper. Chr>^somyia macellaria, the screw- worm fly. Calliphorinas, the blue-bottles. Muscinag, the house or typhoid fly, and others. Anthomyiidae, the lesser house-fly and others. Sarcophagidag, the flesh-flies. CHAPTER V ARTHROPODS AS SIMPLE CARRIERS OF DISEASE 144-163 The house or typhoid fly as a carrier of disease. Stomoxys calcitrans, the stable-fly. Other arthropods which may serve as simple carriers of pathogenic organisms. CHAPTER VI ARTHROPODS AS DIRECT INOCULATORS OF DISEASE GERMS 164-174 Some illustrations of direct inoculations of disease germs by arthropods. The r&le of fleas in the transmission of the plague. CHAPTER VII ARTHROPODS AS ESSENTIAL HOSTS OF PATHOGENIC ORGAN- ISMS 175-185 Insects as intermediate hosts of tape-worms. Arthropods as intermediate hosts of nematode worms. Filariasis and mosqui- toes. Other nematode parasites of man and animals. CHAPTER VIII ARTHROPODS AS ESSENTIAL HOSTS OF PATHOGENIC PRO- TOZOA 186-21 1 Mosquitoes and malaria. Mosquitoes and yellow fever. Contents IX CHAPTER IX ARTHROPODS AS ESSENTIAL HOSTS OF PATHOGENIC PRO- TOZOA 212-22y Insects and ttypanosomiases. Fleas and lice as carriers of Trypanosoma lewisi. Tsetse-flies and nagana. Tsetse-flies and sleeping sickness in man. South American trypanosomiasis. Leishmanioses and insects. Ticks and diseases of man and animals. Cattle tick and Texas fever. Ticks and Rocky Mountain Spotted fever of man. CHAPTER X ARTHROPODS AS ESSENTIAL HOSTS OF PATHOGENIC PROTO- ZOA (Continued) 230-240 Arthropods and Spirochsetoses of man and animals. African relapsing fever of man. European relapsing fever. North African relapsing fever of man. Other types of relapsing fever of man. Spirochetosis of fowls. Other spirochsete diseases of animals. Typhus fever and lice. CHAPTER XI SOME POSSIBLE, BUT IMPERFECTLY KNOWN CASES OF ARTHROPOD TRANSMISSION OF DISEASE 241-256 Infantile paralysis, or acute anterior poliomyelitis. Pellagra. Leprosy. Verruga peruviana. Cancer. CHAPTER XII KEYS TO THE ARTHROPODS NOXIOUS TO MAN 257-317 Crustacea. Myriapoda, or centipedes and millipedes. Arachnida (Orders of) . Acarina or ticks. Hexapoda (Insecta). Siphunculata and Hemiptera (lice and true bugs). Diptera (mosquitoes, midges, and flies). Siphonaptera (fleas). APPENDIX Hydrocyanic acid gas against household insects 318-320 Proportion of ingredients. A single room as an example. Fumigating a large house. Precautions. Lesions produced by the bite of the black-fly 321-326 BIBLIOGRAPHY 327-340 INDEX 341-348 CHAPTER I. INTRODUCTION EARLY SUGGESTIONS REGARDING THE TRANSMISSION OF DISEASE BY INSECTS Until very recent 3^ears insects and their allies have been considered as of economic importance merely in so far as they are an annoyance or direct menace to man, or his flocks and herds, or are injurious to his crops. It is only within the past fifteen years that there has sprung into prominence the knowledge that in another and much more insiduous manner, they may be the enemy of mankind, that they may be among the most important of the disseminators of disease. In this brief period, such knowledge has completely revolutionized our methods of control of certain diseases, and has become an import- ant weapon in the fight for the conservation of health. It is nowhere truer than in the case under consideration that how- ever abrupt may be their coming into prominence, great move- ments and great discoveries do not arise suddenly. Centuries ago there was suggested the possibility that insects were concerned with the spread of disease, and from time to time there have appeared keen suggestions and logical hypotheses along this line, that lead us to marvel that the establishment of the truths should have been so long delayed. One of the earliest of these references is by the Italian physician,. Mercurialis, who lived from 1530 to 1607, during a period when Europe was being ravaged by the dread "black death", or plague. Concerning its transmission he wrote: "There can be no doubt that flies feed on the internal secretions of the diseased and dying, then, flying away, they deposit their excretions on the food in neighboring dwellings, and persons who eat of it are thus infected." It would be difficult to formulate more clearly this aspect of the facts as we know them to-day, though it must always be borne in mind that we are prone to interpret such statements in the light of present-day knowledge. Mercurialis had no conception of the animate nature of contagion, and his statement was little more than a lucky guess. Much more worthy of consideration is the approval which was given to his view by the German Jesuit, Athanasius Kircher in 1658. 2 Introduction One cannot read carefiilly his works without beHeving that long before Leeuwenhook's discovery, Kircher had seen the larger species of bacteria. Moreover, he attributed the production of disease to these organisms and formulated, vaguely, to be sure, a theorv^ of the animate nature of contagion. It has taken two and a half centuries to accumulate the facts to prove his hypothesis. The theory of Mercuriahs was not wholly lost sight of, for in the medical literattire of the eighteenth century there are scattered references to flies as carriers of disease. Such a view seems even to have been more or less popularly accepted, in some cases. Gudger (1910), has pointed out that, as far back as 1769, Edward Bancroft, in "An Essay on the Natural History of Guiana in South America," wrote concerning the contagious skin-disease known as "Yaws": "It is usually believed that this disorder is communicated by the flies who have been feasting on a diseased object, to those persons who have sores, or scratches, which are uncovered; and from many observ^a- tions, I think this is not improbable, as none ever receive this disorder whose skins are whole." Approaching more closely the present epoch, we find that in 1848, Dr. Josiah Nott, of Mobile, Alabama, published a remarkable article on the cause of yellow fever, in which he presented "reasons for supposing its specific cause to exist in some form of insect life." As a matter of fact, the bearing of Nott's work on present day ideas of the insect transmission of disease has been very curiously overrated. The common interpretation of his theory has been deduced from a few isolated sentences, but his argtunent appears quite differently when the entire article is studied. It must be remembered that he wrote at a period before the epoch-making discoveries of Pasteur and before the recognition of micro-organisms as factors in the cause of disease. His article is a masterly refutation of the theory of "malarial" origin of "all the fevers of hot climates," but he uses the term "insect" as applicable to the lower forms of life, and specific references to "mos- quitoes," "aphids,"" cotton-worms," and others, are merely in the way of similes. But, while Nott's ideas regarding the relation of insects to yellow fever were vague and indefinite, it was almost contemporaneously that the French physician, Louis Daniel Beauperthuy argued in the most explicit possible manner, that yellow fever and various others are transmitted by mosquitoes. In the light of the data which were available when he wrote, in 1853, it is not stuprising that he erred by Early Suggestions 3 thinking that the source of the virus was decomposing matter which the mosquito took up and accidentally inoculated into man. Beau- perthuy not only discussed the role of mosquitoes in the transmission of disease, but he taught, less clearly, that house-flies scatter patho- genic organisms. It seems that Boyce (1909) who quotes extensively from this pioneer work, does not go too far when he says "It is Dr. Beauperthuy whom we must regard as the father of the doctrine of insect-borne disease." In this connection, mention must be made of the scholarly article by the American physician, A. F. A. King who, in 1883, brought together an all but conclusive mass of argument in support of his belief that malaria was caused by mosquitoes. At about the same time, Finley, of Havana, was forcefully presenting his view that the mosquito played the chief role in the spread of yellow fever. To enter more fully into the general historical discussion is beyond the scope of this book. We shall have occasion to make more explicit references in considering various insect-borne diseases. Enough has been said here to emphasize that the recognition of insects as factors in the spread of disease was long presaged, and that there were not wanting keen thinkers who, with a background of present-day conceptions of the nature of disease, might have been in the front rank of investigators along these lines. THE WAYS IN WHICH ARTHROPODS MAY AFFECT THE HEALTH OF MAN When we consider the ways in which insects and their allies may affect the health of man, we find that we may treat them under three main groups: A. They may be directly poisonous. Such, for example, are the scorpions, certain spiders and mites, some of the predaceous bugs, and stinging insects. Even such forms as the mosquito deserve some consideration from this viewpoint. B. They may be parasitic, living more or less permanently on or in the body and deriving their sustenance from it. Of the parasitic arthropods we may distinguish, first, the trtie parasites, those which have adopted and become confirmed in the parasitic habit. Such are the itch mites, the lice, fleas, and the majority of the forms to be considered as parasitic. In addition to these, we may distinguish a group of accidental, or facultative parasites, species which are normally free-living, feeding on 4 Introduction decaying substances, but which when accidentally introduced into the alimentary canal or other cavities of man, may exist there for a greater or less period. For example, certain fly larvae, or mag- gots, normally feeding in putrifying meat, have been known to occur as accidental or facultative parasites in the stomach of man. C. Finally, and most important, arthropods may be trans- mitters and disseminators of disease. In this capacity the^^ may function in one of three ways; as simple carriers, as direct inoculators, or as essential hosts of disease germs. As simple carriers, they may, in a wholly incidental manner, transport from the diseased to the healthy, or from filth to food, pathogenic germs which cling to their bodies or appendages. Such, for instance, is the relation of the house-fly to the dissemination of typhoid. As direct inoculators, biting or piercing species may take up from a diseased man or animal, germs which, clinging to the mouth parts, are inoculated directly into the blood of the insect's next victim. It it thus that horse-flies may occasionally transmit anthrax. Similarly, species of spiders and other forms which are ordinarily perfectly harmless, may accidentally convey and inoculate pyogenic bacteria. It is as essential hosts of disease germs that arthropods play their most important role. In such cases an essential part of the life cycle of the pathogenic organism is undergone in the insect. In other words, without the arthropod host the disease-producing organism cannot complete its development. As illustrations may be cited the relation of the Anopheles mosquito to the malarial parasite, and the relation of the cattle tick to Texas fever. A little consideration will show that this is the most important of the group. Typhoid fever is carried by water or by contaminated milk, and in various other ways, as well as by the house-fly. Kill all the house-flies and typhoid woiild still exist. On the other hand, malaria is carried only by the mosquito, because an essential part of the development of the malarial parasite is undergone in this insect. Exterminate all of the mosquitoes of certain species and the dis- semination of human malaria is absolutely prevented. Once an arthropod becomes an essential "host for a given parasite it may disseminate infection in three different ways : I. By infecting man or animals who ingest it. It is thus, for example, that man, dog, or cat, becomes infected with the double- pored dog tapeworm, Dipylidium caninum. The cysticercoid stage Arthropods and Man 5 occurs in the dog louse, or in the dog or cat fleas, and by accidentally ingesting the infested insect the vertebrate becomes infested. Simi- larly, Hymenolepis diminuta, a common tapeworm of rats and mice, and occasional in man, undergoes part of its hfe cycle in various meal- infesting insects, and is accidentally taken up by its definitive host. It is very probable that man becomes infested with Dracunculus (Filaria) tnedinensis through swallowing in drinking water, the crustacean, Cyclops, containing the larvae of this worm. 2. By infecting man or animals on whose skin or mucous mem- branes the insect host may be crushed or may deposit its excrement. The pathogenic organism may then actively penetrate, or may be inoculated by scratching. The causative organism of typhus fever is thus transmitted by the body louse. 3. By direct inoculation by its bite, the insect host may transfer the parasite which has undergone development within it. The malarial parasite is thus transferred by mosquitoes; the Texas fever parasite by cattle ticks. CHAPTER II. ARTHROPODS WHICH ARE DIRECTLY POISONOUS Of all the myriads of insects and related forms, a ^^ery few are of direct use to man, some few others have forced his approbation on accotmt of their wonderftd beauty, but the great hordes of them are loathed or regarded as directly dangerous. As amatter of fact, only a very, small ntmiber are in the slightest degree poisonous to man or to the higher animals. The result is that entomologists and lovers of nature, intent upon dissipating the foolish dread of insects, are sometimes inclined to go to the extreme of discrediting all statements of serious injury from the bites or stings of any species. Nevertheless, it must not be overlooked that poisonous forms do exist, and they must recei^^e attention in a consideration of the wa3^s in which arthropods may affect the health of man. Moreover, it must be recognized that "what is one man's meat, is another man's poison," and that in considering the possibilities of injury we must not ignore individual idiosyncrasies. Just as certain individuals may be poisoned by what, for others are common articles of food, so some persons may be abnormally susceptible to insect poison. Thus, the poison of a bee sting may be of varying severity, but there are individ- uals who are made seriously sick by a single sting, regardless of the point of entr>' . Some individuals scarcely notice a mosquito bite, others find it ven*' painful, and so illustrations of this difference in individuals might be multiplied. In considering the poisonous arthropods, we shall take them up by groups. The reader who is unacquainted with the systematic rela- tionship of insects and their allies is referred to Chapter XII. No attempt will be made to make the lists under the various headings exhaustive, but typical forms wnll be discussed. ARANEIDA OR SPIDERS Of aU the arthropods there are none which are more tmiversalh" feared than are the spiders. It is commonly supposed that the majority, if not all the species are poisonous and that they are aggres- sive enemies of man and the higher animals, as weU as of lower forms. That they really secrete a poison ma>' be readily inferred from the effect of their bite upon insects and other small forms. Moreover, Araneida or Spiders Head of a spider showing poison gland (c) and its re- lation to the chelicera (a). the presence of definite and well-developed poison glands can easily be shown. They occur as a pair of pouches (fig. i) lying within the cephalothorax and connected by a delicate duct with a pore on the claw of the chelicera, or so-called " mandible" on the convex surface of the claw in such a position that it is not plugged and closed by the flesh of the victim. The glands may be demonstrated by slowly and carefully twisting off a chelicera and pushing aside the stumps of muscles at its base. By exercising care, the chitinous wall of the chelicera and its claw may be broken away and the duct traced from the gland to its outlet. The inner lining of the sac is constituted by a highly developed glandular epithelitmi, supported by a basement membrane of connective tissue and covered by a musctdar layer, (fig. 2). The muscles, which are striated, are spirally arranged (fig. i), and are doubtless under control of the spider, so that the amount of poison to be injected into a wound may be varied. The poison itself, according to Robert (1901), is a clear, colorless fluid, of oily consistency, acid reaction, and ver\^ bitter taste. After the spider has bitten two or three times, its supply is exhausted and therefore, as in the case of snakes, the poison of the bite decreases quickly with use, until it is null. To what extent the content of the poison sacs may contain blood serum or, at least, active principles of serum, in addition to a specific poison formed by the poison glands themselves, Kobert regards as an open' question. He believes that the acid part of the poison, if reall}^ present, is formed by the glands and that, in the case of some spiders, the ferment -like, or better, active toxine, comes from the blood. But there is a wide difference between a poison which ma}' kill an insect and one which is harm- ful to men. Certain it is that there is no lack of popular belief and newspaper records of fatal cases, but the evidence regarding the possibility of fatal or even very serious results for man is most contradictory. For some years, we have attempted to trace the more circumstantial newspaper 3. Chelicera of spider. Section through a venom gland of Latrodectus 13-guttatus showing the peritoneal, muscu- lar and epithelial layers. After Bordas. 8 Poisonous Arthropods accounts, which have come to our notice, of injury by North American species. The results have served, mainly, to empha- size the straits to which reporters are sometimes driven when there is a dearth of news. The accounts are usually vague and lack- ing in any definite clue for locating the supposed victim. In the comparatively few cases where the patient, or his physician, could be located, there was either no claim that the injury was due to spider venom, or there was no evidence to support the belief. Rarely, there was evidence that a secondary blood poisoning, such as might be brought about by the prick of a pin, or by any mechani- cal injury, had followed the bite of a spider. Such instances have no bearing on the question of the venomous nature of these forms. The extreme to which unreason- able fear of the bites of spiders influenced the popular mind was evidenced by the accepted explana- tion of the remarkable dancing mania, or tarantism, of Italy during the Middle Ages. This was a ner- vous disorder, supposed to be due to the bite of a spider, the European tarantula (fig. 4), though it was also, at times, attributed to the bite of the scorpion. In its typical form, it was characterized by so great a sensibility to music that under its influence the victims indulged in the wildest and most frenzied dancing, until they sank to the ground utterly exhausted and almost lifeless. The profuse perspiring resulting from these exertions was supposed to be the only efficacious remedy for the disease. Certain forms of music were regarded as of especial value in treating this tarantism, and hence the name of " tarantella" was applied to them. Our frontis- piece, taken from Athanasius Kircher's Magnes sive de Arte Magnetica, 1643 ed., represents the most commonly implicated spider and illus- trates some of what Fabre has aptly designated as "medical choreography." The disease was, in reality, a form of hysteria, spreading by sym- pathy until whole communities were involved, and was paralleled by the outbreaks of the so-called St. Vitus's or St. John's dance, which The Italian tarantula (Lycosa tarantula). After Kobert. Araneida or Spiders • 9 swept Germany at about the same time (fig. 5). The evidence that the spider was the cause of the first is about as conclusive as is that of the demoniacal origin of the latter. The true explanation of the outbreaks is doubtless to be found in the depleted physical and mental condition of the people, resulting from the wars and the frightful plagues which devastated all Europe previous to, and during these times. An interesting discussion of these aspects of the question is to be found in Hecker. 5. Dancing mania. Illustration from Johann Ludwig Gottfried's Chronik. 1632. So gross has been the exaggeration and so baseless the poprdar fear regarding spiders that entomologists have been inclined to discredit all accounts of serious injury from their bites. Not only have the most circumstantial of newspaper accounts proved to be without foundation but there are on record a number of cases where the bite of many of the commoner species have been intentionally provoked and where the effect has been insignificant. Some years ago the senior author personally experimented with a number of the largest of our northern species, and with unexpected results. The first surprise was that the spiders were very unwilling to bite and that it required a considerable effort to get them to attempt to do so. In the second lo ' Poisonous Arthropods place, most of those experimented with were unable to pierce the skin of the palm or the back of the hand, but had to be applied to the thin skin between the fingers before they were able to draw blood. Unfor- tunately, no special attempt was made to determine, at the time, the species experimented with, but among them were Theridion tepi- dariorum, Miranda aurantia {Argiopa) ,Metargiope trifasciata, Marxia stellata, Aranea irifoUum, Misumena vatia, and Agelena ncBvia. In no case was the bite more severe than a pin prick and though in some cases the sensation seemed to last longer, it was probably due to the fact that the mind was intent upon the experiment. Similar experiments were carried out by Blackwell (1855), who believed that in the case of insects bitten, death did not result any 6. An American tarantula (Eurypelma hentzii). Natural size. After Comstock more promptly than it would have from a purely mechanical injury of equal extent. He was inclined to regard all accounts of serious injury to man as baseless. The question cannot be so summarily dismissed, and we shall now consider some of the groups which have been more explicitly implicated. The Tarantulas. — In popular usage, the term " tarantula " is loosely applied to any one of a ntmiber of large spiders. The famous tarantulas of southern Europe, whose bites were supposed to cause the dancing mania, were Lycosidce, or wolf-spiders. Though various species of this group were doubtless so designated, the one which seems to have been most implicated was Lycosa tarantula (L.), (fig. 4). On the other hand, in this country, though there are many Lycosidee, the term "tarantula" has been applied to members of the superfamily Avicularoidea (fig. 6), including the bird-spiders. Of the Old World Lycosidae there is no doubt that several species were implicated as the supposed cause of the tarantism. In fact, as we have already noted, the blame was sometimes attached to a scor- The Tarantulas ii pion. However, there seems to be no doubt that most of the accounts refer to the spider known as Lycosa tarantula. There is no need to enter into further details here regarding the supposed xarulence of these forms, popular and the older medical literature abound in circumstantial accounts of the terrible effects of the bite. Fortunately, there is direct experimental evidence which bears on the question. Fabre induced a common south European wolf-spider, Lycosa narhonensis , to bite the leg of a young sparrow, ready to leave the nest. The leg seemed paralyzed as a result of the bite, and though the bird seemed lively and clamored for food the next day, on the third day it died. A mole, bitten on the nose, succumbed after thirty- six hours. From these experiments Fabre seemed justified in his conclusion that the bite of this spider Is not an accident which man can afiford to treat lightly. Unforttmately, there is nothing in the experiments, or in the symptoms detailed, to exclude the probability that the death of the animals was the result of secondary infection. As far back as 1693, as we learn from the valuable account of Robert, (1901), the Italian physician, Sanguinetti allowed himself to be bitten on the arm by two tarantulas, in the presence of witnesses. The sensation was equivalent to that from an ant or a mosquito bite and there were no other phenomena the first day. On the second day the woimd was inflamed and there was slight ulceration. It is clear that these later symptoms were due to a secondary infection. These experiments have been repeated by various observers, among whom may be mentioned Leon Dufour, Josef Erker and Heinzel, and with the similar conclusion that the bite of the ItaHan tarantula ordinarily causes no severe symptoms. In this conclusion, Robert, though firmly convinced of the poisonous nature of some spiders, coincides. He also believes that striking symptoms may be simulated or arti- ficially induced by patients in order to attract interest, or because they have been assured that the bite, under all circiimstances, caused tarantism. The so-called Russian tarantula, Trochosa singoriensis (fig. 7), is much larger than the Italian species, and is much feared. Robert carried out a series of careful experiments with this species and his results have such an important bearing on the question of the venom- ous nature of the tarantula that we quote his summar\\ Experi- menting first on nearly a hundred living specimens of Trochosa singoriensis from Crimea he says that: Poisonous Arthropods "The tarantulas, no matter how often they were placed on the skin, handled, and irritated, could not be induced to bite either myself, the janitor, or the ordinary experimental animals. The objection that the tarantulas were weak and indifferent cannot stand, for as soon as I placed two of them on the shaved skin of a rabbit, instead of an attack on the animal, there began a furious battle between the two spiders, which did not cease until one of the two was killed." "Since the spiders would not bite, I carefully ground up the fresh animals in physiological salt solution, preparing an extract which must have contained, in solution, all of the poisonous substance of their bodies. While in the case of Latrodectus, as we shall see, less than one specimen sufficed to yield an active extract, I have injected the filtered extract of six fresh Russian taranttdas, of which each one was much heavier than an average Latro- dectus, subcutaneously and into the jugular vein of various cats without the animals dying or showing any special symptoms. On the basis of my experiments I can therefore only say that the quantity of the poison soluble in physiological salt solution, even when the spiders are perfectly fresh and well nourished, is very insignificant. That the poison of the Russian tarantula is not soluble in physiological salt solution, is exceedingly improbable. Moreover, I have prepared alcoholic extracts and was unable to find them active. Since the Russian spider exceeds the Italian in size and in intensity of the bite, it seems very improbable to me that the pharmacological test of the Italian tarantula would yield essentially other results than those from the Russian species." To the Avicularoidea belong the largest and most formidable appearing of the spiders and it is not strange that in the New World they have fallen heir to the bad reputation, as well as to the name of the tarantula of Europe. In this country they occur only in the South or in the far West, but occasionally living specimens are brought 7. Trochosa singoriensis. After Kobert. The Tarantulas 13 to our northern ports in shipments of bananas and other tropical produce, and are the source of much alarm. It should be mentioned, however, that the large spider most frequently fotind under such cir- cumstances is not a tarantula at all, but one of the Heteropodida;, or giant crab-spiders, (fig. 8). In spite of their prominence and the fear which they arouse there are few accurate data regarding these American tarantulas. It has S. The giant crab-spider or banana spider (.IltteropoJa venatoria). Natural size. After Comstock. £)ften been shown experimentally that they can kill small birds and mammals, though it is doubtful if these form the normal prey of any of the species, as has been claimed. There is no question but that the mere mechanical injury which they may inflict, and the consequent chances of secondary infection, justify, in part, their bad reputation. In addition to the injury from their bite, it is claimed that the body hairs of several of the South American species are readily detached and are urticating. Recently, Phisalix (191 2) has made a study of the physiological effects of the venom of two Avicularoidea, Phormtctopus carcerides Pocock, from Haiti and Cteniza sauvagei Rossi, from Corsica. The glands were removed aseptically and ground up with fine, sterilized sand in distilled water. The resultant liquid was somewhat viscid, colorless, and feebly alkaline. Injected into sparrows and mice the 14 Poisonous Arthropods extract of Phormictopus proved very actively poisonous, that from a single spider being sufficient to kill ten sparrows or twenty mice. It manifested itself first and, above all, as a narcotic, slightly lowering the temperature and paralyzing the respiration. Muscular and cardiac weakening, loss of general sensibility, and the disappearance of reflexes did not occur until near the end. The extract from Cteniza was less active and, curiously enough, the comparative effect on sparrows and on mice was just reversed. Spiders of the Genus Latrodectus. — While most of the popular accounts of evil effects from the bites of spiders will not stand investi- gation, it is a significant fact that, the world over, the best authentica- ted records refer to a group of small and comparatively insignificant spiders belonging to the genus Latrodectus, of the family Theridiidse. The dread " Malmigniatte" of Corsica and South Eiurope, the "Kara- kurte" of southeastern Russia, the "Katipo" of New Zealand the "Mena-vodi" and " Vancoho" of Madagascar, and our own Latrodectus mactans, all belong to this genus, and concerning all of these the most circumstantial accounts of their venomous nature are given. These accounts are not mere fantastic stories by luieducated natives but in many cases are reports from thoroughly trained medical men. The sjonptoms produced are general, rather than local. As smnmarized by Kobert (1901) from a study of twenty-two cases treated in 1888, in the Kherson (Russia) Government Hospital and Berislaw (Kherson) District Hospital the typical case, aside from complications, exhibits the following symptoms. The victim sud- denly feels the bite, like the sting of a bee. Swelling of the barely reddened spot seldom follows. The shooting pains, which quickly set in, are not manifested at the point of injury but localized at the joints of the lower limb and in the region of the hip. The severity of the pain forces the victim to the hospital, in spite of the fact that they otherwise have a great abhorrence of it. The patient is unable to reach the hospital afoot, or, at least, not without help, for there is usually inability to walk. The patient, even if he has ridden, reaches the hospital covered with cold sweat and continues to perspire for a considerable period. His expression indicates great suffering. The respiration may be somewhat dyspnoeic, and a feeling of oppression in the region of the heart is common. There is great aversion to solid food, but increasing thirst for milk and tea. Retention of urine, and constipation occur. Cathartics and, at night, strong spiders of the Genus Latrodectus 15 narcotics are desired. Warm baths give great relief. After three days, there is marked improvement and usually the patient is dis- missed after the fifth. This summan,' of s\TTiptoms agrees well -^-ith other trustworthy records. It would seem, then, that Riley and Howard (1889), who discussed a number of accounts in the entomological literature, were fully justified in their statement that "It must be admitted that certain spiders of the genus Latrodectus have the power to inflict poisonous bites, which may (probabh- exceptionally and depending upon excep- tional conditions) bring about the death of a htrman being." And yet, until recently the evidence bearing on the question has been most conflicting. The eminent arachnologist, Lucas, (1843) states that he himself, had been repeatedly bitten by the Malmigniatte without any bad effects. Dr. Marx, in 1890, gave before the Ento- mological Society of Washington, an account of a series of experiments to determine whether the bite of Latrodectus mactans is poisonous or not. He described the poison glands as remarkably small* and stated that he had introduced the poison in various ways into guinea-pigs and rabbits -wdthout obtaining an}^ satisfacton,' results. Obviously, carefully conducted experiments mth the supposed venom were needed and fortunately they have been carried out in the greatest detail by Kobert (190 1). This investigator pointed out that there were two factors which might account for the discrepancies in the earlier experiments. In the first place, the poison of spiders, as of snakes, might be so ex- hausted after two or three bites that further bites, following directly, might be without \'isible effect. Secondly, the application of the poison by means of the bite, is exceedingly inexact, since even after the most careful selection of the point of application, the poison might in one instance enter a little vein or lymph vessel, and in another case fail to do so. Besides, there would always remain an incalculable and very large amount externally, in the nonabsorptive epithelium. While all of these factors enter into the question of the effect of the bite in specific instances, they must be as nearly as possible obviated in considering the question of whether the spiders really secrete a venom harmful to man. *This is diametrically opposed to the findings of Bordas (1905) in the case of the European Latrodectus ij-guttatus, whose glands are "much larger than those of other spiders." From a considerable comparative study, we should also unhesitatingly make this statement regarding the glands of our American species, L. mactans. 1 6 Poisonous Arthropods Robert therefore sought to prepare extracts which would contain the active principles of the poison and which could be injected in definite quantities directly into the blood of the experimental animal. For this purpose various parts of the spiders were rubbed up in a mor- tar with distilled water, or physiological salt solution, allowed to stand for an hour, filtered, and then carefully washed, by adding water drop by drop for twenty-four hours. The filtrate and the wash- water were then united, well mixed and, if necessary, cleared by cen- trifuging or by exposure to cold. The mixture was again filtered, measured, and used, in part, for injection and, in part, for the deter- mination of the organic materials. Such an extract was prepared from the cephalothoraces of eight dried specimens of the Russian Latrodectus and three cubic centimeters of this, containing 4.29 mg. of organic material, were injected into the jugular vein of a cat weighing 2450 grams. The previously very active animal was paralyzed and lay in whatever position it was placed. The sensibility of the skin of the extremities and the rump was so reduced that there was no reaction from cutting or sticking. There quickly followed dyspnoea, convulsions, paralysis of the respiratory muscles and of the heart. In twenty-eight minutes the cat was dead, after having exhibited exactly the symptoms observed in severe cases of poisoning of man from the bite of this spider. These experiments were continued on cats, dogs, guinea pigs and various other animals. Not only extracts from the cephalothorax, but from other parts of the body, from newly hatched spiders, and from the eggs were used and all showed a similar virulence. Every effort was made to avoid sources of error and the experiments, con- ducted by such a recognized authority in the field of toxicology, must be accepted as conclusively showing that this spider and, presimiably, other species of the genus Latrodectus against which the clinical evi- dence is quite parallel, possess a poison which paralyzes the heart and central nervous system, with or without preliminary stimulus of the motor center. If the quantity of the poison which comes into direct contact with the blood is large, there may occur haemolysis and thrombosis of the vessels. On 1he other hand, check experiments were carried out, using similar extracts of many common European spiders of the genera Tegenaria, Drassus, Agelena, Eucharia and Argyroneta, as well as the Russian tarantula, Lycosa singoriensis. In no other case was the effect on experimental animals comparable to the Latrodectus extract. spiders of the Genus Latrodectus 17 Robert concludes that in its chemical nature the poison is neither an alkaloid, nor a glycoside, nor an acid, but a toxalbumen, or poison- ous enz}Tne which is very similar to certain other animal poisons, notably that of the scori)ion. 9. Latrodectus mactans (a) female, X 3; (b) venter of female; (c) dorsum of male. After Comstock. The genus Latrodectus is represented in the United States by at least two species, L. mactans and L. geometricus. Concerning L. mactans there are very circiimstantial accounts of serious injury and even death in man*. Latrodectus mactans \s coal black, marked with red or yellow or both. It has eight eyes, which are dissimilar in *Dr. E. H. Coleman (Kellogg, 1915) has demonstrated its virulence by a series of experiments comparable with those of Kobert. 1 8 Poisonous Arthropods color and are distinctly in front of the middle of the thorax, the lateral eyes of each side widely separate. The tarsi of the fourth pair of legs has a ntunber of curved setae in a single series. It has on the ventral side of its abdomen an hour-glass shaped spot. The full- grown female is about half an inch in length. Its globose abdomen is usually marked with one or more red spots dorsally along the middle line. The male is about half as long but has in addition to the dorsal spots, four pairs of stripes along the sides. Immature females resemble the male in coloring (fig. 9). Regarding the distribution of Latrodectus mac tans, Comstock states that: "Although it is essentially a Southern species, it occurs in Indiana, Ohio, Pennsylvania, New Hampshire, and doubtless other of the Northern States." L. geometricus has been reported from California. Other Venomous Spiders — While conclusive evidence regarding the venomous nature of spiders is meager and relates almost wholly to that of the genus Latrodectus, the group is a large one and we are not justified in dismissing arbitrarily, all accounts of injury from their bites. Several species stand out as especially needing more detailed investigation. Chiracanthium nutrix is a common European species of the family Clubionidse, concerning which there is much conflicting testimony. Among the reports are two by distinguished scientists whose accounts of personal experiences cannot be ignored. A. Forel allowed a spider of this species to bite him and not only was the pain extreme, but the general symptoms were so severe that he had to be helped to his house. The distinguished arachnologist, Bertkau reports that he, himself, was bitten and that an extreme, burning pain spread almost instantaneously over the arm and into the breast. There were slight chills the same day and throbbing pain at the wound lasted for days. While this particiilar species is not found in the United States, there are two other representatives of the genus and it is possible that they possess the same properties. We are unaware of any direct experi- mental work on the poison. Epeira diadema, of Europe, belongs to a wholly different group, that of the orb-weavers, but has long been reputed venomous. Kobert was able to prepare from it an extract whose effects were very similar to that prepared from Latrodectus, though feebler in its action. Under ordinary circumstances this spider is unable to pierce the skin of man Other Venomous Spiders 19 and though Kobcrt's results seem conclusive, the spider is little to be feared. Phidipptis audax (P. tripunctatus) is one of our largest Attids, or jumping spiders. The late Dr. O. Lugger describes a case of severe poisoning from the bite of this spider and though details are lacking, it is quite possible that this and other large species of the same group, which stalk their prey, may possess a more active poison than that of web-building species. Summary — It is clearly estabhshed that our common spiders are not to be feared and that the stories regarding their virulence are almost wholly without founda- tion. On the other hand, the chances of secondary infection from the bites of some of the more powerful species are not to be ignored. Probably all species possess a toxin secreted by the poison gland, virulent for insects and other normal prey of the spiders, but with little or no effect on man. There are a very few species, notably of the genus Latrodectus, and possibly including the Euro- pean Chiracanthium nutrix and Epeira diadema, which possess, in addition, a toxalbumen 10. A whip-scorpion (Mattigoproctus giganteus). dcrivcd from the general body Half natural size. After Comstock. .• 1 • -u • r ^ • 1 tissue, which is of great virulence and ma\' even cause death in man and the higher animals. TKE PEDIPALProA OR WHIP-SCORPIONS The tailed whip-scorpions, belonging to the family Thelyphonidae, are represented in the United States by the giant whip-scorpion Mastigopr actus giganteus (fig. lo), which is common in Florida, Texas and some other parts of the South. In Florida, it is locally known as the "grampus" or "mule-killer" and is very greatly feared. There is no evidence that these fears have any foundation, and Dr. Marx states that there is neither a poison gland nor a pore in the claw of the chelicera. Poisonous Arthropods THE SCORPIONroA, OR TRUE SCORPIONS The true scorpions are widely distributed throughout warm coun- tries and everywhere bear an evil reputation . According to Comstock (19 1 2), about a score of species occur in the Southern United States. These are comparatively small forms but in the tropics members of this group may reach a length of seven or eight inches. They are pre-eminently predaceous forms, which lie hidden during the day and seek their prey by night. The scorpions (fig. 11) possess large pedipalpi, terminated by strongly developed claws, or chelae. They may be distinguished from all other Arachnids by the fact that the dis- tinctly segmented abdomen is divided into a broad basal region of seven segments and a terminal, slender, tail-like division of five distinct segments. The last segment of the abdomen, or telson, terminates in a ventr ally-directed, sharp spine, and contains a pair of highly developed poison glands. These glands open by two small pores near the tip of the spine. Most of the species when running carry the tip of' the abdomen bent upward over the back, and the prey, caught and held by the pedipalpi, is stung by inserting the spine of the telson and allowing it to remain for a time in the wound. The glands themselves have been studied in Prionurus citrinus by Wilson (1904). He found that each gland is covered by a sheet of muscle on its mesal and dorsal aspects, which may be described as the compressor muscle. The muscle of each side is inserted by its edge along the ventral inner surface of the chitinous wall of the telson, close to the middle line, and by a broader insertion laterally. A layer of fine connective tissue completely envelops each gland and forms the basis upon which the secreting cells rest. The secreting epithelium is coliminar; and apparently of three different types of cells. I. The most numerous have the appearance of mucous cells, resembling the goblet cells of columnar mucous membranes. The nucleus, surroimded by a small quantity of protoplasm staining with haematoxylin, lies close to the base of the cell. A true scorpion. Comstock. After The True Scorpions 21 2. Cells present in considerable numbers, the peripheral por- tions of which are filled with very numerous fine granules, staining with acid dyes such as methyl orange. 3. Cells few in number, filled with very large granules, or ir- regular masses of a substance staining mth hcematoxylin. The poison, according to' Robert (1893), is a limpid, acid-reacting fluid, soluble in water but insoluble in absolute alcohol and ether. There are few data relative to its chemical nature. Wilson (1901) states that a common Egyptian species, Buthus qMinquestriatus, "has a specific gravity of 1.092, and contains 20.3% of solids and 8.4% ash. The venom of different species appears to differ not only quantita- tivel}' but qualitatively. The effects of the bite of the smaller species of the Southern United States may be painful but there is no satis- factory- evidence that it is ever fatal. On the other hand, certain tropical species are exceedingh'- virulent and cases of death of man from the bite are common. In the case of Buthus quinquestriatus , Wilson (1904) found the symptoms in animals to be hypersecretion, salivation and lachryma- tion, especially marked, convulsions followed by prolonged mus- ciilar spasm; death from asphyxia. The temperature shows a slight, rarely considerable, rise. Rapid and considerable increase of blood-pressure (observed in dogs) is followed by a gradual fall with slo^ving of the heart-beat. The coagulability of the blood is not affected. An interesting phase of Wilson's work was the experiments on desert mammals. The condition under which these animals exist must frequently bring them in contact with scorpions, and he found that they possess a degree of immunity to the venom sufficient at least to protect them from the fatal effects of the sting. As far as concerns its effect on man, Wilson foimd that much depended upon the age. As high as 60 per cent of the cases of children under five, resulted fatally. Caroroz (1865), states that in a Mexican state of 15,000 inhabitants, the scorpions were so abundant and so much feared that the authorities offered a bounty for their destruction. A result was a large number of fatahties, over two hundred per year. Most of the victims were children who had attempted to collect the scorpions. The treatment usually employed in the case of bites by the more poisonous forms is similar to that for the bite of venomous snakes. First, a tight ligature is applied above the wound so as to stop the 22 Poisonous Arthropods flow of blood and lymph from that region. The wound is then freely excised and treated with a strong solution of permanganate of potash, or with lead and opium lotion. In recent years there have been many attempts to prepare an antivenom, or antiserum comparable to what has been used so effectively in the case of snake bites. The most promising of these is that of Todd (1909), produced by the immunization of suitable animals. This antivenom proved capable of neutralizing the venom when mixed in vitro and also acts both prophylactically and cura- tively in animals. Employed curatively in man, it appears to have a very marked effect on the intense pain following the sting, and the evidence so far indicates that its prompt use greatly reduces the chance of fatal results. THE SOLPUOroA, OR SOLPUGmS The Solpugida are peculiar spider-like forms which are distin- guished from nearly all other Hs^///. \\ll!^/ arachnids by the fact that they possess no true cephalo- thorax, the last two leg-bear- ing segments being distinct, resembling those of the abdo- men in this respect. The first pair of legs is not used in locomotion but seemingly functions as a second pair of pedipalpi. Figure 12 illus- trates the striking peculiari- ties of the group. They are primarily desert forms and occur in the warm zones of all countries. Of the two hundred or more species, Comstock lists twelve as occurring in our fauna. These occur primarily in the southwest. The Solpugida have long borne a bad reputation and regarding virulence, have been classed with the scorpions. Among 'the effects of their bites have been A solpugid (Eremobates cinerea). stock. After Com- Mites and Ticks 23 described painful swelling, gangrene, loss of speech, cramps, deliri- um, unconsciousness and even death. Opposed to the numerous loose accounts of poisoning, there are a number of careful records by physicians and zoologists which indicate clearly that the effects are local and though they may be severe, they show not the slightest symptom of direct poisoning. More important in the consideration of the question is the fact that there are neither poison glands nor pores in the fangs for the exit of any poisonous secretion. This is the testimony of a number of prominent zoologists, among whom is Dr. A. Walter, who wrote to Kobert at length on the subject and whose conclusions are pre- sented by him. However, it should be noted that the fangs are very powerful and are used in such a manner that they may inflict especially severe wounds. Thus, there may be more opportunity for secondary infection than is usual in the case of insect wounds. The treatment of the bite of the Solpugida is, therefore, a matter of preventing infection. The wound should be allowed to bleed freely and then washed out with a 1 13000 solution of corrosive sublimate, and, if severe, a wet dressing of this should be applied. If infection takes place, it should be treated in the usual man- ner, regardless of its origin. THE ACARINA, OR MITES AND TICKS A number of the parasitic Acarina e\ndently secrete a specific poison, prestmiably carried by the saliva, but in most cases its effect on man is insignificant. There is an abundant literature dealing with the poisonous effect of the bite of these forms, especially the ticks, but until recently it has been confused by failure to recog- nize that various species may transmit diseases of man, rather than produce injury through direct poisoning. We shall therefore discuss the Acarina more especially in subsequent chapters, dealing with parasitism and with disease transmission. Nevertheless, after the evidence is sifted, there can be no doubt that the bites of certain ticks may occasionally be followed by a direct poisoning, which may be either local or general in its effects. Nuttall (1908) was unable to determine the cause of the toxic effect, for, in Argas persicus, the species most often implicated, he failed to get the slightest local or general effect on experimental animals, from the injection of an emulsion prepared by crushing three of the ticks. 24 Poisonous Arthropods It seems clearly established that the bite of certain ticks may cause a temporary paralysis, or even complete paralysis, involving the organs of respiration or the heart, and causing death. In 191 2, Dr. I. U. Temple, of Pendleton, Oregon, reported several cases of what he called "acute ascending paralysis" associated with the occur- rence of ticks on the head or the back of the neck. A typical severe case was that of a six year old child, who had retired in her usual normal health. The following morning upon arising she was unable to stand on her feet. She exhibited paralysis extending to the knees, slight temperature, no pain, sensory ner\^es normal, motor nerves completely parah'zed, reflexes absent. The following day the paral- ysis had extended to the upper limbs, and before night of the third day the nerv^es of the throat (hypoglossal) were affected. The thorax and larynx were involved, breathing was labored, she was unable to swallow liquids, phonation was impossible and she could only make low, gutteral sounds. At this stage, two ticks, fully distended with blood, were found over the junction of the spinal column with the occipital bones in the hollow depression. They were removed by the application of undiluted creoline. Though the child's life was despaired of, by the following morning she was very much improved. By evening she was able to speak. The paralysis gradually receded, remaining longest in the feet, and at the end of one week the patient was able to go home. There was some doubt as to the exact species of tick implicated in the cases which Dr. Temple reported, although the evidence pointed strongly to Dermacentor venustus* Somewhat later. Hadwen (19 1 3) reported that "tick paralysis" occurs in British Columbia, where it affects not only man, but sheep and probably other animals. It is caused by the bites of Dermacentor venustus and was experi- mentally produced in lambs and a dog (Hadwen and Nuttall, 19 13). It is only when the tick begins to engorge or feed rapidly, some days after it has become attached, that its saliva produces pathogenic effects. Ulceration following tick bite is not uncommon. In many of the instances it is due to the file-like hypostome, with its recurved teeth, being left in the wound when the tick is forcibly pulled off. *Accordmg to Stiles, the species occurring in the Northwest which is commonly identified as D. venustus should be called D. andersonii (see footnote, chapter 12). Centipedes and Millipedes 25 ^^ THE MYRIAPODA, OR CENTIPEDES AND MILLIPEDES The old class, Myriapoda includes the Diplopoda, or millipedes, and the Chilopoda, or centipedes. The pres- ent tendency is to raise these groups to the rank of classes. The Diplopoda The Diplopoda, or millipedes (fig. 13), are character- ized by the presence of two pairs of legs to a segment. The largest of our local myriapods belong to this group. They live in moist places, feeding primarily on decay- ing vegetable matter, though a few species occasion- ally attack growing plants. The millipedes are inoffensive and harmless. Julus terrestris, and related species, when irritated pour out over the entire body a yellowish secretion which escapes from cutaneous glands. It is volatile, with a pungent odor, and Phisalix (1900) has shown that it is an active poison when itte^ Comst^od^ injectcd into the blood of experi- mental animals. This, how- ever, does not entitle them to be considered as poisonous arthro- pods, in the sense of this chapter, any more than the toad can be con- sidered poisonous to man because it secretes a venom from its cuta- neous glands. The Chilopoda The Chilopoda,' or centipedes (fig. 14), un- like the millipedes, are predaceous forms, and possess well developed poison glands for kill- l*- 'J^^° common centipedes. • J r. • rr^-, (a) Lithobius forficatus. (6) Scutigera forceps. Natural mg tneir prey. These After Comstock. size; after Howard. 2 6 Poisonous Arthropods glands are at the base of the first pair of legs (fig. 15), which are bent forward so as to be used in holding their prey. The legs terminate in a powerful claw, at the tip of which is the outlet of the poison glands. The poison is a limpid, homogeneous, slightly acid fluid, which precipitates in distilled water. Briot (1904) extracted it from the glands of Scolopendra morsitans, a species common in central France, and found that it was actively venomous for the ordinary experimental ani- mals. A rabbit of two kilograms weight received an 15 Mandible of i^j^ction of thrcc cubic centimeters in the vein of the ear Scolopendra ^nd died in a minute. A white rat, weighing forty-eight cmgulata > & & j b showing prrams, received one and a half cubic centimeters in the V e n o m ° Dubo- ^^^^ hind leg. There was an almost immediate paralysis of the leg and marked necrosis of the tissues. As for the effect on man, there is little foundation for the fear with which centipedes are regarded. Our native species produce, at most, local symptoms, — sometimes severe local pain and swell- ing,— but there is no authentic record of fatal results. In the tropics, some of the species attain a large size, Scolopendra gigantea reaching a length of nearly a foot. These forms are justly feared, and there is good evidence that death sometimes, though rarely, results from their bite. One of the most careful accounts of death from the sting of the scorpion is that of Linnell, (1914), which relates to a comparatively small Malayan species, unfortunately undetermined. The patient, a coolie, aged twenty, was admitted to a hospital after having been stung two days previously on the left heel. For cure, the other coolies had made him eat the head of the scorpion. On admission, the patient complained of "things creeping all over the body". Temp. 102.8°. On the fourth day he had paralysis of the legs, and on the fifth day motor paralysis to the umbilicus, sensation being unaltered. On the sixth day there was retention of the urine and on the ninth day (first test after third day) sugar was present. On the thirteenth day the patient became comatose, but could be roused to eat and drink. The temperature on the following day fell below 95° and the patient was still comatose. Death fifteenth day. Examination of the spinal (lumbar) cord showed acute dissemi- nated myelitis. In one part there was an acute destruction of the anterior horn and an infiltration of round cells. In another portion Hexapoda, or True Insects 27 Clarke's column had been destroyed. The perivascular sheaths were crowded with small round cells and the meninges were con- gested. Some of the cells of the anterior horn were swollen and the nuclei eccentric; chromatolysis had occurred in many of them. As for treatment, Castellani and Chalmers (19 10), recommend bathing the part well with a solution of ammonia (one in five, or one in ten). After bathing, apply a dressing of the same alkali or, if there is much swelling and redness, an ice-bag. If necessary, hypo- dermic injections of morphine may be given to relieve the pain. At a later period fomentations may be required to reduce the local inflammation. THE HEXAPODA OR TRUE INSECTS There are a nimiber of Hexapoda, or true insects, which are, in one way or another, poisonous to man. These belong primarily to the orders Hemiptera, or true bugs; Lepidoptera, or butterflies and moths (larval forms); Diptera, or flies; Coleoptera, or beetles; and Hymenoptera, or ants, bees, and wasps. There are various ways in which they may be poisonous. 1. Piercing or biting forms may inject an irritating or poisonous sali^"a into the wound caused by their mouth-parts. 2. Stinging forms may inject a poison, from glands at the caudal end of the abdomen, into wounds produced by a specially modified ovipositer, the sting. 3 . Nettling properties may be possessed by the hairs of the insect. 4. Vescicating, or poisonous blood plasma, or body fluids are known to exist in a large number of species and may, under excep- tional circumstances, affect man. For convenience of discussion, we shall consider poisonous insects under these various headings. In this, as in the preceding discussion, no attempt will be made to give an exhaustive list of the poisonous forms. Typical instances will be selected and these will be chosen largely from North American species. PIERCING OR BITING INSECTS POISONOUS TO MAN Hemiptera Several families of the true bugs include forms which, while normally inoffensive, are capable of inflicting painful wounds on man. In these, as in all of the Hemiptera, the mouth-parts are modified 28 Poisonous Arthropods Muick of pump — '■^ •l.ahrwni ^ <5heathi' labium -*SeLa£-,-» ^fandtble and ^foxi^/oc Beak of hemipteron. to form an organ for piercing and sucking. This is well shown by the accompanying illustration (fig. i6). The upper lip, or labrum , is much reduced and immovable, the lower lip, or labium, is elongated to form a jointed sheath, within which the lance-like mandibles and maxillae are enclosed. The mandibles are more or less deeply serrate, depend- ing on the species concerned. The poison is elaborated by the salivary glands, excepting, possi- bly, in Belostoma where Locy is inclined to believe that it is secreted by the maxillary glands. The salivary glands of the Hemiptera have been the subject of much study but the most recent, comprehen- sive^work has been done by Bugnion and Popoff, (1908 and 1 9 10) to whose text the reader is referred for details. The Hemiptera have two pairs of salivary glands : the primary gland, of which the efferent duct leads to the salivary syringe, and the accessory gland, of which the very long and flexuous duct empties into the primary duct at its point of insertion. Thus, when one observes the isolated primary gland it appears as though it had efferent ducts inserted at the same point. In Nepa and the Fulgoridcs there are two accessory glands and therefore apparenth^ three ducts at the same point on the primary gland. The ensemble differs greatly in appearance in different species but we shall show here Bugnion and Popoff's figure of the apparatus of Notonecta ^^' s^HvTr^^pump'^LTFuT '^^cLCulata, d. specics capable of inflicting a painful &rn\td%^r bite on man (fig. 17). 17. Salivary glands of Notonecta maculata. After Bugnion and Popoff. Hemiptera, or True Bugs 29 Accessory to the salivary apparatus there is on the ventral side of the head, underneath the pharynx, a peculiar organ which the 19. Heteroptera, (a) Melanolestes picipes; (b) Notonecta undulata; (c.d) Aradus robustus (c) adult, (d) nymph, much enlarged; (e) Arilus cristatus; (/) Belostoma americana; (g) Nabis (Coriscus) subcoleoptratus, enlarged; (/») Cimex lectularius, (») Oeciacus vicarius, much enlarged; (j) Lyctocoris fitchii, much enlarged After Lugger. Germans have called the " Wanzenspritze," or syringe. The ac- companying figure of the structure in Fulgora maculata (fig. 18) shows its relation to the ducts of the salivary glands and to the beak. It is 30 Poisonous Arthropods made up of a dilatation forming the body of the pump, in which there is a chitinous piston. Attached to the piston is a strong retractor muscle. The function of the sahvary pump is to suck up the saliva from the salivary ducts and to force it out through the beak. Of the Hemiptera reported as attacking man, we shall consider briefly the forms most frequently noted. The Notonectidae, or hack swimmers, (fig. 196) are small, aquatic bugs that differ from all others in that they always swim on their backs. They are predaceous, feeding on insects and other small forms. When handled carelessly they are able to inflict a painful . bite, which is sometimes as severe as the sting of a bee. In fact, they are known in Germany as " Wasserbienen." The Belostomatidae, or giant water bugs, (fig. 19/) include the largest living Hemiptera. They are attracted to lights and on account of the large numbers which swarm about the electric street lamps in some localities they have deceived the popular name "electric light bugs." Our largest representatives in the northern United States belong to the two genera Belostoma and Banacus, distinguished from each other by the fact that Belostoma has a groove on the under side of the femur of the front leg, for the reception of the tibia. The salivary glands of Belostoma were figured by Leidy (1847) and later were studied in more detail by Locy (1884). There are two pairs of the glands, those of one pair being long and extending back as far as the beginning of the abdomen, while the others are about one-fourth as long. They lie on either side of the oesophagus. On each side of the oesophagus there is a slender tube with a sigmoid swelling which may serve as a poison reservoir. In addi- tion to this salivary system, there is a pair of very prominent glands on the ventral side of the head, opening just above the.,base of the beak. These Locy has called the "cephalic glands" and he suggests that they are the source of the poison. They are the homologues of the maxillary glands described for other Hemiptera, and it is by no means clear that they are concerned with the production of venom. It seems more probable that in Belostoma, as in other Hemiptera, it is produced by the salivary glands, though the question is an open one. The Belostomatidae feed not only on insects, but on small frogs, fish, salamanders and the like. Matheson (1907) has recorded the killing of a good-sized bird by Belostoma americana. A woodpecker, Hemiptera, or True Bugs 31 or flicker, was heard to utter cries of distress, and fluttered and fell from a tree. On exam- ination it was found that a bug of this species had inserted its beak into the back part of the skull and was apparently busily engaged in sucking the blood or brains of the bird. Various species of Belostoma have been cited as causing painful bites in man. We can testify from personal experience that the bite of Belostoma americana may almost immedi- ately cause severe, shooting pains that 20. Reduvius COpsicoetus) personatus. (x2). may extend through- out the arm and that they may be felt for several days. Relief from the pain may be obtained by the use of dilute ammonia, or a menthol ointment. In the not uncommon case of secondary infection the usual treatment for that should be adopted. The ReduviidaB, or assassin-hugs are cap- able of inflicting very painful wounds, as most collect- ors of Hemip- tera know to their '» 1- '^m ..^^' '»i 4 ^-4 %^: n f ^ W •;'\ 5| * •