ee mit ats ind b tee \ ” *S % ay, l uM eG) " * + x aay Mi + * ij 4 y eR NS = = sy ‘ic j 3 BOUGHT WITH THE INCOME OF THE THE GIFT OF HENRY W. SAGE Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004082289 The house or typhoid fly, Musca domestica. Greatly enlarged. (Howard and Pierce, photo by Dovener.) S A N ITA RY ENTOMOLOGY THE ENTOMOLOGY OF DISEASE, HYGIENE AND SANITATION EDITED BY WILLIAM DWIGHT PIERCE, Pu.D. Consulting Entomologist, formerly Entomologist Southern Field Crop Insect Investigations United States Department of Agriculture, Bureau of Entomology WI wea ¢\f ARTI AVERTATIN BOSTON RICHARD G. BADGER THE GORHAM PRESS CORNREL UNIVER GIDDY as LIE RAR Y Copyricat, 1921, py Ricnarp G. BapGER All Rights Reserved Made in the United States of America The Gorham Press, Boston, U.S. A. TO Dr. LELAND OSSIAN HOWARD CHIEF OF THE BUREAU OF ENTOMOLOGY, THIS BOOK IS DEDICATED TO HIM, MORE THAN TO ANY ONE ELSE, DO ENTOMOLOGISTS OWE THE PRACTICAL DEVELOPMENT OF THEIR SCIENCE, WHICH TOUCHES UPON EVERY HUMAN ACTIVITY. HE STOOD AMONG THE FIRST TO EMPHASIZE THE IMPORTANCE OF SANITARY ENTOMOLOGY. HE STANDS NOW THE CHIEF EXPONENT OF ENTOMOLOGY THROUGHOUT THE WORLD. FOREWORD In May, 1918, a class was formed among the entomologists of the country to study the recent developments in the entomology of disease, hygiene, and sanitation, for the purpose of equipping themselves for any special service which they might be called upon to render during the war. The lectures were mimeographed week by week and mailed to the enrolled membership, which numbered in excess of 500. The war emergency is over and the mimeographed lectures have practically all been distributed. These lectures, however, dealt as much with domestic as with military problems, and they have now been com- pletely revised up to date of March 1, 1919, and are given forth as'a series of lectures dealing with the entomological problems of peace times from the standpoint primarily of municipal, industrial, and household problems, and also with the hope that the course will be of assistance to teachers, and will: stimulate research among investigators. Many important topics have been omitted, for we cannot hope to present the whole subject in a book of this size. This phase of entomology is one which is destined to become very important as our knowledge of disease transmission increases. There are many unworked and insufficiently worked problems now in sight, and these lectures will be found to suggest numerous possible lines of research. I wish at this time to express my appreciation of the services of Mr. Jacob Kotinsky, who served as Secretary of the Class, and of my collaborators in this course of lectures. As nearly as possible the International Rules of Nomenclature are followed, but in Entomology the practice had not been followed of en- closing the original author’s name in parenthesis followed by the name of the author responsible for the present combination, and it has been impossible in the present volume to obtain all of the necessary information, W. Dwicut Pierce. CONTENTS CHAPTER PAGE JT. How Insects Can Carry or Cause Disease. . . ea a 19 CuassiFIcaTION oF MetuHops sy Waic# Insects Can Cunt or Cause DIsfasSE. . . ws ap (ah 20 Way It Is Nacewane: TO row Hoy Tassos Game Dicenes nive jx 1388 II. Some Necessary Steps 1n Any Arrempt to Prove Insect TRANSMISSION OR Causation oF DISEASE . . . ; 3 So de 2, Ay uphse, RRA & oj 225: I. CooprraTION . . 25 II. Were SHOULD THE Tvaarieannnnes OF _— Ae MIaRION Brcin? 26 III. Puan or OperaTIoN . . . vs, agile. eS) ee ay ae BE IV. How Swati We Recorp Our Oadanaaamona? ‘: «= 27 V. How Can an Insect se INvoLvED 1n Disease Tpiuaumcian? Q7 1. What Kind of Organisms Can Insects Carry? . . s « 87 2. In What Manner May Insect Toxins Bring About Disease? . . 27 3. Can Insects Themselves Cause Disease? . 28 4. Where May Insects Obtain the Organisms Which Cause Disease? 28 5. How Can the Insect Transmit the Organism? . . . - 28 6. What is the Course of the Organism in the Insect? . . 29 7. What is the Course of the Organism on Leaving the Insect? . 29 VI. Waat 1s Known Asout THE Disease To BE INVESTIGATED? . . 30 VII. Wuat Insects SHovutp BE INVESTIGATED? . . . _ 30 VIII. Waat 1s NeEcEsSsARY IN THE TRANSMISSION Riccuienwe? wa Sl IX. How SHoutp Exprerimentau Insects BE HANDLEDP ..... 82 Ill. A Gewnerat Survey or tHe Neeps or Entomo.ocicaL SANITATION IN AMERICA. . Fi Be any See. es eh fiat den es aoweodh, Bh ap, onl: OR THE Taonwenei Beau a & zi i a Os os Ses . 85 How to Improve Farm Saniwariont {6 2 4 w 24 gon ee we a we SE Tue Insanirary TowN ...... . ee ee ew ee ee ee 8B How to Improve SANITATION . . . . . ee ee ee ee ee BB Sanitary PRoBLEMS OF CITIES. i dn em Be ob 39 ENTOMOLOGICAL REQUIREMENTS OF ees Si migkiian ees atte 40 INDUSTRIAL SANITATION . 1. 7 ee eee ee ee ee ee A IV. A GeneRat SuRVEY of THE SERIOUSNESS OF INSEcT Borne DisEasEs TO ARMIBS: ek Gla) a ea ee AP eo eG es ee) Geet ay ee AB Y. Rewation or Insects To THE Parasitic WorMS OF VERTEBRATES . . . 50 Mops or Inrection or Insect Hosts. ............ ~ «51 Mope or InrecTION oF VERTEBRATE Hosts. ....... =. . 52 Species or Worms Founp in INSEcTS. . . . . . 2. 1 wee
be & ae 228 Horse Flies . . . . 2... a. Geos ; Rrias ea eeS Famity Muscip2 . . As by en ty Goi Me eO Bloodsucking Fly Larve |. . : en te 228 Biting Species of Musca . be oe Bee Roe or Boe ee Bw oe 289 True Biting Flies . . . 5 teak Re cM ee age ee 229 Stable Flies . . iS tek > be in ae ryan es 230 CONTENTS CHAPTER Horn Flies . . . . Tsetse Flies . ‘ PurIpaRA .. REFERENCES ..... XVI. Brotocy anp Hasits or Horse Futes Eees anp Eco Layine Larvaé Purz. Lire CrciEe 7 Hasits or ADULTS . : CONCERNING CONTROL Miaaoans BIBLIOGRAPHY XVII. Diseases TRANSMITTED BY Mosquitos Diseases oF UNCERTAIN OrIGIN TRANSMITTED BY hosaurress Piant Orcanisms TRANSMITTED BY MosquiToEs Thallophyta: Fungi... ....... Thallophyta: Fungi: Schizomycetes: Bacteriacee. ANIMAL OrcaNIsMS TRANSMITTED BY ai Protozoa bee th. oct Mastigophora: Binucleata: Hemoproteide - é Mastigophora: Binucleata: Leucocytozoids Mastigophora: ‘Binucleata: Trypanosomidee Mastigophora: Binucleata: Leptomonid Mastigophora: Binucleata: Plasmodide . . Mastigophora: Spine aee Spirochetidee Metazoa . . ee 2 Platyhelmia: " Fasciolidze ee Nemathelminthes: Nematoda: Filariide . Nemathelminthes: Nematoda: Mermithide REFERENCES XVIII. Wasat We SHovutp Know Asovur Moseuiro BioLocy OviposiTION AND THE Eco Stace Tae Larva anp THEIR Hasits Toe Pure. .. Aputt MosquITors Table of American Disease-Carrying Mosquitoes REFERENCES XIX. Moseurro ControL PREVENTION OF Mesauns Banmine Scouting . Determination of Source of Mosquitoes Leveling and Filling Water Holes Ditching and Clearing Streams and Swamps Clearing of Weed E Filled ie and Lakes . Drainage . 5 Larvicides Oiling . : Artifeial Containers of Mosquito ‘Larve Fish as Mosquito Control ; Destruction of Adult Mosquitoes, Protection From Mosqu!TorEs ; F Protection of Dwellings from Mosquitoes : Protection of the Individual ee BIBLIOGRAPHY xili PAGE 232 234 235 235 236 237 240 243 243 244 245 246 Q47 248 249 249 249 249 249 249 250 250 251 252 259 260 260 261 262 263 266 267 268 272 272 273 274 275 275 275 276 276 276 Q77 277 279 280 282 282 283 283 283 283 285 xiv CONTENTS CHAPTER XX. Louse Borne Diskases . . . Bo ssersnay Ge arate SE I. Dimect Errect or Louse Ruwaer , 1. Types of Pediculosis Corporis 2. Types of Pediculosis Capitis 3. Types of Phthiriasis 4. Effects of Attack of Other Lice II. Transmission or Diseases BY Lice 1. Diseases of Plant Origin . . . . ......., Thallophyta: Fungi: Ascomycetes: Gymnoascee . Thallophyta: Fungi: Hyphomycetes ok Thallophyta: Fungi: Schizomycetes: Coccacee . Thallophyta: Fungi: Schizomycetes: Bacteriacez Summary of Plant-Caused Diseases A We id 2. Diseases of Unknown or Uncertain Origin . 3. Diseases of Animal Origin ree Protozoa ‘ Mastigophora: “Binucleata: Trypanosomide Mastigophora: Binucleata: Leptomonide . . Mastigophora: Spirochztacea: Spirochetide . Telosporidia: Heemogregarinida: Hzeemogregarinide DM ebazog es. oN Sel Sh ge ik BN oe ss wos Hee es Platyhelmia: Cestoda: Cyclophyllidea: Teeniidse BIBLIOGRAPHY ae Ee SR a a XXI. Tue Lire History or Human Lice REFERENCES XXII. Tue Conrrot or Human Lice Tue Ravaces or Lice E Reservorrs or Louse BREEDING . Controt MEasuREs F Controu or Lick on THE Bopy Control of Crab Louse Control of Head Louse . Control of Body Louse Controu or Lick 1n CLoTHING 1. Laundry. . . Dry Cleaning . Steam Sterilization . Hot Air Delousing . Fumigation . . Storage ‘4 . Impromptu Delousing Arrangements Controu or Lick in Livinc QUARTERS Controu or Lice 1n Hospitats Control of Lice in Hospitals. Louse-Proof Garments for Medical Attendants, ete. EOD St Be 09 2 BisuiockaPHY . . . 2... XXIII. Lice Wuicn Arrect Domestic ANIMAIS. ....... Part 1. Carrie Lick anp THerr ContRoL. ...... Sucking Licés. Gin he 4 Re eS ee we we mS Biting Lice . . a 2 RS ORR ee OS Methods of Study of Life History a BR ORS Baul ase, Mad oie 2s Control Measures . . . Bey a Lae case thy tay ake 1G Seat etter Oils. ec ae ae os be Ges, ah Ser, gatucthe ~9n be Wa bt-roe eh tees Sprays . Ss tee) are ein xe Gace ee ea Miscellaneous Remedies oo a he Se Time for the eyoueaim of Control Measures | ae ae ae Skin Injuries .. ae wae. abe eg eee Gee ee ec ae 1 PAGE 286 286 286 287 287 288 289 289 289 289 289 290 290 291 294 294 294 294 295 296 297 297 297 301 311 312 312 313 314 316 316 316 317 319 319 320 321 324 324 326 326 327 328 328 328 328 330 330 331 332 333 334 334 335 337 338 338 CONTENTS CHAPTER Part 2. Lick Arrectinc Cuicxens, Hoes, Goats, SHEEP, HorsEs, AND Orner ANIMALS Lice Infesting Domestic Fowls . . . Lice Infesting Rabbits, Cats and ions The Hog Louse. . . . : Lice Attacking Sheep. . . Biting and Sucking Lice of Goats. Lice of the Horse : Important Bibliographical References XXIV. Diseases CarrRiep BY FLEAS Puant OrcanismMs TRANSMITTED BY Peas doe Thallophyta: Fungi: Schizomycetes: Bacteriacexr . ANIMAL ORGANISMS Eeéneuiraen By Firas . Protozoa : Mastigophora: Binucleata: " ‘Trypanosomidee 3 Mastigophora: Binucleata: Leptomonide ‘ Mastigophora: Spirochetacea: Spirochetide . Telosporidia: Gregarinida: Agrippinide . ‘ .Telosporidia: Heemogregarinida: Hemogregarinide Metaz0ag = 6s. ee Platyhelmia: Cestoidea: Cyclophillidea: “Teniidee Platyhelmia: Cestoidea: Cyclophillidea: Hymenolepidide Nemathelminthes: Nematoda: Spiruride Nemathelminthes: Nematoda: Filariide SumMMARY REFERENCES XXV. Tue Lire History anp Controu or FiEas Factors Inrtuencine ABUNDANCE OF FLEaAs Controu oF Fieas. . . . . List or REFERENCES é ‘ Notes oN THE CHIGOE, Dumecwennge Pinsiaens 5 KXVI. CockroacHEs BroLocy ‘ Key To THE Four PRinctPaL Plousinoun CocKROACHES Blatta orientalis (Linnzus) , Blattella germanica (Linneus), Caudell _ Periplaneta americana (Linnzus) ; Periplaneta australasie (Fabricius) Burmeister REMEDIES z Fumigation . . Hydrocyanic Acid Gas Carbon Bisulphide . Pyrethrum Powder . Sulphur . Poisons ‘ Sodium Fluoride. Borax . . Pyrethrum Powder . Phosphorus bit dew BS raow & Sulphur... 20s gg we ky aoe 8, Castor Oil . ‘ Al 32 g Pphe. e. aah Traps... ENEMIES XXVII. Diseases TRANSMITTED BY THE COCKROACH ...... Puant ORGANISMS . . «ee ee ee ee te et Thallophyta: Fungi: Coccacee . Thallophyta: Fungi: Bacteriacee . Thallophyta: Fungi: Spirallacese . xv PAGE 339 339 343 344 345 346 347 348 350 350 350 352 352 352 354 355 355 355 355 355 356 357 357 357 358 360 366 367 371 373 374 375 376 376 377 378 380 380 380 380 380 381 381 381 381 381 382 382 382 382 382 382 383 383 383 384 387 XVI CONTENTS CHAPTER PAGE AnmmMaL ORGANISMS... ww ee eee ee ee 888 Protozoa . . Sue Thy op ie oe Gat ayy et GE Oa aps Ca 7988, Sarcodina: Ameebina: Ameebidee dinid iy bs abe ; . . 3888 Mastigophora: Polymastigina: Tetramitide a) & Ge & Bole ~ 388 Mastigophora: Binucleata: Leptomonide . . ‘4 . . 388 Telosporidia: Gregarinida: Gregarinide . . . . . a3 . 388 Telosporidia: Coccidiidea: Eimeriide. ....... =... +. 388 Neosporidia: Myxosporidia: Thelohaniide . bes ee . 388 Ciliata: Heterotricha: Bursarinide . . . .... 2... . 3888 Metazoa . . aes ee 8 . 389 Platyhelmia: " Cestoidea: " Hymenolepididee be er : 389 Nemathelminthes: Acanthocephala: Gigantorhynchide 5 389 Nemathelminthes: Nematoda: Spiruride . . Se eae ad . 389 Nemathelminthes: Nematoda: Oxyuride . . ; ‘ 389 REFERENCES . . . 1. ee ee te abate ee oe Bn ae BODE XXVIII. Tot Bepsue anp OruEeR Buioopsuckine Bucs: Disrases TRANSMITTED, Biotocy anp ConTRoL . . . So @ ao & BOT DIsEASES OF THE PLANT Rerason oP easneanernarnts BY — ; . . 892 Thallophyta: Fungi: Bacteriacee. . . . i A . 392 Diseases OF UNKNOWN ORIGIN . . oo ye 898 DIseases OF THE ANIMAL KINGDOM We anapiiaatiy + BY Beas iw 393 Protozoa . . ‘ : . 3893 Mastigophora: Binucleata: " ‘Trypanosomidz . ayo tn ae 2898 Mastigophora: Binucleata: Leptomonide . . ; » . . 895 Mastigophora: Spirochetacea: Spirochetide ‘ . 398 lire History Notes ..... . eh wees ace . . . . 899 TREATMENT OF BriTEs digs Ce ais . 401 ControL Measures. Foe ae a 3 ; . 401 List or REFERENCES . ...... é Bao we oe C4OR XXIX. Diseases CausepD on Carriep By Mites anp Ticks . . é . 403 Diseases Causep BY Direct ATTACK oF Ticks anp MITES . . 403 Diseases CarrieD BY Mites anp Ticks . .......... . All Diseases Causep BY Puant OrcGanismMs . . . 411 Disrases OF UNKNOWN ORIGIN . . . aes a Mg eae Gre ee ee TD Disnases or ANIMAL ORIGIN... ... . ‘ oe we 414 Protozoa . . F . 414 Mastigophora: Binucleata: Trypanosomide D4 . 414 Mastigophora: Binucleata: Leptomonide .. . . 414 Mastigophora: Spirochetacea: Spirochetide oe ~ « 9 « 418 Telosporidia: Hemogregarinida: Hemogregarinide ee ee ee 420 SumMary ... ne fees Ses te be dee Pa eas 424 List oF Ransannows ee ee S. & ey Se an a . 427 XXX. Tue Biotocies anp Hasits or Ticks. - eer ; . 430 BrstiocrRapHic REFERENCES ........ . 2... ee « « 488 XXXI. Conrrout or Ticks . . 2 Be) as d - 2 . 440 List or REFERENCES .... . . £o as 2 : ~ ee 449 XXXII. Furies anp Lice 1n Ecrypr a eee ee : ‘ os « w « « 450 Tue Suvran’s FUNERAL . . . .. . 1 + ee eee ee we 5% XXXIIIJ. Insects in Revation to Packine Housps . ..... . soe a » 453 Insect-BREEDING Places AND THEIR TREATMENT. . ... . . . 455 Protection Acainst INSECTS . . . . 458 A BretiocraPrHy oF LITERATURE Dima WITH ‘Sacnaron OF ‘Maar Packinc EstaBLISHMENTS ... . ty CB ode) Rk Se ge oe oe HOD CONTENTS XVil CHAPTER PAGE XXXIV. Insect Porsoninc aND MisceLLANgous Notes ON THE TRANSMISSION OF Diseases By INSECTS. 2 6. we ee ee ee ee 461 Scorpion PoIsonING ..... . eo Soe ee @ =e w AGE SprperR PoIsonIng . .... . 1. ee et woe eee 463 CentIpepDE Poisoning. . 2 1 1 ee ee ee ee AB CrentTIPEDES IN Nasa Cavities AND ALIMENTARY CANAL Lee ee 466 Lerrpoprerous Larv@ Poisoning . . . 1 ee ee ee ee 466 Ber, Wasp anp Ant STINGS. na 8 ye Se Bees. 4 UACT Honey Poisoning . . . . . we ee Ae e 4 we & o 468 ANAPHYRAXIS. § ¢ 2 8 4 @ oe 8 8 we * Bom 6 8 we we oe e BOB Potsoninc From Eating Insects. . . . .. .- - oe . . . 469 Kissing BUGS « + @ 2 | @ % @ @ As # © % He % e a e w SED Dermatitis Causep BY BEETLES. . . . 1. ee ee ee . . 469 BEETLES AS CARRIERS OF DisEasE GERMS ... . «eo we ee 409 List or REFERENCES . . . ... 1... a & Coho e « 4 AMO SUMMARY 4 «© « %© w@ # # @ @ BF @ H&B a eS Sy ue wy A XXXV. A Tasutation or Diseases anD InsEcT TRANSMISSION . be oe a ey AS INDEX: 45? ede wide ae aA BR Soles Bae ee ke A a SOD CONTENTS BY AUTHORS By W. Dwicut Pierce—Bureau of Entomology How Insects Can Carry or Cause DISEASE LEAs od) GEL ty oti 32 Some Necessary Steps rn ANY ATTEMPT TO Prove INSECT TRANSMISSION OR CAUSATION OF DiskasE . . ww ww A GENERAL Survey or THE NrEps or ENTOMOLOGICAL SANITATION IN AMERICA A GENERAL SuRVEY orf THE SERIOUSNESS OF INSECT BorNE DisEASES TO ARMIES RELATIONS OF CLIMATE AND LIFE, AND THEIR BEARINGS ON THE Stupy or Mepicau Ento- MOLOGY?! “Ys eee gn Be) ees Oy BSB tee EH. HO aS Diseases Borne By Non-Bitinc Furs . . . . 1. 0.0.0. ee ew es Important Puases in THE Lire History or THE Non-Bitinc Furs .... . Tae Controu or tHe House Fry ann Revatep Fumes . ......~. Diseases TRANSMITTED BY BLoopsucKING FLIEs n> oyihe “Th Ba Sis te Ge Watt ne A TaBULATION oF Diseases AND INSECT TRANSMISSION . . . «© «©. ew By W. Dwicut Prerce anv C. T. Greene, Bureau of Entomology Wauat We Saovutp Know Asour Mosquito BioLocy By W. Dwicut Pierce anp Rosert H. Hurcurison, M.A., Bureau of Entomolo;y Tae Lire History or Human Lice oe ORES Re ay ae ae a Tae Controyt or Human Lick . . . . . . ee et By B. H. Ransom, Pu.D., Zoologist, Bureau of Animal Industry RexLation or Insects To THE Parasitic WorMS OF VERTEBRATES . . . By F. C. Bisorer, B.S., Bureau of Entomology, In Charge Animal Insect Investigations Controu or Fires 1n Barn Yarps, Pic Pens AND CHICKEN YARDS. . . Myzasis. Types or Injury anp Lire History anp Hasits or Species CoNcERNED xix PAGE 19 25 34 43 97 105 126 152 209 223 247 275 286 350 383 391 403 461 473 266 301 312 50 167 175 XX CONTENTS BY AUTHORS Myiasis. Irs PREVENTION AND TREATMENT Tue Lire History ann Conrrou or FiLEas Tae Biotocres anp Hasits or Ticks THE Controu or Ticks By J. L. Wess, M.S., Bureau of Entomology Brotocy anp Hasits or Horse Firs . By G. H. Lamson, Jr., M.S., Entomologist Storrs (Conn.) Agricultural Experiment Station Lice Waica Arrect Domestic ANIMALS By A. N. Caupett, B.S., Bureau of Entomology: Curator of Orthoptera, U. S. National Museum CocKROACHES By H. A. Battov, Pu.D., Imperial Entomologist, Barbados Fires anp Lice in Ecypr By E. W. Laake, B.S., Bureau of Entomology Insects In Revation ro Packine Houses PAGE 200 360 430 440 236 330 374 450 453 LIST OF TEXT FIGURES FIGURE 1. 2. 3. 4. 5. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. Cross Section or Mann’s Hiisipe Incrnerator, Usep at U. S. MakiNnE Camp, Quantico, Va. (Mann) : MopirFicaTion or Mann’s HIisipE IcwvERatoR, Neaeaie: os TO ae ican (Mann) SMALL INCINERATOR OF THE Panauauy Ta FOR Use OF se Sirib wi, 4 AND oe PABLE OF TRANSPORTATION. (Mann) z SrrappDLE Trencu Latrinss, 1 root WIDE, 2 FEET DEEP, 3. FEET LONG, FOR — Operations AT TeMPoraRY Locations. (Mann) s * Coverep Pit Latringe LEVEL with GRouND, A SEMI-PERMANENT Tne " (Man) GarBace Can wit Top ConvertTEeD INTO PortaBLe Urinau ror Us 1n Com- PANY Street at Nicut. (Mann) Se a Urine SoakacE Pit, rn Cross Section. (Mann’s Mopirication rrom LELEAN) Cuart SHowING THE Zones oF Lire Reaction TO TEMPERATURE AND RELATIVE Houmipiry. (Prerce) ae Sab F "i Suecrestep Curves OF THE RESPONSES OF semen Aare roieas TO aa Tre PERATURES. (PIERCE) . ere BD wha . Moura Parts or Fuss: u, suctorial type}. ‘ biting nk: (Gummi) . DiacrRamMMatic SKETCH OF THE House Fiy, Musca domestica. (GREENE) . . ABpominaL Margines or Taree Common House Fuss: a, The house fly, Musca domestica; b, little house fly, Fannia canicularis; c, stable fly, Stomorys cal- citrans (GREENE). In these diagrams the relative size of the abdomen is shown. The light areas in a and b represent yellow markings and are variable in size. In fig.c the markings of the last segment may be present or absent ok CHaracters OF A Muscip Fry Larva. (GrREENE.) Segment 1 is the fiead 2-4 are thoracic segments; 5-11 are abdominal. Segment 11 really contains the seventh to tenth abdominal segments, the spiracles being on the eighth, the anus is the tenth . oe Larva oF THE LITTLE House Fry, Fannia canicularis. Greatly enlarged. Ea waRo AND Pierce, Drawine By BRraDFoRD) i DorsaL View or E1cHtH ABDOMINAL SEGMENT OF THE tue OF Fina canicularis. Very highly magnified. (Drawine BY BraprorD) . Ae 4 VENTRAL VIEW oF TERMINAL SEGMENTS oF Fannia canicularis; the ninth anid tenth segments are comprised in the small zone around the anus. Vent highly magnified. (DRAWING BY BRADFORD) Larva oF Fannia scalaris, THE LaTRINE FLy. rea magnied (Howanp AND Prrrce, Drawine BY BRADFORD) . 08 ; DorsaL View or EicuTH ABDOMINAL SEGMENT OF Fannia seals Very highly magnified. (DRAwING BY BRapFoRD) eta VentraL View or TERMINAL SEGMENTS oF Fannia scalar: “the nineh antl tenth segments are comprised in the small zone around the anus. es highly manera (Drawinec By BRADFORD) . ‘ Larva or Musca domestica: Dorsat VIEW OF coy AND 1 Papenenies ce Larva oF Musca domestica: LaTeraL VIEW OF ‘TERMINAL SEGMENTS. (GREENE) The spiracles are located on the eighth abdominal segment. The ninth and tenth segments are ventral and not very distinct, enclosing the anus Larva or Musca domestica: Enlarged Sketch of Right eee Plate. Thee plates are less than their breadth apart. (GREENE) . Larva or Stomozys calcitrans: Enlarged Sketch of Thoracic Bolenees, (Geman) xxi PAGE 46 46 46 47 47 AT 48 98 102 138 139 140 142 143 143 143 144 144 144 145 145 145 146 XXll LIST OF TEXT FIGURES FIGURE Larva or Stomorys calcitrans: Enlarged Sketch of Right Stigmal Plate. plates are one and one-half times their breadth apart. (GREENE) bn 6 Se Larva or Muscina stabulans: a, Side view of head and prothorax; 6, ciate dite or 24, 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. thoracic spiracles; c, side view of terminal segments of abdomen. (GREENE) : Larva or Muscina stabulans: Enlarged Sketch of Right pay Plate. plates are less than their breadth apart. (GREENE) Larva or Calliphora erythrocephala: Larva or Calliphora erythrocephala: plates are one and one-quarter times their breadth apart. Larva or Chrysomya macellaria: san Sketch of Side of Head and Beitr: (GREENE) .... Larva or Chrysomya renedlone head and thorax; ¢, lateral view of last abdominal segments. A Maccor Trap ror Houserty ContTRoL. concrete basin containing water in which larve are drowned, and the wooden plat- form on which manure is heaped. Use or Frytrap 1n CoNnNECTION Side View of Head aoe pitioits . Enlarged Sketch of Left Stigmal Plate. (GREENE) ‘lynied Sketch of Left Stigmal Plate. plates are less than their breadth apart. (GREENE) . . . Larva or Lucilia sericata: a, dorsal view of head and notices b, laden) view ror (Hutcntson) . ..... with Manure Bin: a, Block of wood set in ground to which lever raising doorishinged. . . ..... Tor or GarBaGE Can wiTH SMALL Batioon Fiyrrap ATTACHED ContcaL Hoop Frytrap; Sipe View: (GREENE) View of the maggot trap, showing the These These (Gxxmna) These "These u, Hoops forming frame at bottom; 8, fies forming frame at top; c, top of trap made of barrel head; d, strips around door; e, door frame; f, screen on door; g, buttons holding door; h, screen on outside of trap; 7, strips on side of trap between hoops; j, tips of these strips projecting to form legs; k, cone; /, united edges of screen forming cone; m, BPeTnre at apex of cone. (BISHOPP) . . ... . Puans or Open Hoc-Ferepinc Troucu. (BisHopp) ..... Fut Grown Larva or THE HuMAN Bor, Dermatobia hominis. ForD.) Actual length 14.5 mm. . Furu Grown Larva or tHe Tumpv-FLy, Condylbia anthropophaga. Ventral view. x6. (From Austen) . . . i ae a Tae Tomepv-FLy, oe sisal (Gnismene) Female. AUSTEN)... ses ee oe (Drawine By Brap- (Grinperc.) x 6. eo Nose PRoTEcTION FOR ere aecainuir ane or THE NosE Fes, Gastrophilus hemorrhoidalis. (DovE) .. . Cuart InuustratTinec THE Lire Cycie or p Telaadlcles columbe, THE CAUSE OF Picron Mauaria. (PIERCE) CuHart IuLustratine THE Lire Cycie or Trypanosoma RUNS THE douse OF GAMBIAN SLEEPING SicKNEss. (PIERCE) .... + pte Larva or A Burrato Guat, Simulium. Eisen eouesoe) Eees or THE Stasie Fy, Stomorys calcitrans ATTACHED TO A StRaw. Gently enlarged. .(Arrer BisHopp) Tue Stasie Fry: Larva or Maageor. Ghintiy enlarged. Chsme on Tue StaBLe Fry: Aputt Fremae, Sipe View, Encorcep witH Buoop. Greatly enlarged. (Arter BisHopp) Lire CycLe or Piasmopium, Cavs Eces or Mararia Mosquitoes: c, A. crucians. (ArTER Howarp, ee £ OF Pernicious Maaria. — Eces anp Larv# or Cutex. Enlarged. (Howarp) . a, Anopheles punctipennis; b, A. es en ee Dyar anp Knap) .... Larva or THE YELLOW-FEeveR Mosquito. Much enlarged. (Howanp) Larva or tHE Mazarta Mosquito, aueplslse punctipennis. Dyar, AND KnaB) . .... Pura or Cutex. Greatly enlarged. Pura or Anopheles quadrimaculatus. fb a a a a a on? (Hows) . Se Gh Te ae). tate Greatly enlarged. (Howanrp) . . . (Arter Howarp, PAGE 146 147 147 148 148 149 149 149 “155 157 160 163 171 187 189 189 205 213 215 225 230 230 230 252 268 268 269 271 272 272 LIST OF TEXT FIGURES XXxiii FIGURE PAGH 54. Pupa or Aedes argenteus, THE YELLOW Frver Mosquiro. salve sees (Arter Howarp, Dyar, anp Knas). ........ Lacan ta nak 272 55. Types or Mosquiro Moura Parts: a, Short palpus aay b, Tong pelpy form (GREENE) ........ A ‘ ‘ . 278 56. Aputt Culex sollicitans. Much witinvedl: (Homann) aye SE 273 57. Tue Yettow Fever Mosquito Aedes argenteus: Aputt Femare. Much enlarged. (Howarp) ....... B tag, Lipa tel pale te Vad de a x we 278) 58. A Matarrat Mosauito, Avonhae sented eteailcbu Mate at Lint AND FEMALE at Ricut. Greatly enlarged. (Howarp) ..... ae j Q7A 59. SUBMERSIBLE AvuTomaTic BussLerR For DistTRiBuTING On. ‘tos ai pacce OF Water. (Epert) . . . . far eer ‘ oe ey > BBE 60. Meruop or PEtTRo.izaTiIon WITH Gu Soicen Since. (Hem) . Bry 28 281 61. Wristtet Merxop Usep ror Breepine Lick. (Hutcuison, Puoro sy Daven) 303 62. Cuart InLusrratTine Tae Lire Crcix or Trypanosoma lewisi. (Prercr). . . . 353 63. Cuart ILLustraTING THE Lire Cycie or THE Doc Tarr Worm, Bi aaoall cani- num. (PIERCE) . ... 2. 1 ee eee 356 64, Larva or THE Evropran. Rat Frixa, Ceratophyllus ‘faschatis. ‘Grewiy enlarged. (BISHOPB)) gcse gp ko a Re ww, RO we 361 65. Tus Doc Fiea, Ctenocephalus canis: a, Egg; 6, larva in cocoon; c, pupa; d, ‘adults e, mouth parts of same from side; f, antenna; g, labium from below. b,c, d, much enlarged; a, e, f, g, more enlarged. (From Howazp) Ry ge Ges ak, 4B eh aoe RR gs Ta MOOS 66. Tae Human Fina, Pulexirritans: Aputt Femate. Greatly enlarged. (Bisnopr) 362 67. Toe Homan Fiea, Pulex irritans: Aputr Mae. Greatly enlarged. (Bisnopp) 363 68. Toe Evrorpean Rat Fiea, Corcaphaina as call Aputt Fermate. Greatly enlarged. (BISHOPP) ..... 64 ee » . 864 69. Tue Sticktigut Fiza, Echidnophaga ene ‘ awaee FEMALE. Greatly en- larged. (BisHopp) . . . . 1. 1 ee eed ea ae 365 70. Heap or Rooster INFESTED WITH THE Gr oniteae Fira, Hehetucphage pitniaeie. Somewhat reduced. (BisHopp) . . ..... coe 2 ao B66 71. Tue Ortentau Roaca, Blatta orientalis: a, Female; 5, ere C cate view of female; : d, half-grown specimen. All natural size.. (Marzarr) Bic PB We el GOT fe se OU 72. Tan German Roaca, Blattella germanica: a, First stage; b, second stage; c, third stage; d, fourth stage; e, adult; f, adult female with egg case; g, egg case, enlarged; h, adult with wings spread. All natural size except g. (From Ritzey). ... 378 73. Tue American Roacu, Periplaneta americana: a, View from above; 6, from ie neath. Enlarged one-third. (Marvatt) ........ ee ee ee 879 74. Beppue: Eaa anp Newry Hartcuep Larva: a, Larva from below; b, larva from above; c, claw; d, egg; e, hair or spine of larva. Greatly enlarged, natural size of larva and egg indicated by hair lines. (Marnuatt) ........ . +. 396 75. Bepsue: a, Larval skin shed at first molt; 6, second larval stage immediately after emerging from a; c, same after first meal, distended with blood. Greatly enlarged. (CMEAREATT) +g. doeice Wap a Sn dh, ee BR es ae ah ee Pete Oe, oh a OG: 76. Bepsuc: Aputt Berore Encorcement. Much enlarged. (Maruatt) . 397 77. Bepsuc, Cimez lectularius: a, Adult female, engorged with blood; b, same from belows c, rudimentary wing pad: d, mouth ae a, b, much hapa ce, d, highly magni- fied. (MaRuaTT) . Bec tea al es. tee . 897 78. CHart oF Lira Creu | oF Babesia cons,’ THE CAUSE OF Conte MAtionanr Tatar pick. (PIERCE) . . 2. 2 6 1 ee ee. ‘ 416 79. Lire Cycie or Hemogregarina canis, THE Cause OF Canine Aneta. " (Pisroe) . . 421 80. Tick Lire Cyciz, Type I. (Arren Nutraty). . ........ . 4 . 423 81. Tick Lire Cyciz, Typz II. (Arrpr Nurratt) ........ 2... . 423 82. Tick Lire Cycrz, Type JI]. (Arrer Nutrart) . . . . . . 1 1 ee ee 485 83. Tick Lire Cyciz, Type IV. (Arrer Nuttatt) ....... 1 2. . . 425 84. Tick Lire Cyciz, Type V. (Arrer NourTary) ........ 2.2. . . 426 85. Tick Lire Cyciz, Types VI. (Prerce) . . es ee oe =, 496 86. Tae Rocky Mountain Sporrep Fever Tick, Dewneunter andirront. (BisHorr) . 437 87. Mopru Curicxen Roost. (Bissoprp) . . Bladen Mee eae een, Ma age AO 88. A CrntipEepE, Scolopendra morsitans. (BRaprorp) . fe erm man aie Panda ces te ty ABS PLATE II. Til. XI. XII. XMI. XIV. LIST OF PLATES Tue House or Typuorw Fry, Musca domestica. Greatly enlarged. (Howarp anp Prercr, Pooto spy Dovenrr). . . . . . . . Frontispiece I. Screw Worms anp Biow Fuss. (Howarp snp Pierce, Puotos sy Dove- NER)! Go. eo ed Hp ge lek es ae GL, Ge cer oes ck Fig. 1. The blue bottle fly, Calliphora vomitoria. ““ 9, The green bottle fly, Lucilia cesar. “* 3. The American screw worm, Chrysomya macellaria. “4. The black blow fly, Phormia regina. Eces or THE American Screw Worm, Chrysomya macellaria, ON Murat. (BisHopp) Riley eh sh . Fires with Dancerous Hasits. (Howarp anp Pierce, Protos sy Dove- NER) a0 si gs a oe ew Oe ee fables Fig. 1. A flesh fly, Sarcophaga sarracenie. “ 2. The non-biting stable fly, Muscina stabulans. “3. The lesser house fly, Fannia canicularis. 4. The brilliant green fly, Pseudopyrellia cornicina. ““ . Screw Worm Insury To a YEARLING CaLr. (BisHoPP) . Manure Box wits Frytrap Artacwep. (BisHopPp) . Manure SprEapDER. (BIsHOPP) . . . Roap Drag In Us ScraPiInc MANURE IN a Cow Lot on A TENNESSEE Farm. (BISHOPP) 3-2 5 See He Ew ee RS He Se . UnpssIRABLE Conpitions Wuicn ARE OvEercoME BY UsE or THE Maccort Trap. A manure pile covering a large area and having little depth. Tllus- trating the conditions which favor the greatest loss of nitrogen, and at the same time offer the best breeding ground for flies. (HurcHIson) . . . . Carcass Partty Destroyep By Larv# or THE AMERICAN ScREW WorM Fry, Chrysomya macellaria. (BisHoprP) Horse Bot Furs. (Dove) ........ Fig. 1. Gastrophilus intestinalis, the common bot. “ 2. Gastrophilus hemorrhoidalis, the nose fly. Puases oF THE Lire Cycie or Bot Fuiies. (BisHopr) Fig. 1. Empty eggs of the cattle bot, Hypoderma lineata. “© 9. Eggs of the common horse bot, Gastrophilus intestinalis. “ 3. Full grown larva of Hypoderma lineata. “ 4, Empty puparium of Hypoderma lineata. “ 5, Empty puparium of Gastrophilus intestinalis. Mernop or Arrack BY THE Common Horse Bot, Gastrophilus intestinalis. (BisHopP) ig, =e. cans sme, Seat =O) eh ay a Fig. 1. Eggs on horse’s legs. “ 9. Larve attached to walls of stomach, showing lesions caused by removed bots in center. : Meruop or Arrack sy THE CaTTLteE Bot, or Heewt Fiy, Hypoderma lineata. (BISHOPP) «© © 6 ee eet ee et ee es Fig. 1. Fly ovipositing on cow’s leg. “9° Portion of cow’s back showing larvee, empty holes, and pus exudate. “ 3. Heavily infested cow. Trenco PREPARED ror Burnine Carcass. (BISHOPP) .- . XXV PAGE 133 134 136 150 155 157 159 159 177 183 184 185 186 201 XXV1 PLATE XV. XVII. XVIII. XTX. XX. XXI. XXII. XXIII. XXIV. XXV. XXVI. XXVII. XXVIII. LIST OF PLATES Pups or Simulium. (ArreR Jopprns-PoMERoy) Fig. 1. Respiratory filaments of pupa of Simulium sittatum. “ec “cc “ec “ Fig. 1. Eggs in straw. 2. Pupz in straw. «“e 8. Adults on leg of cow. 3. Pupa of Simulium bracteatum: 4, Pupa of Simuliwm jenningsi. 5. Pupa of Simulium pictipes, in pupal case. . Tue Srasie Fy, Stomozys calcitrans. 2. Pupa of Simulium venustum, in BuER case. A, Side view of filaments. (BisHopp) All greatly enlarged. Straw Stack SHowinc Proper Meraop or BuriLorne Srraw Srack. (Bis- HOPP) . . Tue Horn Fy, Lyperosia irritans. Fig. 1. Flies on cow, Tapantp# ArrackInGc CatTTLe: punctifer on top of shoulder. (BIsHOPP) 2. Cow pasture showing droppings improperly left to breed flies. Tabanus ia on cow’s jaw, and 7. (BisHopr) . od ee Tabanus punctifer. (WEBB, PHotos By DoveneEr) Fig. 1. Egg masses on grass. 2. Larva, dorsal view. 3. Larva, lateral view. 4, Pupa, lateral view. 5. Pupa, ventral view. “ce ““ “ Tue Cxotrainc Lovuss, Pediculus corporis. Pxotos By DovENER) Fig. 1. Female, ventral view. 2. Male, dorsal view. “ Eecs or THE Cioraine Louse, Pediculus corporis . . Fig. 1. Mass of eggs, slightly reduced, between seams oo trousers (PHoto BY DoveENER.) “ “cc (PHoTo By Patne.) Steam STERILIZER IN leading into the other room where another carriage is seen. Scaty Lec Mite on CBICKENS. “6 (Pierce anpd Forcatson, 2, Great enlargement showing eggs hatching. (PHoto By PaIne.) 3. Very great enlargement showing structure of eggs with exuvie within. Nn Detovusine Station or U. S. Army Mepican Corps. The carriage is transferred along the rails in the foreground to rails (Hutcuison) (BrisHopr) Fig. 1. Scaly feet of chickens, caused by mite attack. 2. Scaly leg mites, greatly enlarged. Drierine Scary Lecs or CHicKEN IN CrupDE Ot. Tue Fowu Tics, Argas persicus. Fig. 1. Larvee under feathers of chicken. 2. Unengorged male, ventral view; much enlarged. 3. Female with eggs, dorsal view; greater enlargement. 4. Unengorged female, ventral view; same enlargement as fig. 2. “e “6 “cc (BisHorp) . Tae Cattie Tick, Boophilus annulatus. Fig. 1. Fully engorged female. “6 Sprayinc CuickeN Hovse witH O11 py Means or Knapsack Spray Pomp. (BisHopp) . (BIsHoPP) 2. Engorged female depositing eggs. (BisHopp) PAGE 227 231 232 233 236 238 302 305 323 406 407 433 435 447 SANITARY ENTOMOLOGY CHAPTER I How Insects Can Carry or Cause Disease ! W. Dwight Pierce Our nation, as well as all our world civilization, is facing the greatest crisis in its existence in these days of reconstruction. We must con- serve human energy and keep it at its greatest possible point of effi- ciency. This means above all that questions of health are foremost today. Entomology bears a twofold relationship to health. Adequate food supply upon which human and animal health are contingent is dependent to a greater or less degree upon insect depredations. This is the side of | entomology which has in the past received most of the recognition, that is, agricultural entomology. It has been generally recognized that insects also bear a direct relationship to health, but the public has more or less discounted the relationship, with the result that our public appropria- tions for the study of insects affecting crops are approximately thirty times as great as the appropriations for the study of insects affecting the health of man and animals. The present course of lectures aims to give the latest views in this almost unworked field of medical entomology, with a view toward demonstrating the necessity of obtaining a better balance in the two great phases of economic entomology. The scope of the course embraces studies of the relationship of insects to disease, the life history of the insects which cause disease, and the best methods of prevention of disease causation by insects. It is intended to be placed in the hands of the men who will conduct work along these lines, to show them why insects are dangerous, how they are dangerous, what their habits disclose as weak points subject to attack, and finally, how to go about controlling them. In my opinion the near future will see a group of professional sanitary entomologists whose services will be available to solve the insect prob- 1This lecture was given on May 20, 1918, and mimeographed copies were dis- tributed May 22. It has been considerably revised for the present course. 19 20 SANITARY ENTOMOLOGY lems of municipalities, communities, and armies, as well as household and ‘commercial problems. Municipal entomology has already been recognized in a small way by certain cities. It will become better known only by the work of entomologists themselves who are men of vision. The prob- lems involved in entomology sanitation demand an intensive and spe- cialized training which few of us received in school. If we would fit ourselves for such work it will demand great effort on our part. CLASSIFICATION OF METHODS BY WHICH INSECTS CAN CARRY OR CAUSE DISEASE Long before any one knew of causative organisms in medicine it was recognized that insects might be productive of disease. We may there- fore assume as our first category the diseases actually caused by the insects themselves. (1.) Diseases caused directly by insects ——We must recognize, for the sake of arrangement, all pathological conditions brought about by insects whether of a serious nature or not. 1. Entomophobia.—The fear of insects, both harmless and harmful, is a common ailment, amounting in many people to an obsession. I know of a young lady who became so frantic over the presence of a huge dragon fly in the automobile that the attempt to catch it led to a serious accident. Recently a serious automobile accident was caused by a bee sting. Many women become frantic at sight of large insects, and I have even seen men lose all sense of courage in the presence of an unknown species of insect. Obviously only patient and tactful educa- tion can ever cure such an obsession. 2. Annoyance and worry.—We have all probably experienced a sense of annoyance, amounting sometimes to worry, from insects. It frequently happens that the annoyance increases to the point of causing acute nervous troubles which, it is quite conceivable, might lead to insanity. with certain people. Animals are frequently driven frantic by insects such as buffalo gnats, mosquitoes, and horse flies, and lose all control of themselves. We may classify these different cases of insect annoyance in accordance with the sense which perceives it and commu- nicates its sensations to the brain. In this manner we have annoyance originating through sight, memory and imagination, sound, smell, taste, and feeling. Sight worry is initiated by the occurrence of unwanted insects in home or garden, or on one’s person, or by their constant swarming about until patience is exhausted and one loses control of the nerves. A recently recorded case tells of a lady whose house was badly infested with book lice and who was fast becoming a nervous wreck when HOW INSECTS CAN CARRY OR CAUSE DISEASE 21 entomological service was sought and the house freed of its pests. The constant moving of streams of ants across a floor, the sight of bedbugs or fleas, and many other common insect occurrences may cause a nervous person great perturbation. Recently a young entomologist was nau- seated and made very sick for hours by the sight of a louse infested man. Memory and imagination worry may be exemplified by the person impressed by anti-house fly propaganda, whose imagination sees on every fly multitudes of fatal disease germs. A person once injured by an insect will often experience acute revulsions of feeling on sight of another similar insect. Sound worry such as that induced by the singing of mosquitoes or the buzzing of horse flies will often lead to insomnia and in the cases of animals will cause great uneasiness. Smell worry or annoyance from insects often takes the form of great embarrassment. A few years ago in Dallas, Texas, Calosoma beetles were so numerous that people walking on the streets frequently would have one alight on them, and, in brushing the beetle off, would cause it to expel a sufficient quantity of liquid to make the person’s presence undesirable in polite society. Many people are so sensitive to bedbug ~ odors that when they sleep in infested rooms they are constantly aware of the odor and are possessed of a fear that they will be attacked by the bugs. Taste annoyance is often caused by eating berries containing bugs, or which bugs or cockroaches have contaminated. This may often cause nausea. Finally, there is the worry aroused by contact of insects, the tingling sensation from insects crawling on the body, the peppery sting of gnats and mosquitoes, the itching sensations from vermin. Insomnia is a frequent result of such attacks. Thus as results of insect annoyance, we may have worry, nervous exhaustion, excitability, hallucinations, frenzy, insanity, nausea, insomnia and nervous chills. 3. Accidental injury to sense organs.—There are numerous cases on record of insects accidentally obtaining access to the ear or nose and causing a stoppage of these organs, or of insects flying into the eyes causing severe irritation or even blindness. Certain “species of gnats are especially annoying when there is any kind of catarrhal affection of these organs. Myriapods have frequently been recorded as entering the nose of a sleeping person. 4. Poisoning.—Insects and the related arthropods may poison in a variety of ways. The bite of a tick, flea, spider, mosquito, horse fly, etc., may cause a severe local irritation and poisoning. The poisonous 22 SANITARY ENTOMOLOGY centipedes have a poison sac opening on the front pair of legs. The scorpion stings with the tip of its tail. The bee, wasp, and ant sting with the ovipositor. Many of these injuries are very painful. Certain lepidopterous larve are provided with barbed hairs which contain poisonous secretions, as the brown tail moth larva, and the larve of Lagoa, Hyperchiria io, etc. Some insects emit poisonous secretions which blister (Meloid beetles). Some of the South American honey bees (Trigona) store poisonous honey. 5. Paralysis—The bite of several species of ticks (Dermacentor andersoni (venustus), for example, may cause paralysis with sometimes fatal results. Some spiders, ants, bees, wasps, and caterpillars inflict such a poisonous wound that temporary paralysis of the limb follows. 6. Dermatosis.—Direct attack upon the body of men and animals, and parasitism thereon, is not unusual. We have as striking examples the dermatoses caused by lice (pediculosis), by the chigoe, the red bug (chiggers), the Dermatobia hominis, creeping worms, scab and itch mites (acariasis). Many of these attacks have serious after results, as for instance an acute attack by the chigoe may result in ainhum, the loss of a toe or a foot. Many secondary diseases obtain access to the * body through the skin attack of insects. 7. Mytasis and similar internal attacks—Under this heading are to be considered cases in which insects are present in the tissues of internal organs of the body. The occurrence of insects has been recorded in organs of the head, in the intestinal canal, the reproductive organs, and the body wall. When the insect is a fly the disease is called Myiasis. When a beetle is the cause, the disease is called Canthariasis, and if a lepidopterous larva is responsible it is known as Scholeciasis. Many species of flies have been recorded as occurring in the human body. These will be studied in detail in a later lesson. (II.) Diseases carried by insects —The ways in which insects may carry diseases are very diverse, due to the great differences not only in the habits of the insects, but also of the disease organisms and the hosts. 1. Diseases carried by insects to food—When insects carry disease germs to food or water we speak of the transmission as contaminative. Contaminative transmission of disease organisms to food by insects is naturally the simplest manner of transmission. This is necessarily done by insects which frequent excretionary substances and also visit foods, such as certain flies, ants, roaches, and beetles. It is obvious that we must look upon all insects which breed in fecal matter, sputum, etc., as potential disease carriers. Considerable research has already been con- ducted to prove the actual réle of many species of coprophagous insects. The réle of the carrier may either be mechanical or biological. HOW INSECTS CAN CARRY OR CAUSE DISEASE 23 Many disease organisms are transmitted by insects which exercise apparently only a mechanical réle. Principal among these are bacteria and certain parasitic worms. Many of the bacteria may be taken up by fly and beetle larvae, and by adult flies, beetles, roaches, and ants, and be carried on the body or ingested and passed through the body and out in the feces without modification or multiplication. A number of species of parasitic worms may be taken up in the egg stage by insects and deposited in the insect’s feces. If such infested feces happen to be deposited on food, contamination and infection may conceivably follow. Certain other organisms which are carried by insects to food pass part of their life history in the insects. Such are some of the nematodes that may be ingested by coprophagous insects, which in turn are eaten by the animals that serve as final hosts of the parasites. 2. Diseases carried by insects to wownds.—We can make the same division of these diseases into mechanical and biological carriage. The transmission of anthrax, leprosy, ophthalmia, and such diseases, from sore to sore or from excreta to sore is purely mechanical. When the organism passes part of its life cycle in the insect we might call the transmission biological. As examples of such types of transmission we may cite European relapsing fever and trench fever, louse-borne diseases which gain access to the body by the scratching in of fragments of the lice or their excreta. 3. Diseases gaining access through direct attack of insect—Most of the protozoal diseases and some of the parasitic worms gain access to the body of the vertebrate host by direct inoculation, or indirectly, at the time of feeding. When the organism is taken up by the insect it begins its development in the insect body and finally reappears in the salivary glands or some other position adjoiming the mouth parts, the inoculation occurring during the blood feast. Such is the inoculation of malaria, .yellow fever, and Rocky Mountain spotted fever. But other disease organisms pass through the intestinal canal of the insect and out in the feces and yet obtain access to the wound by being washed into it by body secretions of the insect, as is the case of the organism of African relapsing fever inoculated by the tick Ornithodoros moubata. WHY IT IS NECESSARY TO KNOW HOW INSECTS CARRY DISEASE In the foregoing discussion I-have attempted to analyze the methods by which insects can cause or carry disease. There is also a practical side of the question. We must know the why and the wherefore and the what to do. Without a conception of the réle of the insect we cannot give suf- ficient force to our arguments, or reasons for taking a particular course 24 SANITARY ENTOMOLOGY of action. For instance, if we were merely to go before the inhabitants of a Montana valley suffering from Rocky Mountain spotted fever and say: “We are going to put down this epidemic, you must dip your horses and trap all the rabbits and rodents on your plavs.” \what kind of an answer would we get? If the Public Health Servic: had stepped into New Orleans on the announcement of a plague case and ordered every- body to rat-proof their cellars, without further reason, they would have been driven away. If a sanitary officer reports to his superior that a certain thing must be done, requiring a considerable outlay of money and the use of a good many men, he must be able to give him a strong, forceful argu- ment to prove that he is right. Army officers, and in fact most executive officers, want brief answers. The subordinate must therefore have his information on the tip of his tongue. We have seen by the above discussion that the bites of insects must be avoided. Where disease-carrying insects are present, the greater the concentration of human beings or animals, the greater the necessity of exercising control, whether it be in a municipality, a commercial estab lishment, an army, a stock yards, or a ranch. It is incumbent upon all men charged with entomological sanitation to learn the bloodsucking fauna about them. Without a knowledge of how mosquitoes, horse flies, bedbugs, lice, stable flies, gnats, and ticks breed, one can scarcely proceed to prevent their breeding and consequently cannot protect men and animals from their attacks. One must always prevent insects from coming in contact with wounds. This is especially important in hospitals and during times of epidemics. It is at all times imperative to keep food untouched by anything in the form of insect life. Insects must not be tolerated in dwellings, no matter whether there is evidence against them or not. There is evidence against most of them. Domestic animals must likewise be kept as free as possible from insects. Some day we will recognize that stables should be as well proofed against flies as dwellings are now. There are more inducements for flies and other noxious insects around a stable than anywhere else, and the stable is therefore the direct or indirect source of many of our troubles. The measures necessary for holding down insect infestation of stable and barn yards are therefore of primary importance. But to emphasize this importance there must be back of every measure taken or recommended an argument in the form of a proof of danger if the measure is not carried out. CHAPTER II Some Nécessa steps in Any Attempt to Prove Insect Transmission or Causation of Disease 1 W. Dwight Pierce The study of the causation of disease is attracting far more attention today than it ever has in the past, but it is to be regretted that there is not a larger proportion of this effort being directed toward locating the possible intermediate hosts and invertebrate carriers. Many excellent investigations have been carried out with all other phases complete, but the question of invertebrate carriers is often left in a very indeterminate stage. The majority of the investigations which have been seriously undertaken to determine invertebrate carriers have been conducted on other continents than ours. There is a great field for investigation along these lines open to the investigators in America. In order to stimulate such research, I have attempted in this paper to set down some of the necessary steps for successful investigation. 1 I. COOPERATION I consider essential to a thorough, investigation of disease trans- mission, the establishment of a perfect working agreement and hearty cooperation between one or more physicians and diagnosticians, one or more parasitologists, and one or more entomologists. It is not safe, nor does the effort bring the proper amount of credence, when one man attempts to do the whole work. Each phase of such an investigation should be handled by an expert on that phase. The day of the solitary investigator is past and we are now in an era of group-investigations. which carry with them weight and conviction. Of course certain pre- liminary steps may easily be taken by any one member of a proposed group or it may be possible that they may arrive at an advanced stage by independent work, but the time will come in each investigation’ when a cooperation of investigators will attain the most satisfactory results. 1This lecture was printed in Science, n. s. vol. 50, No. 1284, pp. 125-130, August 8, 1919. 25 26 SANITARY ENTOMOLOGY Il. WHERE SHOULD THE INVESTIGATIONS OF INSECT TRANSMISSION BEGIN? There are two distinct lines of approach to this problem of insect transmission. The first is to work from the known disease and to ascer- tain by experimentation what species of insects might be concerned in its transmission. The other line of approach is to make a study of all the insects which might be involved in disease transmission and to obtain, by cultures and microscopic studies, a knowledge of the parasitic organ- isms normally and occasionally found in these insects. Working on this line of investigation, one might in time of an epidemic start with insects visiting excreta and attempt to ascertain whether the organism of the disease at that time epidemic occurs in any of these insects. The first line of investigations would arise from public necessity and probably be initiated by physicians and parasitologists, or by the sugges- tion of entomologists. The second line of investigations would probably originate as problems assigned by a professor or head of a laboratory to students or investiga- tors under his direction. It is highly desirable that such studies be com- menced in as many institutions as practicable in the near future. Such investigations will include bacteriological studies, protozoological studies, and helminthological studies, as well as investigations of the life histories of the insects, and the possible connection between them and disease transmission. Ill, PLAN OF OPERATION Before starting out on any line of experiment in this subject, there should be written down in concise form the facts already gleaned, on the practical problems and the theories which have occurred to the various members of the group. A clearly outlined course of action should be made and be carefully discussed and then the various steps in the inves- tigations thus outlined should be read and modified to meet the changing views resulting from the experiments. The course of the work should always be kept plainly in view. Each step should be rigorously and skeptically scrutinized for defects. Inasmuch as the investigation from this point will consist of the answering by observation and experiment of a series of pointed ques- tions, I shall proceed with my discussion in the form of queries. Prob- ably many other vital queries will occur to the reader, but it is more than possible that he may overlook some of these if not set forth here. When each query is satisfactorily answered the problem is practically solved. STEPS TO PROVE INSECT CAUSATION OF DISEASE 27 Iv. HOW SHALL WE RECORD OUR OBSERVATIONS? Undoubtedly the most satisfactory method of making a large series of records is to use some type of loose-leaf card or sheet filing system. By such means one can always keep in an orderly arrangement all the facts so far obtained. In the case of investigations of the causation of a given disease, one of the most satisfactory methods which has been used for recording observations is to prepare a little blank booklet, which will fit the filing system, in large quantities, each book to represent a case. This book should contain pages for each phase of the question, with blanks covering all kinds of minutia about this phase. The whole series of observations can be tabulated for each point. Vv. HOW CAN AN INSECT BE INVOLVED IN DISEASE TRANSMISSION? Insects may be involved in disease transmission either by the trans- mission of an organism or the inoculation of a toxin, or they may be an intermediate host in the life cycle of an organism, but not come directly in contact with the final host. 1. What Kind of Organisms Can Insects Carry? It has been demonstrated that insects can carry bacteria, fungi, many types of protozoa, and many species of parasitic worms, and also that certain species of insects may be instrumental in carrying eggs of other species of insects which cause disease. 2. In What Manner May Insect Toxins Bring About Disease? Many species of insects which bite inoculate at the time of the bite a toxin which may at times cause serious trouble. Some invertebrates inoculate the toxin by means of the mouth, some by means of a claw, some by means of a caudal appendage, others by means of the ovipositor. In some cases the invertebrate penetrates the skin with its mouth parts and as long as it is adhering, toxins are created which may in certain cases cause severe paralysis or death. The acci- dental eating of certain insects in food will cause poisoning because of the toxins contained in the bodies of the insects. It is believed, but not yet satisfactorily demonstrated, that the pollution of food by the excreta of certain insects may cause certain nutritional diseases. The presence of certain insects in the tissues causes severe irritations and often the formation of toxins. 28 SANITARY ENTOMOLOGY 3. Can Insects Themselves Cause Disease? Many species of insects are known to live parasitically upon the bodies of man and animals and by their constant sucking of blood or gnawing, cause skin diseases. Other species of insects habitually lay their eggs on or in the flesh and breed commonly or exclusively in living flesh, causing a destruction of the tissues. Many species of insects are depen- dent upon mammalian blood for the necessary nutriment to bring about reproduction. Some insect larvae are bloodsuckers. It is not at all uncommon for insect larvae to be ingested in food and for them to con- tinue their development in the intestines or other organs, often at the expense of the tissues. In some parts of the world insects are eaten as food by the natives, sometimes in a raw state, and it is not uncommon in such case for the natives to be infected with parasitic worms which pass their intermediate stages in the bodies of these insects. 4, Where May Insects Obtain the Organisms which Cause Disease? Disease organisms may be taken up by insects directly from the blood of an infected host, or they may be obtained by contact with infected surfaces of the body or taken up from the feces or other excretions of an infected host. The insect may take up the organisms from these excretions either in its larval or its adult stage. 5. How Can the Insect Transmit the Organism? The organism may be transmitted by the insect by direct inoculation through the proboscis, involving the active movement of the parasite, or the passive transmission of the parasite in the reflex action which takes place in the sucking of blood. The organism may be externally carried on the beak of the insect and mechanically transmitted at the time of sucking. It may be located in the mouth parts of the insect and burrow through at the same time the insect is feeding. It may be in a passive state on the insect and become stimulated to attack the host when it comes in contact with the warm body. The organism may be regurgitated - by the insect on the body of its host and obtain entrance by its own activity, or by being scratched in or by being licked up by the host. On the other hand, the organism may pass through the insect, and pass out in its feces, or in Malpighian excretions. It may be washed into the wound made by the sucking of the insect, by fluids excreted at the time of the feeding. It may remain in the feces on the host and ultimately be scratched in or licked up by the host. The organism may be taken up by the insect and never normally pass out of the insect, but be inoculated by the crushing of its invertebrate STEPS TO PROVE INSECT CAUSATION OF DISEASE 29 host upon the body, and the scratching of infected portions of the insect’s body into the blood; or may be transmitted only by the ingestion of the insect itself by its vertebrate host, or accidentally by some grazing animal. In fact quite a series of disease organisms find their way into their hosts because of the habit of the animals of feeding upon insects. 6. What Is the Course of the Organism in the Insect? If the organism is taken up by the insect in its larval stage, it may pass directly through the larva and out in its feces and may quite con- ceivably pass in this manner through insect after insect larva before it finally finds a vertebrate host. The organism may be taken up by the larva and remain dormant in some portion of the larva’s anatomy, or on the other hand, it might undergo considerable development and multipli- cation in the larva and remain there through all the metamorphosis of the insect until the latter arrives at maturity, at which time development of the organism may begin or may continue. Upon being taken up in the blood by the bite of the insect, the organ- ism may lodge in the esophagus and carry out all its metamorphosis there, or in some of the organs of the head and find its way into the salivary glands and through the salivary secretions into a new host. It may, on the other hand, pass back into the gut, or into the stomach; from the stomach its path may lead in many directions. It may pass on in its course of development into the rectum and out in the feces, or it may enter the fatty bodies, or pass into the general cavity of the insect, or it may migrate forward into the esophagus and into the labrum; and it may pass into the Malpighian tubules, or into the ovaries. The organism may enter the eggs and remain therein through their development into the larvae, nymphs or adults, and be transmitted at some stage of the development of the second generation. Some diseases can pass on even to the third generation. %. What Is the Course of the Organism on Leaving the Insect? The organism may leave the insect in the saliva and immediately enter the feeding puncture. It may bore through the labium of the insect at the time of feeding and enter the puncture. It may leave the rectum of the insect, or the Malpighian glands and be washed into the puncture by means of the secretions of the coxal glands, or some other: excretions made at the time of feeding. It may be excreted in Malpighian secre- tions, or rectal feces, or regurgitated in vomit, and may lie dormant on the skin of the host, or on the food of the host, until it is scratched into the blood, or is taken into the mouth. 30 SANITARY ENTOMOLOGY On the other hand, it may be possible that the organism requires another host after the insect, and before it reaches its final host. There are cases on record of the insect being the first host, and two or three vertebrates in succession being hosts of later stages. VI. WHAT IS KNOWN ABOUT THE DISEASE TO BE INVESTIGATED ? It is a primary essential that all the workers be able to recognize the disease which they are trying to study and that they be fully informed about it, so that they may be able to grasp possible solutions of their problem. They will, therefore, seek first to answer the following ques- tions: 1. What is the history of the disease and how long has it been known? How serious has it been? 2. What is its distribution? 3. Does it occur in pandemic, epidemic, endemic or sporadic form? 4. In what seasons of the year is it most prevalent? 5. Is there any apparent relationship between its distribution and the physical, biological or climatic features of the countries where it occurs? 6. Does it affect any particular group, occupation, sex, age, race or nation of people, or any particular species of animal? %. May any wild animal be considered as a reservoir? 8. Has immunity or difference of susceptibility been recognized and under what circumstances? 9. What are the symptoms of the disease? 10. What is known regarding immuno-chemistry and bacteriology of the disease? 11. What have autopsies shown? 12. What treatment has been designated? 13. What is known or suspected about its causation and dissemina- tion? What organisms have been connected with it? 14, What possible theories can be advanced to account for its causation and dissemination? A little time spent in collecting these facts may save much effort later. VI. WHAT INSECTS SHOULD BE INVESTIGATED? A thorough entomological study of this question may prove a valuable short cut to the investigation. Many insects will be eliminated by the entomologist before he has finished his preliminary work. He will attempt to answer the following and many other questions and will probably have to answer them to the satisfaction of all his fellow workers. STEPS TO PROVE INSECT CAUSATION OF DISEASE 31 1. What insects coincide in distribution with the general distribution of the disease? 2. What insects occur in peculiar habitats of the disease? 3. What bloodsucking insects occur in the locality under investi- gation? 4, What is the relative abundance of these insects? 5. Is there a coincidence between the season of abundance of any of these insects and of the disease? 6. What insects occur in the homes, nests, or haunts of infected hosts? 4%. What insects are found on infected hosts? 8. What insects occur in the working quarters of the patients? 9. What insects would be most apt to affect the particular group of hosts most susceptible? 10. What insects breed in or frequent the excreta of the hosts? 11. What insects are found at the food of the hosts? 12. What insects are found at the sources of the food of the hosts, such as the milk? VIII. WHAT IS NECESSARY IN THE TRANSMISSION EXPERIMENTS? The investigations which have preceded will have narrowed the ques- tion down to certain species or groups of insects which need to be critically studied. All of those insects which come in contact with the blood or mucous membranes of the patient, or the food of the patient, or the feces of the patient, must be given special attention. At this point the bacteriologist, protozoologist, or the helminthologist finds his special work beginning. There will be many points which must be worked out by cooperation of the parasitologist and entomologist. Considering first the bloodsucking insects, it is necessary to deter- mine: 1. Can the particular insect take up the organism with the blood? 2. Does the organism pass into the intestinal canal or does it stop at some point en route? 3. To what extent is the organism digested by the insect? 4. In what organs of the insect can the parasite be demonstrated from day to day? 5. Are any changes in the organism demonstrable? 6. What path does the organism seem to follow in the insect’s body from day to day? %. Does this movement of the organism suggest whether the trans- mission is by inoculation or does it suggest that the organism will pass out of the body in some of the excreta? 32 SANITARY ENTOMOLOGY 8. Can the organism be demonstrated in the mouth parts of the insect at the time of feeding? 9. Can the organism be found in any of the excretions of the insect ? 10. How long is it before the organism reaches the mouth or the rectum? 11. What is the earliest date at which it can be found in the feces? 12. What is the earliest date at which infectivity of the host can be obtained by the sucking of the blood? 13. What is the earliest date at which infectivity can be obtained by scratching in of the feces or portions of the insect? 14. Can infection be obtained by either natural or artificial inocula- tion without demonstration of the organism? 15. Is the infective organism,, contagium or virus filterable? 16. Can the virus or organism be transmitted hereditarily by the insect ? 17. At what stage of development in the second generation does hereditary transmission become possible? 18. Can the organism be taken up by the immature stages, feeding in infected excreta? 19. Can the organism be taken up by immature stages of an inverte- brate feeding on the host? 20. How long can the immature forms of the invertebrate, infected by whatsoever manner, retain the organism in their system? 21. Does the organism stay in the insect during metamorphosis? 22. Does the organism undergo any changes preceding or following metamorphosis of its invertebrate host? 23. At what stage in the metamorphosis does the insect begin to be infective after taking up such organisms? 24, How long can the insect remain infected and infective? IX. HOw SHOULD EXPERIMENTAL INSECTS BE HANDLED? A large proportion of the failures in studies of insect transmission in the past have arisen from improper handling of the insects. The breeding and handling of the insects is an art in itself, just as is the culturing of bacteria or protozoa. In fact, there are more diverse requirements for handling insects of different species than can be found elsewhere in the animal kingdom. 1. What must be known about the insect before beginning trans- mission experiments? The normal conditions of life of the insect must be ascertained :—its STEPS TO PROVE INSECT CAUSATION OF DISEASE 33 reactions to heat and cold, moisture and dryness, disturbances, color, light, odor; its food, and the proper condition thereof; its methods of reproduction, and what food is necessary for reproduction; if soil should be provided, and what conditions it should be in; if water should be provided, and whether this water should be alkaline or acid, clear or containing foreign matter, and in such case what type of foreign matter; whether the water should be still or in motion, warm, moderate or cold. 2. What type of breeding cage should be used? A breeding cage must be used which will most nearly enable the experimenter to keep the insects under control and yet reproduce essen- tial conditions for maintaining normal, healthy life of the insects and normal reproduction. Much of this information is available in entomo- logical literature. Many insects probably involved in disease transmis- sion have not been properly studied and breeding technique is yet to be worked out. 3. Water is necessary in some form in practically all insect breed- ing. ° There are more failures to properly breed insects traceable to im- proper humidity, or to the lack of moisture in the proper form for the insects to drink. Much detailed observation may be necessary to obtain this important information in the case of many insects. 4. There is a combination of temperature and humidity most favor- able for life, for each species, and differing from one species to another. 5. The food of an insect must be in a particular condition in order to obtain normal breeding. It may require a certain degree of immaturity, ripeness, or fermentation. It may require a certain degree of desicca- tion. Many other details must be attended to by each specialist involved in the investigation, and we probably have yet to see a single disease problem which has been completely rounded out and solved for the future generations. CHAPTER ITI A General Survey of the Needs of Entomological Sanitation in America + W. Dwight Pierce Notwithstanding the great amount of publicity which has been given the Anti-fly Campaign, one will find throughout our land a rather general disregard of the danger from flies. Certain newspapers keep the subject annually before their readers, but on the whole, public co- operation is slight. A few cities and communities have definitely organ- ized mosquito control work, and the Public Health Service has done a wonderful amount of work in organizing such efforts. From an ento- mological standpoint our nation is not sanitary. The reason lies in the fact that the public does not yet realize that insects can and do carry disease. Science has apparently not put forward the idea in such a manner that it has gripped the average person. Until we do this we cannot expect public cooperation in the attempt to put down insect- spread diseases, The problems we have to meet may be divided in several different manners. We may separate them into problems of municipalities, towns and villages, and rural communities. We may look at them from the standpoint of the farm, the home, the market, the factory, and the institution. They may be sorted out as problems of drainage, waste disposal, screening, animal control, etc. Of course we have a greater diversity of entomological contro: prob- lems in a municipality, but we also have more people who give attention to matters of health in a city, and who would complain against un- healthful conditions. On the other hand, while the problems of the rural community and town are fewer, the insect conditions often become greatly aggravated because of total carelessness as to sanitation. This careless- ness in small towns and farms is usually due either to ignorance or lack of organized effort for community betterment. The field of the sanitary entomologist who desires to tread virgin soil is therefore to solve the ways and means of obtaining better fly and mosquito conditions in rural communities. Educational work must be *This lecture was mimeographed and circulated to the class in January and ap- peared in parts in The American City, for February and March, 1919. 34 NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 35 carried out which will be of such nature that it will bring results. We have the theories and the scientific facts but we must give the public practical] demonstrations that freedom from insect pests means reduced sickness. Any person informed on this subject who has traveled much in rural sections of this country and seen the unobstructed entrance of myriads of house-flies to the dwellings, especially the kitchens and dining rooms, and then has stepped outside and within a few feet found the open privies breeding these flies, cannot help but feel a sickening sensation and a revulsion toward eating anything that the flies could have polluted. It is not at all uncommon in rural sections to see babies exposed to the unre- stricted visits of flies, and their milk bottles covered with them. The writer has been informed over and over by physicians in small towns that when infantile diarrhea or any other intestinal complaint visits a “ town it makes the rounds of every infant in the town, unless perchance, some mother is more advanced in her knowledge of such matters and keeps her baby constantly screened. When typhoid fever and dysentery visit towns with open privies and unscreened houses or hotels only the more cautious and more resistant escape. Such communities offer every conceivable opportunity for the spread of diseases by flies. THE INSANITARY FARM For fifteen years the writer has traveled extensively in rural communi- ties, principally in the Southern States, where insanitary methods, if existent, aggravate disease conditions because of the more favorable climate and greater number of maladies present. We may picture, there- fore, a few of the conditions which have been repeatedly seen in these travels, in order the better to show the problems to be met. We shall not claim that these pictures represent the predominant, or the usual, or the average condition. Let it suffice that they exist sufficiently often to make them worthy of serious attention. The farm we will describe has been seen countless times. The house has no screens on the windows, in fact, often has no window panes, or may have wooden windows which are open all day. The house is one~ storied with an outside chimney, and an open fireplace. The chimney and fireplace offer excellent day hiding places for mosquitoes, which are abundant if there is a slough or bayou nearby. The house is built on stumps or pillars raised above the ground. The pigs and chickens, dogs and cats, wander freely underneath. The house has a great open hall- way through the middle, separating the bedrooms from the living rooms. On account of the numerous flea-breeding animals which pass under the house, fleas are not at all uncommon in the house. The well is usually 36 SANITARY ENTOMOLOGY open and built into the back portion of the porch. Mosquitoes breed in it. There is a poorly constructed, dilapidated privy for the women not far from the house, but the men have none, or if they do, it is not fit to enter. They usually defecate in the open, in the fields or draws, or in a woodland patch. The barn is roughly constructed. The manure is piled in a great pile beside the barn, and breeds multitudes of flies. The stable floor is urine- and manure-soaked and affords excellent fly-breeding quarters. Naturally, I have described the worst common type of farm, because on this must be built the structure for better sanitation in farm life. In many cases a large number of such places may exist on a single large plantation, for the use of the tenants. In such cases a single man is responsible, who himself lives in a house with all modern sanitary conveniences. The problem of the sanitarian and the sanitary entomologist is to prove to the individual farmer and to the planter landlord the financial value of better sanitation. The planter must be shown that inasmuch as the efficiency hours of his tenants are increased, in proportion will their products be increased, and in like manner his rental, especially where the rental is based on certain proportions of the crop yield. He must see that reduction of mosquitoes means reduction of malaria inci- dence, that reduction of flies reduces the incidence of typhoid, dysentery, diarrhea, and other intestinal complaints, and that as the sickness rate on the plantation is decreased the labor output is increased. It will do us no good to theorize if we do not set down clearly the ways and means of accomplishing this greater farm output by reducing fly and mosquito breeding. In the present course of lectures will be found the proofs which have accumulated against these various insects, brief statements of how these insects live, and detailed plans of the approved methods of control. Fortified with this ammunition and more which he will personally gain, the sanitary entomologist must fight for better sanitation. HOW TO IMPROVE FARM SANITATION At this time, however, we may in brief state a few measures which should be taken on every farm in order to accomplish greater farm labor efficiency and improve the health of the household and of the animals. 1. The windows and doors should be screened against flies and mosquitoes. During the months that fires are not used the chimneys should have a screen over the top and the fireplace screened. If wire screening cannot be afforded, mosquito bars can be used. In the majority of cases the expenditure of the necessary amount of money to properly NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 37 screen the place will be offset by a greater reduction in doctor’s bills for the women and children at least. 2. Where there are many children passing in and out flies will get in. The children should be taught to use fly swatters. No flies should ever be allowed to remain in the kitchen and dining rooms. Flies which visit food will deposit on it any disease organisms they have picked up. If the water is pure, the fly is about the only common means of conveying intestinal diseases to the family. 3. Unless the babies and small children are kept indoors in screened rooms, the helpless children should have a mosquito bar over the carriage or basket so as to protect them from flies. This is absolutely essential if there is any sickness in the neighborhood. 4. There should be installed sanitary pit or bucket privies such as are recommended by the Public Health Service. Both men and women should be provided with such, and it should be aerule of every farm that indiscriminate defecation is absolutely forbidden. As many farms are quite large the most feasible plan would be to place at various places over the farm where they would be most convenient and best protected, some type of latrine, such as is used by armies, or better still a perma- nent privy. 5. The well should be kept covered to prevent as far as possible mosquito breeding and contamination. 6. The foundations of the house should be boarded up to prevent the access of animals and to eliminate a favorite mosquito hiding place. The ground around the house should be so drained that water will not flow under the house except in case of*heavy rains, and in such cases will quickly drain off from under the house. 4%. All ditches, ponds, streams, and bayous on the farm should have the banks kept clear of obstructions to the free flow of the water. There should not be any tree stumps, trees, roots, weeds, or logs in the stream. The banks should not have overhanging ledges, or puddle pits. Per- manent ponds and lakes might be stocked with mosquito-eating fish. Places which habitually form puddles after rains should be filled and drained. 8. The barns should have hard packed dirt floors or cement floors. All manure should be removed daily from the barn. If possible the manure.should be spread while fresh on fields lying fallow. Otherwise the manure should be piled in tightly packed stacks or on platforms over a cement basin containing water, in order to drown the fly larvae migrating for pupation. 9. The garbage should be fed to pigs, preferably in sanitary feeding stalls as described by Bishopp in the lecture on the control of flies in barn yards, pig pens and chicken yards (Chapter XI). 38 SANITARY ENTOMOLOGY 10. State Boards of Health should follow the California plan and forbid the marketing of fruit dried on farms with open sewage, or where exposed to visits of flies, THE INSANITARY TOWN In these same travels in which so many insanitary farms were seen, the writer has sojourned in or passed through many towns which might be described as follows: The streets are unpaved and are littered from one end to the other with papers, cans, and the accumulation of months of manure droppings, and are altogether filthy and unattractive. The removal of trash is nobody’s business. The grocery stores and meat markets are unscreened and have open doors. The food is covered with flies. Farmers drive up and buy a side of salt pork or other meat, throw it into the pit of their wagon, uncovered, and drive down the dusty road, with a swarm of flies hovering over the meat. The small lunch rooms where the visiting farmer eats his noon or evening repast are dirty and full of flies. The stores have privies in the rear which are filthy and an offense to any decent person. Flies abound. Chickens and pigs wander unrestricted through the streets and are often found feeding under the privies. The hotel dining rooms and kitchens are always full of flies and are usually but a short distance from filthy privies, and flies are constantly passing back and forth. Cockroaches are served in the food and wander unrestricted everywhere. The bedding is often unclean and has been slept in by some one else. Bedbugs are not uncommon. The water pitchers contain mosquito wrigglers. The cis- terns behind each house are unscreened, and contain rain water, full of mosquitoes. The livery stable has great piles of manure in the stable yards and sometimes right out on the sidewalk. Sometimes the town is a little bigger and the people have become more civilized and installed interior plumbing, which empties the sewage into a ditch which runs down to a stream from which cattle drink, or quite ‘ often this sewage empties into the gutter on the street and fills the air with filthy odors. Such is not an uncommon thing in America. Only a few years ago we could have pointed out quite a number of cities in the 100,000 class with open sewage. These small towns are often rat infested, and one can easily see the danger should an outbreak of plague, which is transmitted by the rat flea, get a start in such a town, by the advent of a plague infested rat. HOW TO IMPROVE SANITATION 1. Organize the community for better sanitation, and call in an expert of the Public Health Service, which is giving a great deal of NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 89 attention to cooperative health work. In Russia, such organizations were springing up all over the land before that country became submerged in its present chaos. 2. Conduct a health publicity campaign. 3. Teach better sanitation in the schools and organize the children for clean-up work. 4. Require the screening of all stores selling food, and of all hotels and restaurants dispensing food. Do not allow food to be handled in such a way that it will attract great quantities of flies. 5. Require private stables to place manure in fly-tight boxes and to have same removed every 7 to 10 days. 6. Require livery stables to remove all accumulations of manure daily from the town limits. 7. Require the burning, feeding or removal of all garbage twice a week from homes and daily from hotels. 8. If garbage is hauled away and dumped the town should arrange for its daily incineration. 9. Require throughout the town limits, depending upon conditions, either sanitary plumbing and sewer connection, or sanitary box or pail privies. Do not allow pit privies or insanitary ones of any type. Do away as soon as possible with open sewer drainage, installing sewer pipe. Install sewage septic tanks of size adequate for the town. If there are no sewers laid it may be possible to arrange for individual installation of simple septic tanks. 10. Do not allow pigs and chickens to have access to privies. 11. Do not permit general roving of pigs, stock, chickens, etc., on the town streets. 12. Keep all ditches and waterways in the town free of obstruction, and if mosquitoes are breeding, have an oiling squad. 13. Fix strict penalties against defecation on streets, alleys, and vacant lots. ; 14. Install a town comfort station for strangers and people from the country. SANITARY PROBLEMS OF CITIES The sanitary entomological problems are multiple in large cities, and such that it would be an excellent practice to employ at least a consult- ing entomologist in all large cities. As a matter of fact many cities should have quite a corps of practical sanitary entomologists engaged primarily for this type of work. City markets where meats, fish and all kinds of vegetables and produce are exposed for sale, are very attractive places for flies, and in many large cities there is gross neglect along these lines. 40 SANITARY ENTOMOLOGY Sanitary inspectors need to exercise considerable vigilance in checking up obedience to ordinances relating to removal of trash, garbage, manure, excreta; installation of sewage or sanitary privies; proper sanitation among construction gangs; nuisances arising from stables, factories, sewage and garbage disposal plants, packing houses, stock yards, etc. Many manufacturing plants have waste products which are very attrac- tive to insects. Insect conditions in restaurants, boarding houses and hotels should be frequently checked up. Anti-fly and anti-mosquito propaganda should be conducted annually in every city until the people are so well educated to the necessity thereof that propaganda will no longer be necessary. The sanitary department of large cities should directly supervise mosquito suppression within its bounds. ENTOMOLOGICAL REQUIREMENTS OF MUNICIPAL SANITATION The following points should be covered by ordinance in all large cities desirous of obtaining satisfactory sanitation. Not enough attention has been given by city health authorities to the insect side of their sanitary problems. 1. All foodstuffs, which are eaten raw, all raw meats, fish, birds, cooked foods, bread, cheese, dried fruits, etc., must be kept under cover of glass or screen or otherwise protected from insects, in all markets, stores, street stands, hotels, restaurants and boarding houses. Flies must not be allowed to congregate around food stalls. Cockroaches must be eliminated from all hotels, restaurants and boarding houses. Foods infested by insects should be subject to condemnation and destruction. Insect contamination of food is dangerous. 2. Hotels, public institutions, and lodging houses shall be required to keep their premises free of bedbugs. Bedbugs carry disease. 8. All school children shall be inspected at the beginning of each new school year for head lice, and oftener if circumstances warrant. In case the children are infested they should be isolated and sent to some clinic where they can be freed of the lice. All prisoners, patients in hospitals, and applicants at municipal lodging houses should be in- spected for head, body, and crab lice, and if infested should be bathed and their clothing condemned or cleaned. Lice carry many diseases and every opportunity should be taken which will enable the authorities to reduce their incidence. 4, All livery stables shall be required to remove all manure to the country daily, unless specified places for dumping are set aside. All private stables should be provided with a fly-proof box or a maggot- | i \ NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 41 trap platform for the storage of manure and should have the manure removed at least every 10 days. 5. Garbage should be removed daily from all places where it accu- mulates in large quantities, and two or three times a week from private residences. All garbage awaiting removal should be kept in closed cans. Garbage must not be dumped within the city limits unless it is dumped on incinerators where fires will soon consume it. These require- ments are necessary to keep down fly breeding. 6. Tin cans, bottles, and receptacles which will hold water, must not be allowed to accumulate in back yards, alleys or vacant lots, nor may they be dumped within the city limits or near residential sections in the suburbs, because they furnish excellent breeding quarters for mosquitoes. 7. The city should be connected for sewers as far into the suburbs as practicable, and all suburban properties not so connected should be required to install fly-proof cesspools, or septic tanks, or to arrange by neighborhoods for independent sewage with a common septic tank; or in the absence of water and necessary plumbing, to install sanitary privies, and be required to have all excreta removed once a week to an incinerator or other type of refuse disposal plant. Open vault privies-should not be permitted in the city. Indiscriminate defecation on streets, alleys, vacant lots, etc., should be strictly forbidden and punishable by law. 8. Packing houses, candy factories, syrup factories, and all other manufacturing institutions producing food products should be required to screen windows and entrances, and to use fly traps in such a way as to minimize to the utmost the access of flies and other insects to the food products. Especial attention should be given to the prevention of insect breeding on such premises. INDUSTRIAL SANITATION Many industries have important entomological sanitary problems in the preservation of their products from insect contamination and in the efforts to conform to sanitary regulations. There are many times when they would be able to use the services of a consulting sanitary entomologist to advantage. The keynote of industry today is the prevention or utilization of waste. Insect depredations on food products cause waste because the public does not want polluted food, and because sanitary inspectors are becoming more and more alive to the menace to health from insect pol- luted foods. It is not generally understood that the presence of weevils and worms in cereal foods may do more than destroy the food. The evidence is 42 SANITARY ENTOMOLOGY growing against these insects from the sanitary standpoint. Some of these insects contain substances in their bodies which are highly toxic, as for instance Sitophilus granarius, the granary weevil, contains the poisonous substance cantharidin. There are numerous instances of the sickening of animals from eating weevily grain. Still more important is the fact that where grain is accessible both to rodents and insects, certain parasitic worms pass out in the feces of the rodent in the egg stage, are eaten by the insect larvae in the grain, pass part of their life cycle in the insect, and the insect is then possibly eaten by a rodent, in which the worm completes its life cycle; or sometimes in our breakfast foods we eat these parasitized insects and become infected with the worms. For example, the rat tapeworm, Hymenolepis diminuta (Rudolphi) infests various species of rats, but sometimes is found in man. Joyeux has proved that its commonest intermediate host is the meal moth, Asopia farinalis, which becomes infected by eating the tapeworm eggs, in the larval stage. Grassi and Rovelli found the cysticercoid in the larva and adult of this moth and also in the earwig, Anisolabis annulipes and the beetles Akis spinosa and Scaurus striatus. Joyeux found that the adults of the granary beetle, Tenebrio molitor, easily took up the eggs. A cysticercoid or larval stage resembling the mouse tapeworm Hymenolepis microstoma (Dujardin) has been found by Grassi and Rovelli in the beetle Tenebrio molitor. The whole problem, therefore, of the control of stored food product insects is of vital importance to the manufacturers of food. Syrup factories, sugar mills and refineries, ice cream factories, cream- eries, and candy factories offer great attractions to flies which may alight on the exposed products and deposit with their feet, or in their vomit or excreta, germs of disease taken up elsewhere, perhaps days before when the fly was a larva breeding in excrement, and these germs may find the sweets excellent culture media for extensive growth. Extraor- dinary means must be devised to keep flies away from such products. Packinghouses offer abundant attractions to many kinds of insects, many of which are serious disease carriers. Railroad trains are the means of conveying from place to place disease-carrying mosquitoes, flies, roaches, fleas, lice, bedbugs, and mites. Fumigation of railway cars is an essential entomological control measure. Dairies are often found to be the foci of the spread of typhoid fever, and knowing the propensity of the house fly we can see how readily it can carry the organisms from the stools of a sick person to the milk pails in the dairy. There needs to be rigid control of flies in all dairies. These are but examples of many industries which have problems in sanitary entomology. CHAPTER IV A General Survey of the Seriousness of Insect-Borne Diseases to Armies ? W. Dwight Pierce As this course of study is directed primarily toward obtaining a thorough knowledge of the relations of insects to diseases of men and the measures which must be taken to prevent these diseases, it is eminently proper for us to make a survey of the insect problems which confront the greatest aggregations of men, the modern army. From a study of mili- tary sanitation methods we may learn much which we need to know in practical municipal problems. Military methods are based on the neces- sity of quick returns and emergency efficiency, from which are built up in permanent establishments more perfect measures. The discussion of military entomology immediately falls into two very distinct lines: first, the army training and concentration camps, and second, the active service camps and battle conditions. Before the location of the average training camp, we may assume that it is possible to deliberate more or less on the desirability of one or more sites and that in a general way drinking water and general health conditions are considered. Not infrequently some other consideration will outweigh sanitation, as when it is considered essential to place a camp near a certain city or on a certain waterway or railway. In such cases of expediency, we are quite likely to find sanitation a serious problem from the outset. The camp site is selected because of some important reason. From an entomologist’s viewpoint a number of outstanding questions immediately arise as to this site. Is the ground open or wooded, level or sloping and well drained? Are there water holes, running streams, or swamps in the camp area or nearby? Are there farmhouses, stables, or other buildings on the site and what is the entomological situation in these buildings? What disease-carrying insects are naturally breeding about the camp site? If there has been any contagious disease of man or animals in the community before the camp was located, the entomolo- gist’s concern is the greater. He should if possible learn the focus of 1This lecture was originally presented May 27, 1918, and distributed the same day. It has been revised for the present edition. 43 44 SANITARY ENTOMOLOGY that disease and the insect conditions of that focus. The original health conditions on the site may have a distinct bearing on later events. Often the first arrivals at the camp site are contractors with multi- tudes of laborers and animals collected from everywhere, and from every stratum of society. There are few hygienic arrangements for these men. In fact, the contractors are aiming to obtain as large profits as possible, and therefore hold down the expenses for sanitary waste disposal. Some among these laborers are almost certain to bring lice, bedbugs, fleas, and possibly also scabies mites, on their bodies and clothes. Thrown together indiscriminately in hastily constructed barracks, there is soon a general distribution of vermin. Their animals are quite likely to be infected with scabies mites and possibly other mites, and with bots and ticks. The undisciplined assembling of many animals and carelessness about manure disposal offers great attractiveness to all flics and insects attracted by animals. It is probable that many dogs accompany the laborers and contribute their quota of fleas. It is almost impossible with crude, unedu- cated laboring men to get them to maintain sanitary conditions. Indis- criminate defecation, the scattering of garbage, the accumulation of manure, personal uncleanliness, all contribute to make contractor camps sanitary sore spots. ‘ Sooner or later the sanitarians arrive on the spot, very likely with a squad or company of raw untrained labor troops, and the clean-up begins. We can expect a constant lack of coordination between the military and the civilian. As for example, at one camp the sanitary officers had constructed drainage ditches to carry off surplus standing water, but the laborers persisted in throwing scraps of wood, underbrush and waste into the ditches so that they were of no avail, or rather so that they formed traps for water pools. During the transition period when the camp is part civilian and part military there will be two very different types of conditions existing side by side, one good, one bad. Of course the army sanitarians have supervision over these civilian camps, but they find difficulty in enforcing sanitation. | When a camp is placed like Camp Humphreys, Virginia, on a tongue of land between two shallow bays of water that are known to fill up with vegetation, and which furnish breeding places for millions of mosquitoes, and with typical swamp lands at the heads of these bays, we may readily see that the task of the sanitary officer is not an easy one. These bays are moreover at tidal level and the daily fluctuations of the water add complications to the drainage problem. Each individual camp, wherever located, will present its own type of problems, and necessitates an early and thorough entomological survey. The tremendous speed of construction and the rapid arrivals of fresh SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 45 contingents of troops and animals in a new army camp make the first months of the entomological sanitarian very busy ones. Common sense is one of the primary essentials in meeting the exigencies of the situation. The possibility of mosquito breeding must be kept at a minimum in spite of temporary drainage, multitudes of borrow pits, tree stumps, fire-water barrels, etc. A system of manure, garbage, refuse, and fecal disposal is of necessity hastily devised and must keep pace with the increasing numbers of men and animals. This waste disposal is handled by special units and the sanitarian acts only in an advisory capacity. He needs therefore to be very vigilant in his inspections. Army camps nowadays grow in such marvelous proportions that past experiences are of little avail. The man on the ground must be well versed in the principles of entomological sanitation and must use his judgment for all it is worth. The constant accessions in troops and raw recruits call for constant scouting and prophylaxis to prevent admission of vermin. The work against vermin almost necessitates a specialist to take care of it alone. In fact it were best if three entomologists were located in each camp, one looking after the suppression of water and moist earth breeding insects, one looking after the suppression of fecal, waste, and manure breeding insects, and the third handling the vermin of the person and the barracks. So serious is the vermin problem in all armies that elaborate measures have to be taken to combat it. The Germans developed great vacuum tubes that will contain an entire railroad coach. The Russians, and then other nations, developed bath trains sufficient to handle the cleansing of thousands of men a day. The Russians and Roumanians developed sod houses for heat sterilization of clothing. Heat and steam sterilizing plants of many types have been devised. A tremendous amount of experimen- tation has been directed toward chemical cleansing of the clothing. The destruction of waste is such an acute problem that many types of incinerators have resulted (see figs. 1, 2, 3), but as a camp becomes permanently organized the sewage system does away with many of the early difficulties. Permanent incinerators, well kept drainage systems, organized removal of the manure, and disposal of garbage by the quarter- master’s department, systematic inspection of quarters and grounds, and systematic bathing and cleansing of clothing, characterize the perfectly adjusted sanitation of a permanent’ camp. Every large army camp has its remount camp and company stables, The farther these stables are located from the soldiers’ barracks the better will be the fly conditions in the living quarters of the men. The actively engaged army, however, presents entirely different con- ditions. There is no possibility of developing sewage systems, but tem- porary latrines must be substituted (see figs. 4, 5, 6, 7). Manure and garbage cannot be farmed out to contractors, but must be disposed of 46 SANITARY ENTOMOLOGY Fic. 1—Cross section of Mann’s hillside incinerator, used at U. S. Marine Camp, Quantico, Va. (Mann). dorbage Fic. 2.—Modification of Mann’s hillside incinerator, adapting it to level ground (Mann). eolid refuse _semovable cots bars \iquid refuse, can eae Fic. 3.—Small incinerator of the Ferguson type, for use of small units, and capable of transportation (Mann). SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 47 Fic. 4.—Straddle trench latrines, 1 foot wide, 2 feet deep, 3 feet long, for field opera- tions at temporary locations (Mann). == =z in = — = SS eo = = = 2 aa} Fie. 5.—Covered pit latrine level with ground, a semi-permanent type (Mann). YL ZF ee Fig. 6.—Garbage can with top converted into portable urinal for use in company street at night (Mann). 48 SANITARY ENTOMOLOGY by hastily built incinerators, or the manure stacked and treated to kill flies. Ditches and standing water cannot be drained. They must be treated to kill insect life in them. Temporary hospitals abound and must be protected from flies and vermin. The men sleep out of doors or in scanty shelters, even in pig pens, barns, etc., wherever they can find shelter in inclement weather. Insect infestation in these must be reduced to a minimum. When lice abound, hastily constructed devices must be installed or the clothing treated by chemicals. The trenches and dugouts have to be sprayed with creosote oils to keep away flies and kill vermin. Terrible stenches arise from dead bodies and these must be buried or treated to prevent fly breeding. In other words, everything here must be done hastily but Fic. 7—Urine soakage pit, in cross section (Mann’s modification from Lelean). effectively, for tomorrow the work may have to be done all over some- where beyond or behind. The larger the body of men assembled and the greater the carnage, the more serious the diseases of all kinds and especially those carried by insects. In the great European War the greatest diseases were those borne by lice. In fact there is plenty of evidence that louse-borne diseases have been among the worst in many wars of the past. Three serious diseases which ravaged the trenches are carried only by lice,—typhus fever, trench fever, and European relapsing fever. Millions of the Serbian nation were wiped out by typhus fever. The Roumanian nation was swept by typhus and relapsing fever. Russia, Germany, Austria and France suffered terribly from these louse-borne diseases. Trench fever spread back from the trenches into the cities. And yet all of these diseases can be controlled absolutely by suppressing the lice. It is easy to see how serious it is if a case of any of these diseases enters the SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 49 trenches. The lice spread from man to man, and they are noted for leaving a man with feverish conditions for a normal man. Another disease which has been especially bothersome in the trenches is scabies. Both horses and men are seriously afflicted with this mite disease, and special veterinary hospitals were constructed in France solely for handling horse scabies. In malarious countries where mosquitoes are breeding in great num- bers, malaria is a very serious camp and army problem. Campaigns in tropical countries are endangered often by yellow fever, dengue and filariasis, which are also mosquito-borne diseases. The troops engaged in Asia and some parts of the Mediterranean lit- toral had to contend with the possibilities of plague outbreaks. Troops engaged in the African campaigns had to deal with trypanosome and spirochete diseases. Along the Mediterranean littoral pappataci fever is to be seriously considered. For example, a detachment of the British Army in Egypt was suddenly attacked by an outbreak of this disease. We are all familiar with the disaster of our Spanish-American War in which so many thousands were carried away by typhoid fever, dysen- tery and diarrhea, all fly-borne diseases. In the present war, to these must be added Asiatic cholera, also borne by the fly. The great quantity of carcasses on the battlefield gives rise to myriads of flesh and carrion flies and as a consequence of the habit of these flies of attacking wounds of living people, there were many cases of human as well as animal anthrax in the European War. These are only the more important army diseases carried by insects. One of the greatest dangers to troops in active service lies in their moving into countries with obscure or little studied diseases, or diseases against which the men have had no chance to develop immunity, CHAPTER V Relation of Insects to the Parasitic Worms of Vertebrates 4 B. H. Ransom The only important part insects are known to play in the propagation of parasitic worms that affect human beings and other vertebrates is that of true intermediate hosts necessary to the existence of the parasites in some of their stages of development. Observations have been recorded in the literature showing that flies and other insects may swallow the eggs of various parasites of man such as hookworms, whipworms and other nematodes in whose life history no intermediate hosts are required, also the eggs of tapeworms in whose normal life history it is known that insects are not concerned, for example, Taenia saginata, whose inter- mediate host is the ox. It has been supposed that insects may thus act as mechanical carriers for such parasites, but as a matter of fact definite evidence of the importance of insects as mechanical carriers of the eggs or larvae of parasitic worms has not yet been brought forth. On the contrary there are reasons to suppose that in some cases at least the swallowing of the eggs or larvae of parasites by insects that can act only as mechanical carriers and not as intermediate hosts, reduces rather than increases the chances of the young parasites continuing their development and reaching a host in which they can become mature. Among the parasitic worms affecting man and other vertebrates it is those forms requiring intermediate hosts, so-called heteroxenous parasites, that are of special interest so far'as insect transmission is concerned. The monoxenous parasites, or those requiring no intermediate host, may practically be left out of consideration, with the admission that the mechanical carriage of monoxenous parasitic worms by insects may in the future be proved to have an importance not yet demonstrated. A complete demonstration of the part played by an insect in the life history of a given species of parasite is often a difficult matter. The animal which serves as the final host may be subject to infection not only with the species of parasite under investigation but also with other species liable to be confused with it in some of its stages. The insect 1This lecture was read to the class on December 16, 1918, and distributed January, 1919. It has been revised up to date. The names of insects have been revised by the editor. 50 RELATION OF INSECTS TO THE PARASITIC WORMS 51 may likewise harbor parasites other than the one that is being studied. The possibilities of confusion and of the entrance of extraneous factors into the problem are so many and so varied that in most cases it is only after the most rigorously controlled experiments, combined with careful comparative studies of the successive stages of the parasite, that conclusions may safely be drawn. Furthermore, in working out the life history of a parasitic worm it is not sufficient to prove that insects of a certain species can act as intermediate hosts under experimental condi- tions. Some species of parasitic worms are able to develop in more than one species of insect, and the fact that a certain parasite can develop in a certain insect does not necessarily mean that under natural conditions the species of insect in question serves as the intermediate host of the parasite. For example, one of the common parasites of sheep and cattle is able to pass through its larval stages in cockroaches. These insects become readily infected if the eggs of the parasite which occur in the feces of the final host animals are fed to them. Under natural conditions, however, cockroaches do not ingest the feces of sheep and cattle, nor are. they found in places where they are likely to be picked up by sheep and cattle. Besides cockroaches, various species of dung beetles have been shown to be capable of acting as intermediate hosts of the parasite in question, and it is evident that these insects are the natural intermediate hosts. Unlike cockroaches they have plenty of opportunity both of becoming infected and of passing on their infection to the final hosts. A more or less intimate environmental relationship between the insect host and the final host generally exists in the case of parasites transmitted ‘by insects. In a number of cases the insects are coprophagous and also likely to be ingested by the final hosts, as in the instance just cited. Another highly interesting group of cases is that in which the insects are ectoparasites on the final hosts, or bloodsuckers that periodically visit them, and thus have particularly favorable opportunities for becom- ing infected with parasitic worms harbored by the animals they attack and in turn reinfecting the latter. MODE OF INFECTION OF INSECT HOSTS As already stated the part which insects may take in the propagation of parasitic worms of higher animals is that of intermediate hosts, in which certain larval stages of the parasites are passed before they are ready to enter the bodies of their final or definitive hosts in which they develop to maturity. The way in which the insects become infected varies with different species of parasites. In the case of some species which live in the alimentary tract of the final host the eggs or larvae are dis- charged from the. body of the host in the feces. Coprophagous insects 52 SANITARY ENTOMOLOGY swallow the eggs and if they are suitable intermediate hosts for the parasites the young worms go through several developmental stages and finally within the bodies of the insects reach a stage in which they are ready to be introduced into the body of the final host. Certain parasites whose adult stages live in relation with the blood vessels of the final host discharge their young into the blood stream whence they may be ingested by bloodsucking insects in whose ‘bodies they undergo development to a stage infective for the final host. Aquatic insects may swallow free-living larval stages of parasites, or may be actively attacked by larval para- sites which gain entrance to their bodies by penetrating the cuticle. These insects may in turn be eaten by other insects and the infection thus passed on to them. In some cases the parasites may be taken up by insects or enter their bodies during an early stage of development of the insects and persist in later stages. Infection may thus occur during one stage of the insect but the development of the parasite to a stage infective for the final host may not be completed until after the insect has reached a later stage. Thus flies become infected with a certain parasite of the horse during the maggot stage, but the young parasites do not become suffi- ciently developed to be returned to the final host until the flies have reached the pupal or adult stage. MODE OF INFECTION OF VERTEBRATE HOSTS Parasitic worms that have insects for intermediate hosts reach their final hosts in various ways. In the case of some species the insect hosts are swallowed either as the habitual food of the final hosts, or incidentally with food or drink. In other instances the young worm may have already escaped from its insect host before it is taken in with food or drink by its final host. The cases of accidental infection with horse- hair worms not normally parasites of human beings are likely to have happened in this way. The parasites of which bloodsucking insects are intermediate hosts may be introduced into their final hosts as a result of the escape of the larval parasites from the insects at a time when the insects are drawing blood. Commonly the larve burst through a weak spot in the cuticle of the insect and then burrow into the skin of the final host. SPECIES OF WORMS FOUND IN INSECTS The parasitic worms of the higher animals in whose life history insects and insect-like organisms play a part, belong to two large zoological groups, Plathelminthes and Nemathelminthes. The former may be sub- divided so far as concerns parasitic forms into Cestoda, or tapeworms, RELATION OF INSECTS TO THE PARASITIC WORMS 53 and Trematoda, or flukes; the latter into Nematoda, or roundworms in the restricted sense, Gordiacea, or horse-hair worms, and Acanthocephala, or thorn-headed worms. CESTODA OR TAPEWORMS All tapeworms whose life history has been well established require an intermediate host, and are thus heteroxenous parasites. A typical life history of a tapeworm is as follows: The adult lives in the intestine of the final host. The eggs pass out of the body of the infested animal in the feces. The feces or food or drink contaminated by them are swallowed by an animal that can act as an intermediate host. The eggs thus reaching the intermediate host hatch in the alimentary tract and the embryos set free migrate into nearby or remote tissues of the body, developing finally into an intermediate stage, commonly of the type known as a cysticercoid, in the case of those tapeworms whose intermediate stages occur in insects. Having reached this stage further development of the parasite awaits the time when the intermediate host or infested por- tions of its body are swallowed by an animal that can act as the final host, whereupon it resumes its development and, becoming mature, completes the life cycle. About 100 species of tapeworms are known whose adult stages occur in man or domestic animals. Four of these, Dipylidium caninum (the double-pored tapeworm of the dog, cat, and man), Hymen- olepis diminuta (the yellow-spotted tapeworm of rats, mice, and man), Hymenolepis nana (the dwarf tapeworm of rats, mice, and man), and Choanotenia infundibulum (one of the tapeworms of the domestic fowl), have insects as intermediate hosts, with the possible exception of the dwarf tapeworm, in whose life history the part played by insects has not been definitely determined. Dipylidium caninum (Linneus, 1758) Railliet, 1892 This tapeworm, sometimes called the double-pored dog tapeworm, is of very common occurrence in the small intestine of dogs and cats, and of occasional occurrence in human beings. Its larval stage (cysticercoid) occurs in the biting dog louse [T'richodectes latus (canis)] as deter- mined experimentally by Melnikov (1869), and in fleas (Ctenocephalus canis, C. felis, and Pulex irritans). Fleas apparently are the usual intermediate hosts. Grassi and Rovelli (1888, 1889) followed the various stages of laryal development in adult fleas, from the hexacanth embryo to the fully developed cysticercoid, and as they failed to find the parasite in larval fleas concluded that only adult fleas can act as hosts. Recently, however, Joyeux (1916) has reached the conclusion that adult fleas 54 SANITARY ENTOMOLOGY are unable to swallow the eggs of the tapeworm. He finds that larval fleas readily swallow the eggs; these hatch in the intestine of the insect, and the embryos thus released penetrate into the body cavity. They per- sist in the hexacanth stage until the transformation of the flea into the adult, after which they proceed with their development and in a short time reach the cysticercoid stage. Infection of the dog, cat, or human being occurs naturally as a result of swallowing infested fleas. Fleas are exposed to infection owing to the fact that their larve live in an environment likely to be contaminated by the feces of infested dogs or cats. The eggs of the tapeworm as passed in the feces are grouped in capsules containing about a dozen eggs, so that infection of the insect host is likely to be multiple. The double-pored tapeworm is relatively uncommon in man and most of the cases recorded, of which there have been less than 100 all told, three in the United States, are among young children. Children are more likely than adult human beings to swallow fleas, which would explain the greater frequency of infestation among children. Another possible explanation of the more common occurrence of this parasiteeamong children than among adults is that older persons may possess a greater immunity to infection. Prophylaxis against the double-pored tapeworm consists chiefly in keeping dogs and cats free from lice and fleas, and so far as human beings are concerned excluding dogs and cats, especially if they are lousy or infested with fleas, from human habitations. Hymenolepis diminuta (Rudolphi, 1819) Blanchard, 1891 Hymenolepis diminuta (the yellow-spotted tapeworm) is of frequent occurrence in the small intestine of rats and mice, particularly the former, and of occasional occurrence in the intestine of man. The adaptability of the adult tapeworm to hosts so widely different as rodents and human beings is paralleled by the adaptability of the larval stage to various intermediate hosts. Cysticercoids belonging to this species have been . recorded in various insects, a Lepidopteron, Asopia farinalis, in both larva and imago; a Dermapteron, Anisolabis annulipes; Coleoptera, Akis spinosa, Scaurus striatus, and Tenebrio molitor; and fleas Ceratophyllus fasciatus, Xenopsylla cheopis, Pulex irritans, and Ctenocephalus canis; also in myriapods, Fontaria virginiensis and Julus sp. Nicoll and Minchin (1911) found the cysticercoids in about 4 per cent of the rat fleas (8 out of 207) they examined during a period of thirteen months, and they succeeded in infecting rats with the tapeworm by feeding them fleas, as Grassi and Rovelli (1892) had previously done by feeding other insects. Joyeux (1916) infected the larvae of Asopia farinalis by feeding the eggs of H. diminuta and believes the cysticercoids recorded in the RELATION OF INSECTS TO THE PARASITIC WORMS _ 55 adult moth by Grassi and Rovelli were carried over from the larval stage of the insect. He failed in his attempts to infect Forficula auricularia, Blatta orientalis, and Blattella germanica. He also failed to infect beetles belonging to the species Blaps mortisaga, but succeeded easily in infecting the adults of Tenebrio molitor. The larve of this latter beetle according to Joyeux are incapable of acting as intermediate hosts of H. diminuta. He was able to infect the larve of rat fleas and of Pulex irritans and Ctenocephalus canis. In these insects the embryos of H. diminuta begin immediately to develop into cysticercoids and do not wait for the transformation of the larval fleas into adults, as Joyeux found in the case of Dipylidium caninum, the embryos of which apparently lie dormant in the insect until after it transforms into the adult stage. In this country Nickerson (1911) has reared the cysticercoid in myriapods, Fontaria virginiensis and Julus sp., fed on the eggs of the tapeworm. He failed in his attempts to infect meal worms. It is evident that infection of the definitive host with H. diminuta results from swallowing infested insects, the latter having become infested as a result of swallowing the eggs contained in the feces of animals harbor- ing the tapeworms. As a parasite of man in the United States, so far as available statistics show, H. diminuta ranks about third in frequency among the tapeworms, the beef tapeworm (Twnia saginata) being the most common, and the dwarf tapeworm (H. nana) being next. Evident prophylactic measures are those directed toward the destruction of rats and mice and the avoidance of the ingestion by human beings of the various insects that may serve as intermediate hosts, especially the pro- tection of farinaceous foods from insect infestation. Hymenolepis nana (Siebold, 1852) Blanchard, 1891 Hymenolepis nana (the dwarf tapeworm) is a very common intestinal parasite of rats and mice and is of rather frequent occurrence in man, especially in children. In the United States it ranks second to the beef tapeworm in the order of frequency among the tapeworms of man. Its life history has not been fully worked out. Grassi (1887), however, has found that cysticercoids develop in the intestinal villi of rats that have been fed the eggs of the dwarf tapeworm. According to his view the cysticercoids later break out of the villi into the lumen of the intes- tine and grow into mature tapeworms. The rat thus acts both as inter- mediate and definitive host of the dwarf tapeworm, the parasite being spread from one rat to another through the medium of the eggs passed in the feces. The dwarf tapeworm, according to Grassi’s version of the life cycle, is an exception to the rule among tapeworms that the adult -stage occurs in one species of animal and the larval stage in another 56 SANITARY ENTOMOLOGY species likely to be eaten by animals of the species that harbors the adult tapeworm. Inasmuch as Nicoll and Minchin (1911) have found cysticercoids in a rat flea (Ceratophyllus fasciatus) that in details of head structure are apparently exactly similar to and specifically identical with the dwarf tapeworm, the question arises whether such insects may not act as inter- mediate hosts, and whether in addition to the life cycle of an exceptional type described by Grassi, the dwarf tapeworm also has a life cycle of the ordinary type. T. H. Johnston has found cysticercoids similar to those recorded by Nicoll and Minchin in another species of rat flea (Xenopsylla cheopis) as well as in Ceratophyllus fasciatus. Joyeux (1916) has failed in experiments with fleas belonging to the species named and to related species, to infect them with H. nana. He states he used both larval and adult fleas. On the other hand he was able to confirm Grassi’s results and succeeded in infecting a large number of rats and mice by feeding them the eggs of the tapeworm. The experi- mental evidence thus far available accordingly favors the view that insects do not play a necessary part in the life history of the dwarf tapeworm. Furthermore, considering the frequency of occurrence of H. nana as a parasite of man, and the enormous numbers of the parasites sometimes present, it would seem that infection is more likely to occur in the manner described by Gragsi than as a result of swallowing rat fleas, there being of course a greater likelihood of human beings swallowing rat feces or fecal matter from other human beings containing large numbers of eggs of the tapeworm than of swallowing rat fleas containing a sufficient num- ber of cysticercoids to develop into the large number of tapeworms that have been found in some cases. Choanotenia infundibulum (Bloch, 1779) Cohn, 1899 Choanotenia infundibulum is a common tapeworm of chickens in various parts of the world. Grassi and Rovelli (1892) in Italy found cysticercoids in the common house fly (Musca domestica) which on account of their morphological similarity to Choanotenia infundibulum they inferred belonged to this species. From the results of experiments conducted in this country by Guberlet (1916) it appears safe to conclude that the common house fly acts as the intermediate host of the tapeworm, Choanotenia infundibulum, infection of the fly apparently occurring as a result of swallowing the eggs of the tapeworm, and the chicken in turn acquiring the parasite as a result of swallowing flies infested with the cysticercoid stage. Whether infection of the fly reg ularly occurs during the larval or during the adult stage, or during both stages, has not been definitely settled. RELATION OF INSECTS TO THE PARASITIC WORMS 57 Prophylaxis in the case of this tapeworm is obviously largely dependent upon fly control measures. Other Tapeworms According to Villot (1883) the larval tapeworm observed by Stein (1852) in the larva of Tenebrio molitor belongs to the tapeworm of the mouse, known as Hymenolepis microstoma. The same writer (1878, 1883) also associates with certain tapeworms of shrews, two species of larval tapeworms which he found in myriapods, Glomeris limbata. Fur- ther investigations of these parasites appear necessary to substantiate the views held by Villot as to their specific identity. Ackert (1918, 1919) has recently recorded some experiments in which chickens were given house flies and became infested with tapeworms (Davainea cesticillus and D. tetragona). The immature stages of these parasites were not, how- ever, seen in the flies and the possibility is not excluded that the chickens became infected from some source other than the flies, notwithstanding the precautions taken against extraneous infection. Guberlet (1919) caught stable flies (Stomoxys calcitrans) in poultry yards where the chickens were commonly infested with Hymenolepis carioca (Magalhiaes, 1898) and fed them to young chicks with the result that some of them became infested with this tapeworm. He concludes that the stable fly possibly serves as an intermediate host of this tapeworm. TREMATODA OR FLUKES All species of flukes whose life history is known depend upon molluscs as hosts for certain larval stages, and they may or may not require one or more additional intermediate hosts before they reach the definitive host. It is as intermediate hosts following the first intermediate host, a mollusc, that insects can play a part in the propagation of flukes. As yet it has not been shown that insects are concerned in the life history of any of the flukes (about 100 known species) that affect human beings or domestic animals, but as the life history of all of these parasites has not been determined it is quite likely that in the case of some species insects will be found to act as intermediate hosts. Different species and groups of species show various types of life history with reference to the number of larval stages through which the parasite passes and the number of intermediate hosts required. A comparatively simple life cycle is as follows: ‘The mature fluke in the definitive host produces eggs which pass to the exterior inthe feces. Under suitable conditions of moisture and temperature the egg hatches and a ciliated larva, the. miracidium, issues. If this miracidiwm finds a suitable mollusc (different species of molluscs 58 SANITARY ENTOMOLOGY attract different species of miracidia) it burrows into the soft tissues of the mollusc and reaching the respiratory chamber proceeds to develop into the next stage, the sporocyst. Within the sporocyst by a process of internal budding more or less numerous so-called rediw develop. The rediz finally leave the sporocyst and migrate into the liver of the mollusc. In the redia several generations of daughter redie may develop by budding. The next stage, developed also by internal budding from the redia, is the cercaria. The cercaria of some species is provided with a tail by means of which it swims about in the water when it finally escapes from the mollusc. The cercaria may be swallowed by or actively pene- trate into some animal and become encysted in this animal. Finally when the animal harboring encysted immature flukes is swallowed by an animal which can serve as a host of the adult fluke, the young flukes thus reach- ing their definitive host develop to maturity and the life cycle is complete. Following is given a partial list of the insects in which young flukes have been recorded. The species to which the young flukes in question have been assigned and the final host animals are also indicated. Further investigations are likely to show that some of the flukes from insects have been misidentified and do not belong to the species to which they have been supposed to belong, and the data given in the list should not be accepted as fully proved in any case, though there can be no doubt in some of the cases cited. No distinction has been made between certain and doubtful cases, except that a few that are doubtful are indicated by question marks. The determination of species of young flukes found in insects has generally been made solely upon their morphological similarity to adults occurring in vertebrate hosts and it is quite likely that mistakes have been made by investigators of these parasites just as mistakes have frequently been made in the association of immature and adult parasites belonging to other groups of worms. NEMATODA OR ROUNDWORMS Among parasitic worms the species of nematodes are more numerous than either the species of tapeworms or flukes. Nematodes as a group are not exclusively parasitic and thousands of free-living species are known to exist, although comparatively few have been described. Many species of nematodes are parasites of insects only and do not occur in other animals. Insects therefore harbor parasitic nematodes which belong to them exclusively as well as the larval stages of nematodes that occur in higher animals in their adult stage. The ubiquity of free-living nema- todes introduces a frequently troublesome complication into the study of the life histories of monoxenous parasitic nematodes of which there are many species, and the common occurrence of parasitic nematodes RELATION OF INSECTS TO THE LIFE CYCLE OF FLUKES Insect Host Adult Fluke, Final Host Coleoptera Ilybius fuliginosus (Fabricius) (adult) Haplometra cylindracea Frogs Water beetle (larva) Prosotocus confusus iB = “ Pleurogenes medians f ss * - ie claviger " Lepidoptera Nymphula nympheata (Linnzus) (larva) Unknown Unknown Diptera Anopheles maculipennis Meigen (claviger Fa- bricius) (adult) sé es Anopheles rossi Giles (adult) ss ae Chironomus plumosus Linneus (larva) Lecithodendrium ascidia Bats Culex quinquefasciatus Say (fatigans Wiede- mann) (adult) Unknown Unknown Trichoptera Anabolia nervosa (Leach) Curtis Allocreadium isoporum Cyprinoid fishes Anabolia nervosa (larva) Opisthioglyphe rastellus Frogs Cheetopteryx villosa (Fabricius) (larva) Allocreadium isoporum Cyprinoid fishes Drusus trifidus McLachlan (larva) Unknown Unknown Limnophilus rhombicus (Linnzus) (larva) Opisthioglyphe rastellus Frogs griseus (Linnzus) (larva) cs c cs “e lunatus (Curtis) (larva) Bi sé ee flavicornis (Fabricius) (larva) aS ee i Mystacides nigra (Linnzus) (larva) Unknown Unknown Notidobia ciliaris (Linneus) (larva) ss “ Phryganea sp. Lecithodendrium chilostomum | Bats Phryganea grandis (larva) Unknown Unknown Rhyacophila nubila Zetterstedt (larva) s Bats Neuroptera Sialis lutaria (Linneus) (larva) 8 Unknown Odonata A:schna (larva and adult) Prosotocus confusus Frogs Agrion (larva) Gorgodera pagenstecheri Wa ge ee varsoviensis es = Pleurogenes medians ss Calopteryx virgo (Linnzus) Halipegus ovocaudatus e “4 “(larva and adult) Pneumoneeces similis. ee Cordulia (larva) Prosotocus confusus ig Epitheca “ Gorgodera cygnoides __ se ae “ i pagenstecheri ee “ “s ss varsoviensis oi ’ Plectoptera sd a Cloeon dipterum (Linnzus) Stephens (larva) |?Opisthioglyphe rastellus aieares Ephemera vulgata Linneus (larva) Allocreadium isoporum Cyprnoid shes co 8 * ?Opisthioglyphe rastellus Frogs Ephemeridz (larva) Lecithodendrium ascidia Bats Plecoptera ; : Ree i Perlide (larva) Lecithodendrium ascidia “ “ Unknown Unknown 59 60 SANITARY ENTOMOLOGY among insects introduces an equally troublesome complication into the study of the life histories of the heteroxenous nematodes parasitic in higher animals, for which insects may serve as intermediate hosts. About 250 species of nematodes have been recorded as parasites of man and domestic animals. Many of these require no intermediate hosts, but some are heteroxenous parasites, and a number of these are known to have intermediate stages in insects and closely related arthropods. In the following discussion, in addition to the nematodes parasitic in man and domestic animals, certain species parasitic in other animals are also con- sidered because of the part played by insects in their life history. For convenience they may be placed in two groups, (1) those in which the eggs or first-stage larve leave the body of the final host in the feces, and (2) those in which the first-stage larve occur in the blood or lymph of the final host and leave the body through ingestion by bloodsucking insects. 1. Parasitic Nematodes Whose Eggs or Larve Leave the Body of the Final Host in the Feces Protospirura muris (Gmelin, 1790) Seurat, 1915 This nematode, parasitic in its adult stage in the stomach of various species of rats and mice, is of special interest historically as being the first parasite in whose transmission to its final host an insect was found to be concerned. Stein in 1852 recorded the presence of encysted nema- todes in the larve of meal beetles (Tenebrio molitor). WLeuckart (1867) and Marchi (1867) fed eggs of Protospirura muris (Spiroptera obtusa) to meal beetle larve and followed the development of the young nematodes up to the encysted stage found by Stein. This development is completed in about six weeks after ingestion of the eggs. The development to the adult stage was also followed in mice fed with the encysted nematodes from meal worms. Johnston (1913) has recorded encysted nematode larve which appeared to him identical with those of P. muris in the body cavity of a rat flea (Xenopsylla cheopis ). : Spirocerca sanguinolenta (Rudolphi, 1819) Railliet & Henry, 1911 The adults of this nematode live in tumors of the stomach and esophagus of the dog and the wolf. The eggs-unhatched pass out of the body of the dog in the feces. Grassi (1888) found encysted larval nem- atodes in cockroaches (Blatta orientalis) which he suspected were the larve of S. sanguinolenta. Dogs fed with these encysted nematodes after five days showed the larve free in the stomach; after ten days the young worms were further developed and were firmly. attached to the mucosa RELATION OF INSECTS TO THE PARASITIC WORMS 61 of the esophagus; and after fifteen days they had sunk themselves into the wall of the esophagus and had developed still further. Grassi con- cluded that cockroaches act as intermediate hosts, swallowing the eggs in the feces of infested dogs, and*in turn being swallowed by dogs. Seurat (1913), however, believes that Grassi was mistaken as to the identity of the encysted nematodes found in the cockroaches, and that they were really the larve of Spirura gastrophila, the adult of which occurs in the stomach of the cat, hedgehog (Erinaceus algirus ), and fox (Vulpes vulpes atlantica). Seurat (1912, 1916) finds what he considers to be the larve of S. sanguinolenta encysted in a great variety of animals including beetles, reptiles, birds, and mammals. The presence of the encapsulated larve in various vertebrates he explains as the result of the ingestion of insects infested with the larve. If the vertebrate is not a host in which the parasites can continue their development as they would in their normal host the dog, they migrate into the wall of the alimentary tract or mesentery and become reencysted without further development. If, however, the infested insect is swallowed by a dog the larve, after they have been freed by digestion of the cysts surrounding them, continue their development and finally reach maturity. Seurat in fact found that encysted larve in insects identified as those of S. sanguinolenta when fed to mice became reencysted in the manner described. Seurat (1916) records the following insects as hosts of the larve of §. sanguinolenta, all of them beetles: Scarabeus (Ateuchus) sacer, Scarabeus (Ateuchetus ) variolosus, Akis goryi, Geotrupes douei, Copris hispanus, and Gymno- pleurus sturmi. According to Seurat the life cycle of S. sanguinolenta would be as follows: The eggs pass out of .nfested dogs in the feces, are ingested by beetles, hatch, and the larve after a period of growth and development become encysted. If infested insects are swallowed by dogs or wolves the larval worms are released from their capsules and develop to maturity. If the insects are swallowed by other animals, the larve may become freed from their cysts as in the alimentary tract of the dog, but they are unable to develop further and leave the lumen of the alimentary tract and become reencysted in the tissues to which they migrate. In such a case, of course, there is a possibility of their resuming their development if the infested animal should afterwards be devoured by a dog or a wolf, but this possibility apparently has not yet been sub- stantiated. Spirura gastrophila (Mueller, 1894) Marotel, 1912 This nematode in the adult stage occurs in the stomach and the lower end of the esophagus of the cat. It has also been recorded by Seurat (1913) from the stomach of a hedgehog (Erinaceus algirus) and the stomach and esophagus of a fox (Vulpes vulpes atlantica), and by the 62 SANITARY ENTOMOLOGY same author (1918) in the esophagus of the mongoose (Herpestes ichneumon). This author identifies certain encysted larval nematodes found in a species of Onthophagus, in Blatta orientalis, in Blaps strauchi, and in Blaps sp. (near appendiculata) as belonging to 8. gastrophila. He thinks the parasites found in the cockroach and called Filaria ryti- pleurites by Deslongchamps (1824), and those identified as such by Galeb (1878) who associated them with an insufficiently described adult nematode of the rat, are probably the same as those he identified as the larve of S. gastrophila. He also dismisses Grassi’s experiments as insuffi- cient to show that the nematodes encysted in cockroaches are the larve of Spirocerca sanguinolenta as Grassi believed, and concludes that Grassi was mistaken and was really dealing with the larve of Spirura gastrophila. Seurat (1919) adds Akis goryi to the list of insect hosts of the larve of S. gastrophila, Gongylonema scutatum (Mueller, 1869) Railliet, 1892 This nematode in the adult stage is a common parasite in the mucous membrane of the esophagus of cattle, sheep, and other ruminants, and has also been recorded from the horse. Ransom and Hall (1915, 1916, 1917) have shown that various species of dung beetles (Aphodius femoralis, A. granarius, A. fimetarius, A. coloradensis, A. vittatus, Onthophagus hecate, and O. pennsylvanicus) act as intermediate hosts. Experimentally, cockroaches (Blattella germanica) can also be made to serve as intermediate hosts, a part of course which they do not play under natural conditions. The eggs_of the parasite pass out of the body of the definitive host in the feces and are swallowed by dung beetles. They hatch in these insects, and the larve entering the body cavity undergo a certain growth and development, reaching their infective stage in about a month, meanwhile becoming enveloped in capsules in which they lie in a coiled-up position. Further development waits upon the swallowing of the infested insect by a cow, sheep, or other suitable host as may readily occur while the animal is grazing, the insect being ingested with the herb- age upon which it happens to be. Following their ingestion by the defini- tive host, the larve are released from their capsules and develop to matur- ity. Seurat (1916) has described some larval nematodes from the abdom- inal cavity of Blaps strauchi, Blaps appendiculata, and Blaps sp. (near appendiculata) in Algeria that he identifies as Gongylonema scutatum. As pointed out by Ransom and Hall (1917), however, these evidently belong to another species as they do not correspond to the forms shown by these writers to be the larve of G. scutatum. Seurat (1919) adds Blaps emondi to the list of insects in which he has found the larve in question. RELATION OF INSECTS TO THE PARASITIC WORMS 63 Gongylonema mucronatum Seurat, 1916 This nematode occurs in the adult stage in the mucosa of the esophagus of the Algerian hedgehog (Erinaceus algirus). According to Seurat (1916) its larval stage is found encapsuled in the body cavity of various species of coprophagous beetles, Ateuchus sacer, Chironitis irroratus, Onthophagus bedeli, Gymnopleurus mopsus, Gymnopleurus sturmi, and Geotrupes douei, but there appears to have been some confusion as to the identity of the larve in question, and further investigation of the life history of this species is desirable (Ransom and Hall, 1917). Gongylonema brevispiculum Seurat, 1914 Seurat (1916), in addition to forms found in different species of Blaps that he considers to be third stage larve of Gongylonema scutatum, has described as second stage larve of G. scutatuwm some larval nematodes found encysted in the abdominal cavity of Blaps sp. and Blaps straucht in certain localities in Algeria. In a later paper, however (1919), he has expressed the opinion, based upon the morphology of the worms and a knowledge of the mammalian fauna in the region in which the parasites are found, that these larve are third stage larve and belong to the species G. brevispiculum the adult of which occurs parasitic in the cardiac portion of the stomach of a species of jerboa (Dipodillus campestris ). Further investigation seems desirable as to the identity of the supposed larve of Gongylonema brevispiculum as well as of the other larve of Gongylonema that have been assigned to various species on a basis of apparent morphological similarities and general considerations. A con- tinuation of the excellent work already done by Seurat relating to the larval forms of Gongylonema will no doubt clear up the confusion that now exists. Gongylonema neoplasticum (Fibiger and Ditlevsen, 1914) Ransom and Hall, 1916 rs This nematode occurs in the adult stage in the mucosa of the stomach, esophagus and mouth of the rat. It has been reared experimentally in the rabbit and guinea pig as well as in the rat and mouse. It is of special interest from the medical standpoint because it is commonly associated with and perhaps stands in etiological relationship to gastric carcinoma of rats. Fibiger and Ditlevsen (1914) have proved that cock- roaches (Periplaneta americana, Blatta orientalis, and Blattella german- ica), and a grain beetle (Tenebrio molitor) can act as intermediate hosts. The eggs are passed in the feces of infested rats and if ingested by one % \ 64 SANITARY ENTOMOLOGY of the insects named will hatch, the larve within twenty days after ingestion of the eggs developing to the infective stage. In this stage the larve are coiled up in cysts in the muscles of the prothorax and legs, differing in location from the larve of G. scutatum which in artificially infected cockroaches, as in their normal hosts, dung beetles, are found encysted in the body cavity. Arduenna strongylina (Rudolphi, 1819) Railliet and Henry, 1911 This nematode in its adult stage occurs in the stomach of the pig. Seurat (1916) has recorded the presence of larval nematodes in the stomach of a pig associated with adults of 4. strongylina which he con- siders belong to this species. He has found morphologically similar larval nematodes encapsuled in the body cavity of Aphodius rufus castaneus and states that they also occur in beetles of the genus Onthophagus. Ap- parently no feeding experiments have been carried out. Presumably the life history would be similar to that of Gongylonema scutatum, Proto- spirura muris, etc., that is, the eggs of the parasite passed in the feces are swallowed by beetles, the larve develop in these insects to the infective stage, and are transferred to the definitive host when the beetles are swallowed by a pig, after which the young worms complete their develop- ment to maturity. Seurat (1919) records the presence of encysted larve of A. strongylina in the stomach wall of the Algerian hedgehog (Erimaceus algirus). Apparently, therefore, the larve of this species that occur encysted in insects, like those of Physocephalus seralatus and Spirocerca sanguinolenta, if ingested by vertebrates other than the normal hosts of the adult worms, migrate out of the lumen of the digestive tract and become reencysted in the neighboring tissues. Physocephalus sexalatus (Molin, 1860) Diesing, 1861 The adults of this nematode live in the stomach of the pig, dromedary, and donkey. Seurat (1913) has found two successive larval stages pre- ceding the adult in the stomach of the definitive host (donkey) and has also (1916) established the common occurrence of the earlier of these two stages in various dung beetles (Scarabeus [Ateuchus] sacer, S. [Ateuchetus] variolosus, Geotrupes douei, Onthophagus nebulosus and O. bedeli). Pigs of course are commonly known to be coprophagus in their feeding habits and Seurat states that the donkeys of Algeria, where his investigations were made, commonly devour fecal matter swarming with dung beetles. The way in which the larve of P. seralatus reach their final host is therefore evidently through the ingestion of infested beetles by pigs, donkeys, or dromedaries. Presumably of course the beetles be- RELATION OF INSECTS TO THE PARASITIC WORMS 65 come infested by eating the eggs of the parasite which are passed in the feces of infested pigs, donkeys, and dromedaries. As in the case of Spirocerca sanguinolenta Seurat finds encysted larve of P. seralatus in various vertebrates in Algeria, particularly reptiles and insectivores. Their presence in these animals he would explain in the same way as he explains the presence of the encysted larve of S. sanguimolenta in such animals, that is, the larve present in insects devoured by the animals in question are unable to continue their development as they would in pigs and other suitable hosts. On the other hand they do not succumb in their strange environment nor do they pass through the alimentary tract with the feces but penetrate into the walls of the stomach and into other tissues and become reencysted, surviving in this condition more or less indefinitely. They may thus be considered parasites that have gone astray but still capable of existence in their abnormal environment. The possibility of their developing to maturity after reencystment in a strange host if this animal should be eaten by a pig has not been substantiated experimentally. Seurat (1916) has counted 4,880 larve identified as P. sevalatus in a single beetle, Scarabeus (Ateuchus) sacer. In addition there were 68 larve of Spirocerca sanguinolenta in the same beetle, making a total of 4,948 larve in the one insect. Habronema musce (Carter, 1861) Diesing, 1861 This nematode in the adult stage occurs in the stomach of horses and other equines, commonly in association with another closely related species, H. microstoma. The life history of H. musc@ has been shown to be as follows (Ransom, 1911, 1913; Hill, 1918; Bull, 1919): The eggs or the larve pass out of the body of the host in the feces. They enter the bodies of the larve of the common house fly, probably being swallowed,, though the mode of entrance has not been determined by direct observa- tion. The worm larve grow and develop in the developing flies and at about the time the adult insects emerge from the pupal stage the larve reach the infective stage. In this stage they are most commonly found in the proboscis. The ingestion by horses of flies harboring the larve brings the young parasites into the location where the adult occurs, and presumably this is the common method by which the larve reach their final host. The frequent swallowing of flies by horses is an undoubted fact. The mouths of horses are very attractive to house flies especially while the horses are eating, as any one can determine by a few minutes’ observation of the animals during the fly season. There is also another possible and very probable way in which the larve are transferred to horses, suggested of course by the habit of the larve of congregating in the proboscis of the fly. We may expect that it will be demonstrated 66 SANITARY ENTOMOLOGY in analogy with what has been shown to occur in Filaria transmission by mosquitoes, that the larve of H. musce can actively leave the proboscis of the fly while the insect is sucking moisture from the mouth or lips of the horse. There is already indirect evidence that this does occur. The researches of Descazeaux (1915), Bull (1916), and Van Saceghem (1917) have shown that the nematodes which occur in cutaneous granulo- mata and so-called summer sores of horses are morphologically similar to the larve of Habronema musce and in all probability*belong to this or a closely related species. Recently Van Saceghem (1918) from investi- gations carried out in Africa has reached the conclusion that the nematode of summer sores is Habronema musce and that it is introduced by flies. Larvae from infested flies were placed in the eye of a horse kept in an insect-proof enclosure, with the result that conjunctivitis and verminous nodules of the nictitating membrane developed. In another experiment two wounds were made on the skin of a horse, one protected against flies and the other left uncovered. The horse was placed in a stable in which 20 per cent of the flies were infested with Habronema. The unprotected wound became transformed into a typical summer sore. Bull (1919), who has made an extended study of cutaneous granulomata of horses in Australia, believes that the larve of Habronema megastoma are more often responsible for the production of habronemic granulomata than either H. musce or H. microstoma. Whether the Habronema larve in summer sores are able to migrate ultimately to the stomach and complete their development to maturity remains to be determined. Bull (1919) thinks it unlikely that the larve of Habronema are able to reach the alimentary canal from the submucosa of the external mucous membranes or from the subcutaneous tissues, and Hill (1918) also notes that the evidence of the occurrence of such a migration is quite insufficient. It is of interest to note that Habronema musce was known as a parasite of the fly long before its relation to the horse was demonstrated. Carter in 1861 was the first to record the presence of the nematodes in flies, following which they were frequently observed by entomologists and others who had occasion to examine the proboscis of the fly under the microscope. Larval nematodes very similar to H. musc@ have been seen in the proboscis of Stomoxys calcitrans by Johnston and others. The researches of Hill (1918) and Bull (1919) have shown that as far as their experience has gone the larve in this species of fly have invariably been Habronema microstoma so that the occurrence of H. musce in S. calcitrans appears questionable. The fact that these more or less injurious parasites of the horse depend upon flies for their existence is a point which may be added to RELATION OF INSECTS TO THE PARASITIC WORMS 67 those commonly used in arguments for the necessity of fly eradication. The possibility is also not excluded that flies may introduce Habronema larve into human beings, in whose tissues they may perhaps Le able to live for a time and do considerable damage. Though there is no evidence that this ever occurs, the possibility is one that deserves consideration from those who have opportunity to investigate the relation of flies to wounds and other lesions of the skin and mucous membranes. Habronema microstoma (Schneider, 1866) Ransom, 1911 Hill (1918) and Bull (1919) have shown that Habronema microstoma, which, like H. musca, occurs in the adult stage in the stomach of the horse and other equines, has a life history similar to that of H. musce. Both of these writers have occasionally observed the presence of H. microstoma in Musca domestica under experimental conditions but find that the usual intermediate host is Stomoxys calcitrans. As they repeatedly failed to infect §. calcitrans with the larve of H. musce@ it is probable that the forms from S. calcitrans reported by Johnston (1912) and others as H. musce were H. microstoma. Bull (1919) is of the opinion that the larve of H. microstoma may sometimes be concerned in the production of cutaneous granulomata of horses and that presumably they are introduced into the skin by the proboscis of an infested fly. Habronema megastoma (Rudolphi, 1819) Seurat, 1914 Habronema megastoma in its adult stage occurs in tumors in the stomach of horses and other equines. Hill (1918) and Bull (1919) have found that its life history is similar to that of H. musce, the house fly (Musca domestica) acting as intermediate host in both cases. Attempts to infect Stomowrys calcitrans with this species failed. Bull (1919) be- lieves that the larve of H. megastoma introduced by infested flies are the usual cause of habronemic granuloma of horses. So far as the normal life history of H. megastoma is concérned he thinks that the presence of the larve in the skin or mucous membranes of horses is to be considered accidental and that it is unlikely that they can reach the alimentary tract from such locations and become mature. According to his view, there- fore, which is shared by Hill (1918), H. megastoma and also the other species of Habronema reach the stomach of the horse as a result of the animal’s swallowing infested flies. Acuaria spiralis (Molin, 1858) Railliet, Henry and Sisoff, 1912 The adults of this nematode have been recorded as parasitic in the esophagus and stomach of the domestic fowl. Insects have not been 68 SANITARY ENTOMOLOGY shown to act as intermediate hosts, but insect-like animals commonly known as sow-bugs apparently act as intermediate hosts, Piana (1897) having found larval nematodes in an isopod (Porcellio levis) that corre- sponded in morphology with immature nematodes found in chickens harboring also the adult worms. Furthermore these larval nematodes occurred in sow-bugs only in the locality where the chickens were found to be infested. Although Piana identified the parasites that he found in chickens as Dispharagus nasutus (Rudolphi), it is apparent from his description and figures that they belonged to the species Acuaria spiralis (Molin). Filaria gallinarum Theiler, 1919 Theiler (1919) has recorded the occurrence of larval nematodes in a species of termite (Hodotermes pretoriensis). Among the termites only the workers were found to harbor these parasites, no infested soldiers having been discovered. Infested termites can easily be distinguished by the swollen abdomen which gives the insect a sort of balloon-like appearance. According to Theiler, on many South African farms the custom exists of digging up nests of termites and allowing the chickens to feed on the insects, and the droppings of chickens running in the fields are naturally scattered about and serve as food for the termites. Infested termites were fed to young chickens that had been hatched in an incubator. Adult worms that had evidently developed from the larve parasitic in the termites were found in the intestine or stomach in 15 out of 1 chickens that had been thus fed, but none were found in control chickens.: The proper generic position of this nematode described by Theiler as a Filaria remains to be determined. Ascaris lumbricoides Linneus, 1758 This common parasite of man has been definitely shown to have a direct life history without intermediate host. The opinion of Linstow (1886) that a species of Julus (guttulatus) acts as the intermediate host is without foundation. The common house fly may swallow eggs of this parasit2 as well as those of various other parasites which occur in the feces of infested human beings. The eggs pass through the intestine of the fly unhatched. Flies may thus scatter the eggs of Ascaris but there is no evidence that mechanical carriage of the eggs in this way assists materially in the spread of the parasite. There are various other natural agencies more effective than insects in spreading infection with parasites such as Ascaris. -Stiles, however (according to Nuttall, 1899), fed females of Ascaris lumbricoides containing eggs to fly larve (Musca domestica) and afterwards found the eggs in later stages of development RELATION OF INSECTS TO THE PARASITIC WORMS 69 in the pupe and adult flies that developed from the larve. This sug- gested the possibility that flies having become infested as larve might convey the parasite to man by falling into or depositing their excreta on food. Apparently these experiments have not been repeated. -2. Parasitic Nematodes Whose First-stage Larvae Occur in the Blood or Lymph of the Final Host and Leave the Body Through Ingestion by Bloodsucking Insects Filaria bancrofti Cobbold, 1877 This important parasite of man is widely distributed throughout the world in tropical and subtropical countries. It occurs in the United States, though apparently it is by no means common. Historically it is of special interest because of the fact that it is the species which Manson _ (1878) showed passed through certain metamorphoses in the bodies of mosquitoes after the larve had been sucked up by these insects in the blood of human beings affected with filariasis. Manson’s researches coupled with confirmatory work by other investigators established the novel fact of the transmission of an animal parasite by a bloodsucking insect, and may be taken as the starting point in the development of our knowledge concerning the part played by such insects in the spread of disease-causing organisms. Lewis had also observed the passage of the ‘arve from the human host into mosquitoes. The first observation of these larve in man was recorded by Demarquay in 1864 in Paris, the adult female was discovered by Bancroft in 1876 in Queensland, and the adult male by Bourne in 1888. The adults of this species live in the lymphatic system, both vessels and glands. The first-stage larve which are provided with a thin cutic- ular sheath, apparently the transformed egg shell, are found in the blood stream, usually periodically as first shown by Manson, that is, in consid- erable numbers only at night or rather during the hours of sleep, as the periodicity may be reversed by making the patient sleep during the day time. One of the names of the parasite, Filaria nocturna, is based upon the periodicity of the appearance of the larve in the blood. Various pathological conditions have been attributed to Filaria bancrofti such as adenitis, lymphangitis, abscesses, lymph scrotum, chyluria, and other disturbances of the lymphatic system. The connection between filariasis and elephantiasis is still a matter of argument among pathologists. When taken into the stomach of a mosquito the larve lose their cutic- ular sheaths. Within 24 hours they leave the alimentary tract, pass into the body cavity, then into the muscles of the thorax. In the muscles they become shortened to about half their original length and meanwhile 70 SANITARY ENTOMOLOGY increase to twice or more than twice their original thickness, developing into what is known as the sausage stage of general occurrence in the development of Filaria larve. Developing beyond this stage they increase rapidly in length, cast their skins at least once, and in one to two weeks after infection of the mosquito, or longer, according to temperature and the species of mosquito infected, they complete their larval development so far as the intermediate host is concerned, reaching a length finally about three to five times the length of the first-stage larve and a thickness about three or four times the original thickness. They leave the muscles, enter the body cavity, and migrate into various locations, posterior por- tions of the body, legs, palpi, but in greatest numbers into the labium. From the evidence afforded by the experiments of Noé (1900) with Dirofilaria immitis and additional experiments by Bancroft (1901), Lebredo (1904-1905), Fiilleborn (1908), and others, it has been con- cluded by analogy in the case of Filaria bancroftt that when an infected mosquito bites a human being the filaria larve bore through a thin portion of the labium known as Dutton’s membrane, and more rarely other thin portions of the proboscis, actively penetrate the skin of the individual attacked, and reach the lymphatic system where they complete their development to maturity. Both anopheline and culicine mosquitoes can serve as intermediate hosts of Filaria bancrofti including the following species (see also Chapter XVII): Anopheline mosquitoes Anopheles (Myzomyia) rossi Giles. & (Pyretophorus ) costalis Loew. i (Myzorhynchus) sinensis Wiedemann. s ss “ pediteniatus Leicester, er = barbirostris Van der Wulp. Culicine mosquitoes Culex pipiens Linnaeus Aedes argenteus Poirret (Stego- myta calopus Meigen) “ quinquefasciatus Say (fati- Aedes gracilis Leicester (Stego- gans Wiedemann) myia) Aedes scutellaris Walker (Culex “ — gelidus Theobald albopictus Skuse) “ sttiens Wiedemann Mansonioides uniformis Theobald Mansonioides annulipes Theobald Scutomyia albolineata Theobald Taeniorhynchus domesticus Lei- " cester RELATION OF INSECTS TO THE PARASITIC WORMS 71 Besides those named about a dozen other species of mosquitoes have been tested as hosts of Filaria bancrofti with negative results, or with results showing that the parasites would only develop imperfectly. Fleas, lice, and Stomoxys have been tested with negative results. Prophylaxis against Filaria bancrofti evidently consists in measures similar to those employed in malaria eradication with reference to mos- quito control. Filaria (Loa) loa (Cobbold, 1864) This parasite of man is a West African species. It has been brought to America in the slave trade but never established in the New World. The adults live usually in the subcutaneous connective tissue but have been found elsewhere in relation with the serous membranes of the ab- dominal and thoracic viscera. They move about from place to place and can change their location rather rapidly; for example, one of these worms has been seen to cross the bridge of the nose beneath the skin within a period of an hour or two. In their progress beneath the skin in various parts of the body they give rise to transient edematous areas known as Calabar swellings. The larvae produced by the females enter the blood stream where they are found in the peripheral vessels during the day time, contrary to the habits of the larvae of Filaria bancrofti. Because of this characteristic periodicity of the larvae, Filaria loa has been also named F’. diuwrna. The larvae of F. loa are provided with a sheath relatively much longer than that of the larvae of F. bancrofti. Experiments with various anopheline and culicine mosquitoes, and Glossina palpalis have given negative results as to the possibility of these insects acting as intermediate hosts. From Leiper’s (1913) researches, it would appear that a species of Chrysops (probably C. dimidiata or C. longicornis) acts as the intermediate host of Filaria loa, the larve undergoing their development in the salivary glands of the insect. Ac- cording to Ringenbach and Guyomarc’h (1914), the intermediate host in the Congo is Chrysops centurionis. Kleine (1915) in West Africa found 82 out of 600 Chrysops examined. to be infested with larval nematodes which he took to be the larvae of F’. Joa though he does not give sufficient evidence to support his claims. Filaria demarquayi Manson, 1895 This parasite, generally considered identical with Filaria juncea and F. ozzardi, occurs in man in the West Indies and in British Guiana. The adult has been found in the mesentery and under the peritoneum of the abdominal wall. The first-stage larvae occur in the blood stream. Their appearance in the circulation is not periodic. According to Low (1902) 72 SANITARY ENTOMOLOGY the larvae can be developed to the so-called “sausage” stage in Aedes argenteus (Stegomyia calopus). Experiments with Anopheles albimanus (albipes), Culex taeniatus, C. quinquefasciatus (fatigans), and other mosquitoes, fleas, and ticks failed to result in any development of the larvae. Fiilleborn (1908) was able to develop the larvae to the sausage stage in Anopheles maculipennis and Aedes argenteus (Stegomyia calo- pus), but no development occurred in the tick, Ornithodoros moubata. Further investigations are necessary to determine what insects serve as intermediate hosts for F. demarquayi. Filaria philippinensis Ashburn and Craig, 1906 The adult stage of this parasite of man is unknown. The first-stage larvae occurring in the blood of man are morphologically identical with those of Filaria bancrofti. Unlike the latter, however, they show no periodicity. Ashburn and Craig (1907) have shown that the larvae will undergo development in mosquitoes, Culex quinquefasciatus (fatigans). similar to that of the larvae of F. bancrofti. It is questionable whether F. philippinensis should be recognized as a distinct species. Filaria tucumana Biglieri and Ardoz, 1917 This species, the adults of which are unknown, is based on microfilarie found frequently in the blood of human beings in Argentina. It appears to be comparatively harmless. Biglieri and Ardoz (1917) conclude that mosquitoes act as intermediate hosts and apparently consider Aedes argenteus (Stegomyia calopus) the most important vector, though defi- nite proof of this has not been, obtained. Filaria cypselie Annett, Dutton and Elliott, 1901 The adult stage of Filaria: cypseli occurs in the subcutaneous tissue of the head of the swift, Cypselus affinis, also beneath the subcranial fascia. The embryos or first-stage larvae occur in the lymph and rarely in the peripheral blood of infested birds. Dutton (1905) has described various larval stages of the parasite which he finds in an undetermined’ species of bird-louse belonging to the subfamily Leiothinae that occurs on swifts. The first-stage larva as it is found in the blood of the bird and the stomach of the louse is provided with a sheath as in various other species of Filaria. This sheath is lost and the larva probably soon penetrates the stomach wall. The next stage of the parasite is found in the fat-body of the louse as are two later stages described by Dutton. The last stage of development seen by him is found free in the body RELATION OF INSECTS TO THE PARASITIC WORMS 3 cavity and this is probably the stage in which the parasite is trans- ferred to the bird; whether as a result of ingestion of the louse by the swift, or as a result of the active migration of the worm from the louse while the insect is engaged in biting, has not been determined. Filaria martis Gmelin, 1790 Filaria martis (or Filaria quadrispina) according to various writers occurs in its adult stage beneath the skin and in the abdominal and thoracic cavities of Mustela foina. Baldasseroni (1909) has found filaria embryos in the intestine of ticks (Ivodes ricinus) taken from a marten harboring the adult nematode, and he suggests that ticks may act as intermediate hosts. As in the case of Acanthocheilonema grasst, further evidence is necessary before ticks can be considered to play a part in the life history of Filaria martis. Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911 This nematode, sometimes erroneously listed as a parasite of man, lives in the right side of the heart and pulmonary artery of the dog. The larvae are found in the circulation, most numerous at night as in the case of Filaria bancroftt, As would be expected from the location of the adult parasite it may give rise to serious symptoms, and affected dogs commonly succumb to the disturbances which it causes. It is a troublesome parasite among hunting dogs in the Southern United States. Noé (1900) showed that the larvae of this nematode continue their de- velopment in certain species of mosquitoes when sucked up with the blood of infested dogs. In 24 to 36 hours after reaching the stomach of the mosquito the larvae pass into the Malpighian tubules. They undergo a certain growth and development in this location, and 11 or 12 days after reaching the mosquito they break out of the tubules, enter the body cavity, and migrate to the labium. From the labium of the mosquito they reach their final host, the dog, in the same manner as F. bancrofti reaches its human host, namely, by breaking through thin portions of the cuticle of the labium at the time the mosquito is engaged in biting its victim and then penetrate the skin, finally migrating to the heart. Mosquitoes infested with the larve of D. immitis are commonly killed by the parasites owing to their destructive action on the Malpighian tubules, Noé having observed that only about half the mosquitoes that become infested survive. In Italy the common intermediate hosts appear to be Anopheles maculipennis, A. bifurcatus, A. (Myzorhynchus) sinensis pseudopictus, and A. (Myzomyia) superpictus among anophelines ; culi- cines, according to Noé such as Culex penicillaris, C. malariae, and ex- ceptionally C. pipiens, can also act as intermediate hosts. 74 SANITARY ENTOMOLOGY Dirofilaria repens, Railliet and Henry, 1911 In the adult stage this nematode, which is a very similar parasite to D. immitis, occurs in the subcutaneous connective tissue of the dog. Its larvae enter the blood stream whence they are liable to be ingested by blood-sucking insects. According to Bernard and Bauche (1913) the yellow fever mosquito Aedes argenteus (Stegomyia calopus) acts as the intermediate host. These investigators while admitting that other species of mosquitoes might act as intermediate hosts of D. repens, found that A. argenteus best fulfilled the natural conditions for the transmission of the parasite, and their experiments were carried out with this species of mosquito. They followed the various stages in the development of the larval nematodes in mosquitoes fed experimentally upon infested dogs. About 2 days after the mosquito has been fed the nematode larvae leave the lumen of the alimentary tract and penetrate into the Malpighian tubules where they undergo most of their growth and development. By the eighth day the larvae may be found in some cases to have migrated into the body cavity and thoracic muscles and the last stage of develop- ment in mosquitoes may be found in the proboscis as early as the ninth day. Six young dogs (10 days old) were submitted to the bites of A. argenteus (fed 10 to 15 days previously on infected dogs) every morn- ing for fifteen days. Six young dogs of the same age were kept as con- trols, not exposed to mosquito bites. The bitten dogs all died within thirty days. Ecchymotic spots were found beneath the skin at the points of the mosquito bites, but no filarias were discovered. The other dogs all survived the experiment. Under natural conditions the youngest dogs found infested with D. repens by Bernard and Bauche were at least a year old, hence the writers conclude that the development of the parasite is very slow. Although they did not succeed in completing their experi- ments by recovering the adult stage of the parasite in dogs, following bites by infected mosquitoes, it appears safe to conclude that D. repens is transmitted by mosquitoes in a manner similar to that in which D. immitis is transmitted. Acanthocheilonema perstans (Manson, 1891) Railliet, Henry and Langeron, 1912 This parasite occurs in man in tropical Africa and British Guiana, the adults in the intraperitoneal connective tissue and fatty tissue of the abdominal viscera and pericardium, and the first-stage larvae in the blood stream. The larvae exhibit no periodicity in their appearance in the circulation, the name perstans having reference to this fact. Christy (1903) has suggested that Ornithodoros moubata may act as RELATION OF INSECTS TO THE PARASITIC WORMS 5 the intermediate host of Acanthocheilonema perstans. Wellman (1907) has reported that the larvae of this parasite are taken up by Ornithodoros moubata and according to his statements develop very slowly in this tick, advanced stages not being found until more than two months after infection of the tick. The suggestion made by Feldmann (1905), influ- enced by Bastian (1904), that the larvae of A. perstans may pass out of the body of the tick with its eggs into bananas and afterwards being swallowed with this fruit by human beings is a mode of infection which requires no consideration as a possibility without more supporting evi- dence than has yet been advanced. Hodges (1902) observed Filaria larvae in the thoracic muscles of the mosquitoes, Panoplites sp. and Aedes argenteus (Stegomyia calopus), three days after they had been fed on perstans blood. Low (1903) was able in one case to obtain development of perstans larvae to the sausage stage in a mosquito (Chrysoconops fuscopennatus). Fiilleborn (1908, 1913) obtained a similar development in Anopheles maculipennis. Fiille- born and Low obtained negative results with various species of mosquitoes, sand fleas, lice and simuliids. Acanthocheilonema grassii (Noé, 1907) Railliet, Henry and Langeron, 1912 The adults of this nematode occur in the subcutaneous and intermus- cular connective tissue and peritoneal cavity of the dog. The larvae produced by the females are unusually large, about twice as long and thick as the average filaria larva, and according to Noé (1907, 1908) do not pass into the blood stream as is generally the case among the filarias. Noé assumed that the larve are restricted to the lymphatic system, and accordingly concluded that the intermediate host would most likely be a tick or similar slow feeding ectoparasite. In fact he found nematode larvae corresponding to those of A. grassii in Rhipicephalus sanguimeus, a tick of common occurrence in regions where the dogs are infested with the nematode in question. Furthermore he states that all of the ticks attached to dogs infested with the nematode become infested with the larval worms. Additional evidence that R. sanguineus acts as the intermediate host is that the larvae in the ticks undergo growth and development, at least one molting period having been observed between successive stages. As R. sanguineus is a tick which falls to the ground to transform from the nymphal to the adult stage, the necessary opportunity is afforded for the transmission of A. grassii from one dog to another. Noé remarks that the nymph of this tick ingests large quantities of lymph. The larval nematodes taken in with the ingested lymph penetrate the intestinal wall into the body cavity where they undergo the develop- 76 SANITARY ENTOMOLOGY ment necessary before they are ready to be returned to the definitive host, after transformation of the nymphal tick to the adult stage. Noé be- lieves that the dog becomes infected during the initial phase of attach- ment of the adult. He also suggests that adult males which, unlike adult females, may pass from one host to another are capable of acquiring infection from one dog and transferring it to another. He has found as many as 22 larvae of A. grassii in one male tick. Noé is of the opinion that the larvae escape through thin portions of the cuticle of the mouth parts of the tick and thus reach the final host in a way similar to that followed by the larvae of D. immitis and other filarias trans- mitted by mosquitoes. It is of interest to note that Grassi and (dishariacis (1890) found larval nematodes in Rhipicephalus siculus (—=R. sanguineus) which they identified as the larve of Filaria recondita (—=Acanthocheilonema recon- ditum). Noé thinks that these larvae may have been A. grassii rather than A. reconditum. Evidently further investigations into the life history of A. grassii are necessary before ticks can be accepted as the intermediate host of this parasite. Acanthocheilonema reconditum (Grassi, 1890) Railliet, Henry and Langeron, 1912 This nematode is a parasite of the dog and in the adult stage has been collected from adipose tissue in the neighborhood of the kidney. Accord- ing to Grassi and Calandruccio (1890) the first-stage larvae occur in the © blood stream, and are the so-called Haematozoa of Lewis which have been seen by many observers, first by Gruby and Delafond (1843), after- wards by Lewis and others. Apparently, however, the larvae seen in the blood of dogs by Grassi and Calandruccio as well as those known as Lewis’s Haematozoa are in reality the larvae of Dirofilaria repens. Grassi and Calandruccio describe various stages of nematode larvae found in fleas (Ctenocephalus canis, C. felis, and Pulex irritans) and in a tick (Rhipicephalus siculus=R. sanguineus) as developmental stages in the life history of A. reconditum. According to Noé (1907, 1908), the larvae found in R. sanguineus by Grassi and Calandruccio were probably those of Acanthocheilonema grassii. Owing to the confusion existing with reference to the identity of the parasite that Grassi and Calandruccio studied, the species to which the larval nematodes observed in fleas belong, is uncertain. Grassi and Calan- druccio’s experiments can not be considered conclusive so far as con- cerns the life history of A. reconditum. RELATION OF INSECTS TO THE PARASITIC WORMS "7 Setaria labiato-papillosa (Alessandrini, 1838) Railliet and Henry, 1911 The adults of this nematode are common parasites in the peritoneal cavity of cattle in various parts of the world including the United States. The larvae enter the blood stream, and Nod (1903) identifies certain larval nematodes found in Stomorys calcitrans as belonging to this species. That this fly actually serves as the intermediate host, however, remains to be proved. The possibility is not excluded that Nod mistook Habronema larve for the larve of §. labiato-papillosa. Oncocerca About twelve species of this genius have been described. Onco- cerca voloulus in the adult stage occurs in nodular tumors beneath the skin of man in Africa. Oncocerca caecutiens is found in subcutaneous nodules on the head among natives living at a certain altitude on the west coast of Guatemala and is the cause of so-called “Coast erysipelas.” O. gibsoni causes worm nodules in the brisket and other locations in cattle in Australia. T'wo species occur in cattle in the United States: one undetermined species is found in relation with the ligaments of the legs and neck, the other (0. lienalis) is found in the gastrosplenic liga- ment. Oncocerca larvae have not been found in the blood stream but may be recovered from the lymph spaces in the neighborhood of the adult worms. The intermediate hosts of these nematodes are unknown but biting insects have been suspected. The results of experiments have been nega- tive. Brumpt (1903) has suggested the possibility that Glossina palpalis acts as intermediate host of O. volvulus. Robles (1919) suggests that two species of Simulium (close to S. dimelli and S. samboni) may be involved as vectors of O. caecutiens in view of the fact that these flies are most numerous in the places where the largest number of cases of Oncocerca occur. Furthermore these species of flies are absent in lower altitudes corresponding with the absence of Oncocerca. . 3. Other Nematodes Different investigators have recorded the occurrence of larval nema- todes of unknown species in various insects. Usually these have been very poorly described and it is questionable in many cases whether if found again they could be recognized as the same forms. Some of them may be the larval forms of nematodes whose adults are already known as parasites of higher animals. Among such larvae of uncertain _ identity may be mentioned Filaria geotrupis in the abdominal cavity . 78 SANITARY ENTOMOLOGY of Geotrupes stercorarius (possibly the larva of Physocephalus sexala- tus), Filaria ephemeridarum in the abdominal cavity of the larvae of Ephemera vulgata and Oligoneuria rhenana, Filara rytipleuritis (of Magalhaes, 1900, not Deslongchamps, 1824) in the abdominal cavity of Periplaneta americana (possibly a Gongylonema according to Seurat), Filaria stomoxeos in Stomoaxys calcitrans (possibly the larva of Hab- ronema microstoma), Mastophorus echiurus, and Cephalacanthus mona- canthus in Tenebrio molitor (probably larvae of Protospirura muris), Mastophorus globocaudatus and Cephalacanthus triacanthus in Geotrupes stercorarius (possibly larvae of Physocephalus sexalatus). 4. Mermithidae These worms which resemble the nematodes and are usually grouped with them are not known to be of importance in medical zoology. One species, of uncertain identity, is of interest, however, as it is the so-called “cabbage snake” whose presence among the leaves of cabbage has alarmed people who have encountered it. This worm, like others of the same family, undoubtedly passes through a portion of its development in the body of an insect, probably one of the common caterpillars that attack cabbage. Similar worms have been found in apples. GORDIACEA OR HORSE-HAIR WORMS The Gordiacea or horse-hair worms (as which they are popularly known from the superstitious belief that they are animated horse hairs) are of medical interest because several species have been recorded as parasites of man. They gain entrance to the alimentary tract by being swallowed in drinking water. The adults are of not uncommon occur- | rence in springs and other surface waters. When swallowed by human beings they are usually soon vomited up but they have in some cases apparently survived in the intestine for several months before they were finally expelled. In some species, and probably in all, insects serve as hosts for the larval stages. The adults deposit their eggs in the water in which they live. The larvae hatching from the eggs enter the bodies of insects such as grasshoppers (as for example, in the case of Gordius robustus) or crickets (as for example, in the case of Paragordius varius ) or in the case of other species they may enter aquatic insect larvae, which may later be devoured by carnivorous water insects. In the latter the worms undergo their development until they have reached or ap- proached maturity when they burst out of the infested insect and escape into the water. The following species of Gordiacea have been recorded as accidental parasites of man: Gordius aquaticus, G. chilensis, Para- RELATION OF INSECTS TO THE PARASITIC WORMS ‘9 gordius varius (a common American species), Paragordius tricuspidatus, Parachordodes tolusanus, Parachordodes violaceus, Parachordodes pus- tulosus, and Chordodes alpestris. ACANTHOCEPHALA OR THORN-HEADED WORMS This highly specialized group of parasites, commonly classified in the Nemathelminthes, with which it has little in common beyond a superficial resemblance in the general shape of the body, has been but little studied. Most of the known species are parasitic in birds. Macracanthorhynchus hirudinaceus (Pallas, 1781) Travassos, 1916 This worm in the adult stage (sometimes called the giant thorn- headed worm) is a common parasite of the intestine of the pig and is said to occur as a parasite of man along the River Volga. Its eggs pass out of the body of the host in the feces. Swallowed by certain insects [larvae of Melolontha melolontha, Cetonia aurata, Phyllophaga arcuata (Lach- nosterna), and Diloboderus abderus] the eggs hatch, and the larvae develop into an intermediate stage, which in turn completes its develop- ment to maturity when the infested grub is eaten by a pig. Moniliformis moniliformis (Bremser, 1819) Tyravassos, 1915 This parasite in its adult stage (sometimes called the beaded thorn- headed worm) is of common occurrence in the intestine of rats and other rodents in tropical and subtropical regions, and has been found in man in Italy. The life cycle is similar to that of the giant thorn-headed worm except for the difference in hosts. According to Grassi and Calandruccio (1888), Blaps mucronata acts as an intermediate host. According to Magalhaes (1898) and Seurat (1912), the usual intermediate host is a cockroach (Periplaneta americana). COMPENDIUM OF PARASITES ARRANGED ACCORDING TO INSECT HOSTS 2 Aphaniptera (Siphonaptera)—fleas Ceratophyllus fasciatus Bosc : Hymenolepis diminuta ? Hymenolepis nana Ctenocephalus canis Curtis ? Acanthocheilonema reconditum 2 The scientific names of the insects have been revised by the editor. 80 SANITARY ENTOMOLOGY Dipylidium caninum Hymenolepis diminuta Ctenocephalus felis Bouché ? Acanthocheilonema reconditum’ ? Dipylidium caninum Pulex irritans Linnaeus ? Acanthocheilonema reconditum Dipylidium caninum Hymenolepis dimimuta Xenopsylla cheopis Rothschild Hymenolepis diminuta ? Hymenolepis nana ? Protospirura muris Diptera—fiies Aedes argenteus Poirret (Stegomyia calopus Meigen) Acanthocheilonema perstans (incomplete development) Dirofilaria repens Filaria bancrofti Filaria demarquayi (incomplete development) ? Filaria tucumana Aedes gracilis Leicester (Stegomyia) Filaria bancrofti Aedes scutellaris Walker (Culex albopictus Skuse) Filaria bancrofti Anopheles barbirostris Van der Wulp (Myzorhynchus) Filaria bancrofti Anopheles bifurcatus Linnaeus Dirofilaria immitis Anopheles costalis Loew (Pyretophorus) Filaria bancrofti Anopheles maculipennis Meigen (claviger Fabricius) Acanthocheilonema perstans (incomplete development) Dirofilaria immitis Filaria demarquayi (incomplete development) Trematode RELATION OF INSECTS TO THE PARASITIC WORMS Anopheles rossi Giles (Myzomyia) Trematode Filaria bancrofti Anopheles sinensis Wiedemann (Myzorhynchus) Filaria bancrofti Anopheles sinensis peditaeniatus Leicester (Myzorhynchus) Filaria bancrofti Anopheles sinensis pseudopictus Grassi (Myzorhynchus) Dirofilaria immitis Anopheles superpictus Grassi (Myzomyia) Dirofilaria immitis Chironomus plumosus Linnaeus Lecithodendrium ascidia Chrysoconops fuscopennatus (Theobald) (‘Taeniorhynchus) Acanthocheilonema perstans (incomplete development) Chrysops spp. Filaria (Loa) loa ? Chrysops centurionis Austen Filaria (Loa) loa ? Chrysops dimidiata Van der Wulp Filaria (Loa) loa ? Chrysops longicornis Macquart Filaria (Loa) loa Culex gelidus Theobald Filaria bancrofti a Culex malariae Grassi Dirofilaria immitis Culex penicillaris Rondani Dirofilaria immitis 81 SANITARY ENTOMOLOGY Culex pipiens Linnaeus Dirofilaria immitis Filaria bancrofti Culex quinquefasciatus Say (skusei Giles) (fatigans Wiedemann) Filaria bancrofti Culex sitiens Wiedemann Filaria bancrofti Mansonioides annulipes Theobald Filaria bancrofti Mansonioides uniformis Theobald Filaria bancrofti Musca domestica Linnaeus Choanotaenia infundibulum Habronema muscae Habronema microstoma Habronema megastoma ? Davainea cesticillus ? Davainea tetragona Panoplites sp. Acanthocheilonema perstans (incomplete development) Scutomyia albolineata Theobald Filaria bancrofti Stomoxys calcitrans Linnaeus Filaria stomoxeos Habronema microstoma ? Habronema muscae ? Setaria labiato-papillosa ? Hymenolepis carioca Taeniorhynchus domesticus Leicester Filaria bancrofti Neuroptera Sialis lutaria (Linnaeus) Trematode RELATION OF INSECTS TO THE PARASITIC WORMS Trichoptera—hairy-winged insects Anabolia nervosa (Leach) Curtis Allocreadium isoporum Opisthioglyphe rastellus Chaetopteryx villosa (Fabricius) Allocreadium isoporum Drusus trifidus McLachlan Trematode Limnophilus flavicornis (Fabricius) Opisthioglyphe rastellus Limnophilus griseus (Linnaeus) Opisthioglyphe rastellus Limnophilus lunatus (Curtis) Opisthioglyphe rastellus Limnophilus rhombicus (Linnaeus) Opisthioglyphe rastellus Mystacides nigra (Linnaeus) Trematode Notidobia ciliaris (Linnaeus) Trematode Phryganea grandis Trematode Phryganea sp. Lecithodendrium chilostomum Rhyacophila nubila Zetterstedt Trematode Lepidoptera—toths, butterflies Asopia farinalis (Linnaeus) Hymenolepis dimimuta Nymphula nymphaeata (Linnaeus) (Hydrocampa) Trematode 83 84 SANITARY ENTOMOLOGY Coleoptera—beetles Akis goryi (Solier) Spirocerca sanguinolenta Spirura gastrophila Akis spinosa (Linnaeus) Hymenolepis diminuta Aphodius rufus (Moll) var. castaneus Marsh Arduenna strongylina Aphodius coloradensis Horn Gongylonema scutatum Aphodius femoralis Say Gongylonema scutatum Aphodius fimetarius Linnaeus Gongylonema scutatum Aphodius granarius Linnaeus ‘Gongylonema scutatwm Aphodius vittatus Say Gongylonema scutatum Blaps appendiculata Gongylonema sp. (G. scutatwm according to Seurat) Blaps sp. Gongylonema brevispiculum Blaps sp. (near appendiculata ) Spirura gastrophila Gongylonema sp. (G. scutatum according to Seurat) Blaps emondi Gongylonema sp. (G. scutatum according to Seurat) Blaps mucronata Latreille Moniliformis moniliformis Blaps strauchi Reiche Spirura gastrophila Gongylonema sp. (G. scutatum according to Seurat) RELATION OF INSECTS TO THE PARASITIC WORMS Cetonia aurata (Linnaeus) Macracanthorhynchus hirudinaceus Copris hispanus (Linnaeus) Spirocerca sanguinolenta Diloboderus abderus Sturm Macracanthorhynchus hirudinaceus Geotrupes douei Gory ? Gongylonema mucronatum Spirocerca sanguinolenta Physocephalus sexalatus Geotrupes stercorarius (Linnaeus) Cephalacanthus triacanthus Filaria geotrupis Mastophorus globocaudatus ? Physocephalus sexalatus Gymnopleurus mopsus (Pallas) ? Gongylonema mucronatum Gymnopleurus sturmi Mac Leay ? Gongylonema mucronatum Spirocerca sanguimolenta Ilybius fuliginosus (Fabricius) Haplometra cylindracea Melolontha melolontha Linneus (vulgaris Fabricius) Macracanthorhynchus hirudinaceus Chironitis irroratus Rossi (Onitis) ? Gongylonema mucronatum Onthophagus spp. Arduenna strongylina Spirura gastrophila Onthophagus bedeli Neitt. ? Gongylonema mucronatum Physocephalus sexalatus 85 86 SANITARY ENTOMOLOGY Onthophagus hecate Panzer Gongylonema scutatum Onthophagus nebulosus Reiche Physocephalus sexalatus Onthophagus pennsylvanicus Harold Gongylonema scutatum Phyllophaga arcuata Smith (Lachnosterna) Macracanthorhynchus hirudinaceus Scarabaeus (Ateuchus) sacer Linnaeus ? Gongylonema mucronatum Physocephalus sexalatus Spirocerca sanguinolenta Scarabacus (Ateuchetus) variolosus Fabricius Physocephalus sexalatus ? Spirocerca sanguinolenta Scaurus striatus Fabricius Hymenolepis diminuta Tenebrio molitor Linnaeus Cephalacanthus monacanthus Gongylonema neoplasticum Hymenolepis diminuta ? Hymenolepis microstoma Mastophorus echiurus Protospirura muris Water beetles Pleurogenes claviger Pleurogenes medians Prosotocus confusus Mallophaga—bird lice Leiothinae (? genus ? species) Filaria cypseli Trichodectes latus Nitzsch (canis DeGeer) Dipylidium caninum RELATION OF INSECTS TO THE PARASITIC WORMS Isoptera—termites Hodotermes pretoriensis Fuller Filaria aallinarum Odonata—dragonflies Aeschna sp. Prosotocus confusus Agrion sp. Gorgodera pagenstecheri Gorgodera varsoviensis Pleurogenes medians Calopteryx virgo (Linnaeus) Halipegus ovocaudatus Pnewmonoeces similis Cordulia sp. Prosotocus confusus Epitheca spp. Gorgodera cygnoides Gorgodera pagenstecheri Gorgodera varsoviensis Plectoptera—mayfiies Cleon dipterum (Linnaeus) Stephens ? Opisthioglyphe rastellus Ephemera vulgata Linnaeus Allocreadium isoporum Filaria ephemeridarum ? Opisthioglyphe rastellus Ephemeridae Lecithodendrium ascidia Oligoneuria rhenana Imhoff Filaria ephemeridarum 87 88 SANITARY ENTOMOLOGY Plecoptera—stoneflies Perlidae Lecithodendriwm ascidia Trematode Orthoptera—cockroaches, etc. Blattella germanica (Linnaeus) Caudell Gongylonema neoplasticum Gongylonema scutatum (experimental infection) Periplaneta americana (Linnaeus) Burmeister Filaria rytipleuritis of Magalhies, 1900 Gongylonema neoplasticum Moniliformis moniliformis Blatta orientalis Linnaeus Gongylonema neoplasticum ? Spirocerca sanguinolenta Spirura gastrophila Dermaptera—earwigs Anisolabis annulipes Lucas Hymenolepis diminuta Myriapoda—nmillipedes, centipedes ? Fontaria virginiensis (Drury) Hymenolepis diminuta Glomeris limbata Tapeworm larvae Julus sp. Hymenolepis diminuta Julus guttulatus Nematode larva Acarina—ticks, mites ® Ixodes ricinus (Linnaeus) Latreille ? Filaria martis 3 Included in list because of their similarity to insects. RELATION OF INSECTS TO THE PARASITIC WORMS 89 Ornithodoros moubata (Murray) ‘'? Acanthocheilonema perstans Rhipicephalus sanguineus (Latreille) ? Acanthocheilonema grassii ? Acanthocheilonema reconditwm Isopoda—sowbugs * Porcellio laevis Latreille ? Acuaria spiralis LIST OF REFERENCES Ackert, James E. 1918.—On the life cycle of the fowl cestode, Davainea cesticillus (Molin). (Preliminary communication.) Jour. Parasit. Ur- bana, IIl., Vol. 5, No. 1, Sept., pp. 41-43, pl. 5, figs. 1-4. 1919.—On the life history of Davainea tetragona (Molin), a fowl tapeworm. Jour. Parasit., Urbana, IIl., Vol. 6, No. 1, Sept., pp. 28-34. Ashburn, P. M., and Craig, Charles F. 1907.—Observations upon Filaria philippimensis and its development in the mosquito. Philippine Journ. Sci., vol. 2B, No. 1, Mar., pp. 1-14, pls. 1-7, figs. 1-26. Baldasseroni, Vincenzo. 1909.— ‘Ixodes ricinus” L. infetto da embrioni di Filaria. Bull. Soc. Entom. Ital., vol. 40, Nos. 3-4; pp. 171-174, Dec. 30. Bancroft, Thomas L. 1901.—Preliminary notes on the intermediate host of Filaria immitis Leidy. Journ. Trop. Med. Lond., vol. 4, Oct. 15, pp. 347-349. Bastian, H. Charlton. 1904.—Note on the probable mode of infection of the so-called Filaria perstans, and on the probability that this organism really belongs to the genus Tylenchus (Bastian). Lancet, vol. 166, No. 4196, vol. 1, No. 5, Jan. 30, pp. 286-287, figs. 1-3, Bernard, P. Noél, and Bauche, J 1913.—Conditions de propagation de la filariose sous-cutanée du chien. Stegomyia fasciata hédte intermediaire de Dirofilaria repens. Bull. Soc. Path. Exot., vol. 6, No. 1, Jan. 8, pp. 89-99, sie 1-9. *Included in list because of their similarity to insects. 90 SANITARY ENTOMOLOGY Biglieri, R., and Ardoz, J. M. 1917.—Contribucién al estudio de una nueva filariosis humana encon- trada en la Reptblica Argentina (Tucumdn ), ocasionada por la “Filaria tucumana.” 1. Confer. Soc. sud-am. de hig. [etc.], Buenos Aires Sept. 17-24, 1916, pp. 403-422. Brumpt, Emile. 1903.—Sur réle des mouches tsé-tsé en pathologie exotique. Compt. Rend. Soe. Biol., vol. 55, No. 34, Dec. 4, pp. 1496-1498. Bull, Lionel B. 1916.—A granulomatous affection of the horse—Habronemic granu- lomata (cutaneous habronemiasis of Railliet). Journ. Comp. Path. and Therap., vol. 29, No. 3, Sept. 30, pp. 187-199, figs. 1-5. 1919.—A contribution to the study of habronemiasis: A clinical, pathological, and experimental investigation of a granulomat- ous condition of the horse-habronemic granuloma. pp. 85-141, pls. 13-15, figs. 1-8. [Reprint from Tr. Roy. Soc. South Australia, v. 43.] Christy, Cuthbert. 1903.—The distribution of sleeping sickness, Filaria perstans, etc., in East Equatorial Africa. (Preliminary report dated Oct. 31, 1902). Roy. Soc. Rep. Sleep.-Sick. Comm., No. 2, Nov., pp. 3-8, 3 maps. De Magalhies, Pedro Severiano, 1898.—Notes d’helminthologie brésilienne. [5. note] Arch, Parasitol., vol. 1, No. 3, July, pp. 361-368, figs. 1-4. 1900.—Notes d’helminthologie brésilienne. [8. note] Arch. Parasitol. vol. 8, No. 1, May 15, pp. 34-69, figs. 1-25. Descazeaux, J. , 1915.—Contribution 4 l’étude de Il’ “esponja” ou plaies d’été des équidés du Brésil. (Rapport de Railliet, 17 juin). Bull. Soc. Centr. de Méd. Vét., vol. 69, Jan. 30-Sept. 30, pp. 468-486, figs. 1-3. Deslongchamps, Eugéne Eudes. 1824.—Filaire. Filaira, Encycl. Méthodique, vol. 2, pp. 391-397. RELATION OF INSECTS TO THE PARASITIC WORMS 91 Dutton, J. Everett. 1905.—The intermediary host of Filaria eupiets (Annett, Dutton, El- liott); the Filaria of the African swift, Cypselus affinis. Thompson Yates & Johnston Lab. Rep., Lond., n. s., vol. 6, No. 1, Jan., pp. 137-147, pl. 5, figs. i-x. Feldmann. 1905.—Ueber Filaria perstans im Bezirk Bukoba. Arch. f. Schiffs- u Tropen-Hyg., vol. 9, No. 2, Feb., pp. 62-65, 2 pls. Fibiger, Johannes, and Ditlevsen, Hjalmar. 1914.—Contributions to the biology and morphology of Spiroptera (Gongylonema) neoplastica n. s. Mindeskr. Japetus Steen- strups Fodsel, 2. Halvbind, 28 pp., figs. 1-3, pls. 1-4, figs. 1-32. Fiilleborn, Friedrich. 1908.—Ueber Versuche an Hundefilarien und deren Ubertragung durch Miicken. Beihefte (8) z. Arch. f. Schiffs- u. Tropen-Hyg., vol. 12, Nov., pp. 313-351 (43 pp.), figs. 1-6, pls. 1-4, figs. 1-38. 1908.—Untersuchungen an menschlichen Filarien und deren Uber- tragung auf Stechmiicken. Beihefte (9) z. Arch. f. Schiffs- u Tropen-Hygr., vol. 12, Nov., pp. 357-388 (36 pp.), figs. 1-3, pis. 1-7, figs. 1-132. 1913.—Die Filarien des Menschen. MHandb. d. path. Mikroorganism. (Kolle & Wassermann), Jena, 2. Aufl., vol. 8, pp. 185-344, figs. 1-41, pls. 1-6. Galeb, Osman. 1878.—Observations et expériences sur les migrations du Filaria rytipleurites, parasite des blattes et des rats. Compt. Rend. Acad. Sc., vol. 87, No. 2, July 8, pp. 75-77. Grassi, Giovanni Battista. 1887.—Entwickelungscyklus der Tania nana, Dritte préliminarnote. Centralbl. f. Bakteriol. (etc.), Jena, 1. Jahr., vol. 2, No. 11, pp. 305-312, 1888.—Ciclo evolutivo della Spiroptera (Filaria) sanguinolenta. Gior. di Anat., Fisiol. e Patol. d. Animali, vol. 20, No. 2, Mar.-Apr., pp. 99-101. Grassi, Giovanni Battista, and Calandruccio, Salvatore. 1888.—Ueber einen Echimorhynchus, welcher auch im Menschen para- sitirt und dessen Zwischenwirth ein Blaps ist. Centralbl. f. 92 SANITARY ENTOMOLOGY Bakteriol. (etc.), Jena, 2. Jahr., vol. 3, No. 17, pp. 521-525, figs. 1-7. 1890.—Ueber Haematozoon Lewis. Entwickelungscyklus einer Filaria (Filaria recondita Grassi) des Hundes. Centralbl. f. Bakteriol. (etc.), Jena, vol. 7, No. 1, Jan. 2, pp. 18-26, figs. 1-16. Grassi, Giovanni Battista, and Rovelli, Giuseppe. 1888.—Intorno allo sviluppo cestodi. Nota preliminare. Atti R. Accad. d. Lincei, Roma, Rendic., an. 285, 4. s., vol. 4, 1. semestre, No. 12, June 3, pp. 700-702. 1888.—Bandwiirmerentwickelung. Centralbl. f. Bakteriol. (etc.), Jena, 2. Jahr, vol. 3, No. 6, p. 173. 1889.—Sviluppo del cisticerco e del cisticercoide. Nota preliminare. Atti R. Accad. d. Lincei, Roma, Rendic., an. 286, 4. s., vol. 5, 1. semestre, No. 3, Feb. 3, pp. 165-174, figs. 1-4. 1892.—Ricerche embriologiche sui cestodi, Atti Accad. Giornia di Sc. Nat. in Catania (1891-92), an. 68, 4. s., vol. 4, 2, mem., 108 pp-, & pls. Gruby, David, and Delafond, Henri-Mamert-Onesius, 1843.—Note sur une altération vermineuse du sang d’un chien déter- minée par un grand nombre d’hématozoaires du genre filaire. Compt. Rend. Acad. Sc., vol. 16, No. 6, Feb. 6, pp. 325-326. Guberlet, John E. 1916.—Morphology of adult and larval cestodes from poultry. Trans. Am. Micr. Soc., vol. 35, No. 1, Jan., pp. 23-44, pls. 5-8, figs. 1-30. 1919.—On the life history of the chicken cestode, Hymenolepis carioca (Magalhaes). Journ. Parasit., vol. 6, No. 1, Sept., pp. 35-38, pl. 4, figs. 1-6. Hill, Gerald F. 1918.—Relationship of insects to parasitic diseases in stock. Pp. 11- 107, pls. 2-8, figs. 1-49A. 8°. Melbourne. [Reprint from Proc. Roy. Soc. Victoria, new ser., v. 31, pt. 1.] Hodges, Aubrey. 1902.—Sleeping-sickness and Filaria perstans in Busoga and its neigh- borhood, Uganda Protectorate. Journ. Trop. Med., vol. 5, No. 19, Oct. 1, pp. 293-300, 1 map, 1 pl., figs. 1-2. Johnston, T. Harvey. ; 1913.—Notes on some Entozoa. Proc. Roy. Soc. Queensland, vol. 24, pp. 63-91, pls. 2-5, figs. 1-45. (Advance separate issued Nov. 1, 19129). RELATION OF INSECTS TO THE PARASITIC WORMS 93 Joyeux, Ch. ‘ 1916.—Sur le cycle évolutif de quelques cestodes. Note préliminaire. Bull. Soc. Path. Exot., vol. 9, No. 8, Oct. 11, pp. 578-583. Kleine, F. K. 1915.—Die Ubertragung von Filarien durch Chrysops. Zeitschy. f. Hyg. u. Infektionskrankh., vol. 80, No. 3, Oct. 26, pp. 345-549. Lebredo, Mario G. 1904.—Filariasis. Nota preliminar deducida de experiencias practicas, que demuestran el sitio por donde la Filaria noctwrna abandona el Culex pipiens infectado. Rev. Med. Trop., Habana, vol. 5, No. 11, Nov., pp. 171-172. 1905.—Metamorphosis of Filaria in the body of the mosquito (Culex pipiens). Journ. Infect. Dis., Suppl. (1), May, pp. 332- 352, pls. 1-3, figs. 1-16. Leiper, Robert T. 1913.—[Metamorphosis of Filaria loa.] ['Telegram to London School Trop. Med., Dec. 27, 1912]. Lancet, No. 4662, vol. 184, vol. 1, No. 1, Jan. 4, p. 51. Leuckart, Karl Georg Friedrich Rudolph. 1867.—Die menschlichen Parasiten und die von ihnen herriihrenden Krankheiten. Ein Hand- und Lehrbuch fiir Naturforscher und Aerzte. Vol. 2, 1. Lief., vi, 256 pp., 158 figs. Leipzig & Heidel- berg. Low, George C. 1902.—Notes on Filaria demarquaii. Brit. Med. Journ., No. 2148, vol. 1, Jan. 25, pp. 196-197. 1903.—Filaria perstans. Brit. Med. Journ., No. 2204, vol. 1, Mar. 28, pp. 722-724, figs. 1-2. Manson, (Sir) Patrick. 1878.—On the development of Filaria sanguinis hominis, and on the mosquito considered as a nurse. Journ. Linn. Soc. Lond., Zool. (75), vol. 14, Aug. 31, pp. 304-311. Marchi, Pietro. 1867.—Monografia sulla storia genetica e sulla anatomia della Spiroptera obtusa Rud., 34 pp., 2 pls. fol. Torino. [ Advance separate from Mem. R. Accad. Sc. Torino, Cl. d. Sc. Fis., Mat. e Nat., 2. s., vol. 25, issued in 1871.] 94 SANITARY ENTOMOLOGY Melnikov, Nicolaus. 1869.—Ueber die Jugendzustinde der Tenia cucwmerina. Arch. f. Naturg., Berl., 35. Jahr., vol. 1, No. 1, pp. 62-70, pl. 3, figs. a-c. Nickerson, W. S. 1911.—An American intermediate host for Hymenolepis diminuta, Science, n. s., No. 842, vol. 33, Feb. 17, p. 271. Nicoll, W., and Minchin, E. A. 1911.—Two species of cysticercoids from the rat-flea (Ceratophyllus fasciatus). Proc. Zool. Soc. Lond., No. 1, Mar., pp. 9-13, figs. 1-2. Noé, Giovanni. 1900.—Propagazione delle filarie del sangue esclusivamente per mezzo della puntura della zanzare. 2. Nota preliminare, Atti R. Accad. d. Lincei, Rendic. Cl. di Sc. Fis., Mat. e Nat., an. 297, 5. s., vol. 9, 2. semestre, No. 12, Dec. 16, pp. 357-362, figs. 1-3. 1903.—Studi sul ciclo evolutivo della Filaria labiato-papillosa, Ales- sandrini. Nota preliminare. Atti R. Accad. d. Lincei, Rendic. Cl. di Sc. Fis., Mat. e Nat., an. 300, 5. s., vol. 12, 2 semestre, No. 9, Nov. 8, pp. 387-393. 1907.—La Filaria grassii, n. sp. e la Filaria recondita, Grassi. Nota preliminare. Atti R. Accad. d. Lincei, Rendic. Cl. di Se. Fis. Mat. e Nat., an. 304, 5. s., vol. 16, 2. semestre, No. 12, Dec. 15, pp. 806-810. 1908.—I ciclo evolutivo della Filaria grassii, mihi, 1907. Atti R. Accad, d. Lincei, Rendic. Cl. di Sc. Fis., Mat. e Nat., an. 305, 5. s., vol. 17, 1. semestre, No. 5, Mar. 1, pp. 282-293, figs. 1-4. Nuttall, George H. F. 1899.—On the réle of insects, arachnids, and myriapods as carriers in the spread of bacterial and parasitic diseases of man and animals. A critical and historical study. Johns Hopkins Hosp. Rep., Baltimore, vol. 8, Nos. 1-2, pp. 1-154, pls. 1-3. Piana, Giovanni Pietro. 1897.—Osservazioni sul Dispharagus nasutus Rud. dei polli e sulle larve nematoelmintiche delle mosche e dei porcellioni. Atti Soc. Ital. Sc. Nat. (etc.), Milano, vol. 36, No. 3-4. Feb., pp. 239-262, figs. 1-21. RELATION OF INSECTS TO THE PARASITIC WORMS 95 Ransom, Brayton H. 1911.—The life history of a parasitic nematode—Habronema muscae. Science n. s., No. 881, vol. 34, No. 17, pp. 690-692. 1913.—The life history of Habronema muscae (Carter), a parasite of the horse transmitted by the house fly. U.S. Dept. Agric., Bureau Animal Indust., Bull. 163, Apr. 3, pp. 1-36, figs. 1-41. Ransom, Brayton H., and Hall, Maurice C. 1915.—The life history of Gongylonema scutatum. Journ. Parasit., vol. 1, No. 3, Mar., p. 154. 1916.—The life history of Gongylonema scutatum. Journ. Parasit., vol. 2, No. 2, Dec., 1915, pp. 80-86. 1917.—A further note on the life history of Gongylonema scutatum. Journ. Parasit., vol. 3, No. 4, June, pp. 177-181. Ringenbach, J., and Guyomarc’h. 1914.—La filariose dans les régions de la nouvelle frontiére Congo- Cameroun. Observations sur la transmission de Microfilaria diurna et de Microfilaria perstans. Bull. Soc. Path. Exot., vol. 7, No. 7, July 8, pp. 619-626. Robles, R. 1919.—Onchocercose humaine au Guatémala produisant la cécité et “Vérysipéle du littoral” (erisipela de la costa). Bull. Soc. Path. Exot., vol. 12, No. 7, July 9, pp. 442-460, 2 maps, figs. 1-6. Seurat, L. G. 1912.—Sur le cycle evolutif du spiroptére du chien. Compt. Rend. Acad. Sc., vol. 154, No. 2, Jan. 8, pp. 82-84. 1912.—La grande blatte, héte intermédiaire de 1’échinorhynque moniliforme en Algérie. Compt. Rend. Soc. Biol., vol. 72, No. 2, Jan. 19, pp. 62-63. 1913.—Sur Vévolution du Physocephalus sexalatus (Molin). Compt. Rend. Soc. Biol., vol. 75, No. 35, Dec. 12, pp. 517-520, figs. 1-4. 1913.—Sur lévolution du Spirwra gastrophila Mill. Compt. Rend. Soc. Biol., vol. 74, No. 6, Feb. 14, pp. 286-289, figs. 1-3. 1916.—Contribution 4 l’étude des formes larvaires des nématodes parasites hetéroxénes. Bull. Scient. France et Belg., 7. s., vol. 49, No. 4, July 6, pp. 297-377, figs. 1-14. 1918.—Extension de Vhabitat du Spirura gastrophila (Mueller). Compt. Rend. Soc. Biol., vol. 81, No. 15, July 27, pp. 789-791. 96 SANITARY ENTOMOLOGY 1919.—Contributions nouvelles a l’étude des formes larvaires des nématodes parasites hétéroxénes.. Bull. Biol. France et Belg. (1918), vol. 52, No. 4, Mar. 25, pp. 344-878, figs. I-XII. Theiler, (Sir) Arnold, 1919.—A new nematode in fowls, having a termite as an intermediary host. [Filaria gallinarwm (nova species) ]. 5. & 6. Rep. Director Vet. Research, Dept. Agric. Union South Africa (1918), Apr., pp. 695-707, 1 pl., fig. 1. Van Saceghem, R. 1917.—Contribution a étude de la dermite granuleuse des equidés. Bull. Soc, Path, Exot., vol. 10, No. 8, Oct., pp. 726-729. 1918.—Cause étiologique et traitement de la dermite granuleuse. Bull. Soc. Path. Exot., vol. 11, No. 7, July 10, pp. 575-578. Villot, Francois Charles Alfred. 1878.—Migrations et métamorphoses des ténias des musaraignes. Ann. Sc. Nat., Zool., vol. 49, 6. s., vol. 8, Nos. 2-3, art. 5, 19 pp., pl. 11, figs. 1-14. 1883.—Mémoire sur les cystiques des ténias. Ann. Sc. Nat., Zool., 6. s., vol. 15, art. 4, Oct., 61 pp., pl. 12, figs. 1-13. Von Linstow, Otto Friedrich Bernhard. 1886.—Ueber den Zwischenwirth von Ascaris lumbricoides L. Zool. Anz., No. 231, vol. 9, Aug. 30, pp. 525-528. Von Stein, Friedrich. 1852.—Beitriige zur Entwickelungsgeschichte der Eingeweidewiirmer. Zeitschr. f.. Wissensch. Zool., vol. 4, No. 2, Sept. 2, pp. 196- 214, pl. 10, figs. 1-20, Wellman, Frederick Creighton, 1907.—Preliminary note on some bodies found in ticks Ornithodoros moubata (Murray) fed on blood containing embryos of Fi- laria perstans (Manson). Brit. Med. Journ., No. 2429, vol. 2, July 20, pp. 142-143. CHAPTER VI The Relations of Climate and Life and Their Bearings on the Study of Medical Entomology.* W. Dwight Pierce All animal and plant life has its being and reacts according to defi- nite laws in which we find the climatic factor of primary importance. We cannot go far into a subject with as many inter-relationships as medical entomology without finding it necessary to know something of the climatic laws which govern the lives of the various organisms con- cerned. In several of the lectures attention is especially called to apparent discrepancies in the interpretation of climatic effects on the life of the insects, and this is particularly true in case of the lice. Throughout our literature there is to be found a hazy notion of the importance of temperature and still hazier notions of humidity. There is a great’ deal about these factors which help to govern life, that no one knows, but it will pay us to have a clearly defined statement of some of the most important principles as now understood. On a proper understanding of the relations of temperature and humidity to the life and development of insects, animals, and disease organisms, depend all transmission experiments, all efforts in keeping alive the various creatures involved, all interpretations of results and many practical measures of control. This difficult subject will be stated in as simple language as possible so that all may see the basic principles at least. Every one of us knows that cold and heat can cause pain. We have indeed a clear understanding that cold and heat kill. We recognize the fact that we seem to work best under conditions when we are absolutely oblivious of heat or cold, dryness or moisture. We have felt stupid in murky weather. We have felt parched and dried from extremely dry weather. In other words, we can now recognize four conditions which may affect our well-being, cold, heat, dryness, moisture. These can be expressed on two scales—temperature and relative humidity. In other words, we should be able to chart our own susceptibilities to these factors by running, for example, a temperature scale vertically on our 1This lecture was read July 1, 1918 and issued the same day. 97 98 SANITARY ENTOMOLOGY chart paper and a humidity scale from zero to one hundred per cent- saturation horizontally. If we picture our reactions or those of the creature being studied on such a chart (see figs. 8, 9), we will better understand the subject. In the lower part of the chart we will locate certain temperatures which always cause death from cold. These may be known as ABSOLUTE FATAL TEMPERATURES. Now a common failing in the past has been to assume that humidity had nothing to do with the effect of temperature on life. It does have a very decided bearing. A creature which can stand a certain degree 3 * wa : MEAN TEMPERATURE THERMONOCHES ones suazongA z pPOKERAENOSIS -Dariy, ip ZONE OF GREATEST ACTIVITY, retin, NE OF a ‘ aw bs RHIGOPLEGIA- 2 & & Dicaees Faereanesy PERCENTAGE MEAN AUMIDITY. ww “” 2. * te AN HYPOTHETICAL CHART SHOWING THE ZONES OF LIFE REACTIONS TO TEMPERATURE AND RELATIVE HUMIDITY, DIFFERING FOR EACH SPECIES. Fic. 8 of cold at a given humidity may be absolutely unable to stand that same temperature at another degree of saturation or relative humidity. Our absolutely fatal temperatures therefore will form some sort of a zone on our chart and this zone will probably be bounded by a curve. We call the temperatures below this curve the LOWER ZONE OF FATAL TEMPERATURES. Death caused by cold is called RHIGO- PLEGIA. Slightly above these absolutely fatal temperatures will be a zone of temperatures which might cause death if experienced sufficiently long, but which at least cause a complete suspension of all activity. And still higher will be temperatures which also cause suspension of activity, but which do not cause death even when experienced for very long pe- RELATIONS OF CLIMATE AND LIFE 99 riods. Formerly, this suspension of activity by animal life on account of cold was called hibernation, which means winter rest. The writer has shown (Pierce, W. D., 1916, Journ. Agr. Res., vol. 5, pp. 1183-1191) that this same inactivity may be caused by dryness or heat and possibly by excessive humidity, and that a creature may remain in the same state of inactivity from the heat of summer through the cold of winter and be awakened from it only by the addition of a requisite amount of moisture at effective temperatures. We must seek other terms than hibernation, or winter rest, and aestivation, or summer rest. As this rest consists essentially of an almost complete cessation of all bodily functions, and is a state of insensibility, we may very properly designate the so-called hibernation as RHIGANESTHESIA, or insensibility due to cold. This state may be acquired naturally as winter sets in, or may be artificially induced at any time of the year by lowering the tempera- ture. The temperatures inducing RHIGANESTHESIA are grouped into the LOWER ZONE OF INACTIVITY, or the ZONE OF RHIG- ANESTHESIA. As the temperatures increase, a creature in the state of rest or rhiganesthesia, commences to show slow movements of the body fluids, and slight jerky motions, which increase with increase of temperature. This awakening or anastasis, when caused by temperature change, is a THERMANASTASIS. The approximate point at any given humidity at which thermanastasis begins is the ZERO OF EFFECTIVE TEMPERATURE. It must be . firmly fixed in your minds that there is not a single zero of effective temperature, as so often claimed, but a different one for every degree or portion of a degree of relative humidity. In other words, at one humidity the awakening may occur at one temperature, and under other conditions of humidity the temperature may be considerably higher or lower. These points can be connected by a curve which represents the lower limit of the ZONE OF ACTIVITY, or the THERMOPRACTIC ZONE, mean- ing a zone of effective temperatures. Many authors have manifested considerable confusion in their writ- ings and have even claimed that other authors were incorrect because a certain developmental period or reaction was accomplished in their ex- periments at a given temperature in a certain period of time while the other investigators obtained totally different results. A man working in a moist coastal section could not justly compare his results with those of a man working in a drier section unless the conditions of humidity were recorded also. For this reason, the writer has maintained that labora- tories attempting to correlate temperature with life history, must at least be equipped with maximum and minimum thermometers and a sling psychrometer for determining humidity, and that accurate results are 100 SANITARY ENTOMOLOGY based only on a recording hygrothermograph, checked by the above mentioned instruments. The great bulk of work naturally is upon the reactions which take place in the zone of activity. It must not be forgotten, however, that control work depends often upon a correct knowledge of the lower zone of fatal temperatures, and that successful storage of breeding material, until the investigator is ready to use it, depends often upon a knowledge of the requirements of rhiganesthesia. Following the awakening, the body takes up all its natural functions and we must assume that sustenance is available. The first activities, at temperatures just above the zero of activity, are naturally very sluggish and this state of sluggishness may be known as RHIGO- NOCHELIA, or sluggishness caused by cold. Some creatures are very sensitive to cold, usually when the humidity is high. Pain produced by the application of cold is called CRYAL- GESIA. An abnormal sensitiveness to cold is known as CRYESTHESIA, and a morbid sensitiveness as HYPERCRYALGESIA. These sensa- tions are probably only experienced with a descent of temperatures. In the zone of effective temperatures or thermopractic zone there is a point or a small restricted zone of temperatures at which all activi- ties are most effective, that is, the greatest amount of work is accom- plished with the least amount of exertion and the least loss of energy. This is the so-called OPTIMUM, or perhaps better, PRACTICOTATUM, meaning most effective. As temperatures ascend to the practicotatum any given function is performed in proportionately shorter time. As the temperatures ascend above the practicotatum a particular function may be exercised more rapidly but less accurately or less effectively, as for instance, more eggs may be laid but fewer hatch: but the activity is feverish and soon exhaustion takes place, or the individual gradually becomes more stupid and sluggish. This heat sluggishness is therefore called THERMONOCHELIA. Different reactions to heat may be experienced and these have all received appropriate designations. As for example, a stifling sensation is called THERMOPNIGIA; an unusual sensibility to heat THERMAL- GESIA, and a more intense sensibility HYPERTHERMALGESIA. The ability to recognize changes of temperature is THERMESTHESIA, and its extreme is designated as THERMOHYPERESTHESIA, an abnormal sensitiveness to heat stimuli. A fondness for heat or requiring. great heat for growth is called THERMOPHILIC, while resistance to heat is called THERMOPHYLIC. Wher a stifling temperature is ex- perienced rapid breathing or THERMOPOLYPNEA is often experi- enced. Contraction under the action of heat is designated as 'THER- y RELATIONS OF CLIMATE AND LIFE 101 MOSYSTALTIC. The adaptation of the body temperature to that of the environment is PECILOTHERMAL. A morbid dread of heat is THERMOPHOBIA. The determination of the direction or rate of locomotion by heat is called THERMOTAXIS and movement brought about by heat is THERMOTROPISM. As the temperatures increase sluggishness increases until sleep or inactivity is induced and this condition once known as aestivation or summer rest may better be known as THERMANESTHESIA or insensi- bility caused by heat. The point at which anesthesia begins at any given humidity is the upper boundary of the thermopractic or effective zone. Those tempera- tures at which successful Thermanesthesia may be experienced embrace the UPPER ZONE OF INACTIVITY, or the ZONE OF THERM- ANESTHESIA. This quickly merges into those high temperatures which may with sufficient duration of time cause death, and finally, those tem- peratures which are absolutely fatal under all conditions. ‘The highest zone is therefore the UPPER ZONE OF FATAL TEMPERATURES. Death from heat is known as THERMOPLEGIA, or heat stroke. Most investigators have stopped with a more or less hazy acknowledg- ment of the existence of these various zones of reactions on the ascend- ing scale of the thermometer, but the literature contains few references to similar zones of reactions on the scale of relative humidity. However, if we stop to think we must acknowledge that similar reactions do take place. We may have death from absolute dryness at almost any tempera- ture, in other words, we have a condition which is called APOXERAE- NOSIS, or drying up. At very low humidities one may become insensi- ble and thus we have XERANESTHESIA. Likewise, a little higher humidity induces sluggishness or a state of KERONOCHELIA. We have most of us experienced this condition of stupidity in a living room at normal temperatures in the winter due to lack of sufficient moisture. So also there is the humidity which enables each individual to accom- plish the greatest results in the least time with the least amount of exhaustion and this is the PRACTICOTATUM. With increase of humidity the activity lessens until an excessively humid atmosphere brings about HYGRONOCHELIA or sluggishness due to moisture; then HYGRANESTHESIA may be experienced by some species and finally death due to excessive moisture or HYGROPLEGIA. This makes it obvious therefore that when we plot the reactions of a species to temperature and humidity, we are likely to find a series of closed figures delineating concentric zones of fatal, inactive, active and optimum conditions. Thus it is apparent that Rhigoplegia, Apoxeraeriosis, Thermoplegia, and Hygroplegia form a single zone of 102 SANITARY ENTOMOLOGY temperature-humidities which cause death—this whole zone is the fatal or OLETHRIC ZONE. All conditions of life lie within it, the next zone being that which includes Rhiganesthesia, Xeranesthesia, Thermanes- thesia, and Hygranesthesia; the whole zone therefore being the ANES- THETIC ZONE, or zone of rest, which includes the conditions known as hibernation and aestivation. Within this is the THERMOPRACTIC ZONE or zone of effective temperatures, which is naturally made up of sub-zones representing degrees of activity, as the NOCHELIC SUB- ZONE of sluggish activities on the outside and the PRACTICOTATUM at the center. PERCENTAGE «MEAN MUMIDITY. 2 ® a » 2 od SUCCESTED CURVES OF THE RESPONSES OF AVERAGE AMERICANS TQ HUMID A TEMPERATURES WITH CERTAIN ACTUAL RECORDS SERVING AS A BASIS. Fig. 9 Temperature and humidity affect every bodily function of every creature of the plant and animal kingdom. Some creatures may love cold, some heat, some dryness, some moisture. The pattern of their reactions will therefore shift from one place to another on the chart. Some creatures may be so resistant to cold that fatal temperatures are never normally experienced and rarely artificially. Some may be very resistant to dryness and others capable of standing any degree of hu- midity. In case of plants the root system receives one set of stimuli and the upper portion another, so that the interpretation is not as simple as with animals. In the different stages of growth a creature may have different abil- ity to withstand extremes. If the approach to unfavorable or noneffective conditions is gradual, RELATIONS OF CLIMATE AND LIFE 103 the body gradually adjusts and adapts itself for entrance into a dormant state. We find adaptations against cold, heat and dryness, often in cysts or in cases constructed by the creature, and in fact some of these protective cases are made of substances impervious to water. In the state of encystment far greater extremes can be experienced than in the normal state, because of the impervious nature of the cyst. Successful dormancy often depends upon the rapidity with which it was brought about. Most creatures practically free the intestinal canal before entering a resting stage. A sudden lowering or raising of temperature may be fatal at tem- peratures which would normally be easily withstood if approached grad- ually. Alternation of high and low temperatures, if sudden, is often fatal at normally effective temperatures. A creature may become dormant with descending temperatures at a higher temperature than it would awaken with ascending temperatures. A continuous maintenance of an even temperature and humidity is more or less enervating. A climate which has sufficient variation to allow certain periods of rest from cold at night and heat in the day is probably productive of better results. It is possible in a given day for a creature to have two active and two dormant periods. As for example, observations of many insects will show that they sleep during the cold parts of a night, are active during the morning, sleep during the hottest part of the day, are again active in the evening and early parts of the night. It is also noticeable that on humid days many in- sects are inactive but as soon as the air dries they again resume activ- ity, and the reverse is found in arid regions. Many investigators have failed in keeping insects alive for experi- ment because of failure to keep sufficient water present for drinking purposes and maintenance of proper humidity. As long as any creature is experiencing effective temperatures it must have food available to take when needed and this food must be in proper condition. Long periods without food at noneffective tempera- tures can be experienced, but at effective temperatures the length of life is relatively short. This is a very important point in control work with all insects. If you can deprive them of food for a sufficient period when the climatic conditions enforce activity, then control is easy. There are many very difficult points in this question. Inasmuch as noneffective temperatures and also noneffective humidities may be experienced each day, it becomes necessary to make elaborate studies to ascertain the boundaries of the thermopractic and hygropractic zones, and only a thermo-hygrograph record sheet will enable one to make any kind of a satisfactory study. 104 SANITARY ENTOMOLOGY There is a rule which receives much support, that a given reaction or stage of development is accomplished at an almost constant total effective temperature, which is the multiple of time units by temperature units accumulated above the zero of effective temperature. Since the zero varies with the humidity, the total effective temperature obtained by this rule does likewise. We must therefore reword the rule to read: A given reaction or stage of development is accomplished at any given mean humidity at a constant total effective temperature, which is the multiple of effective time units by temperature units accumulated within the zone of effective temperatures at a given atmospheric pressure. To compute this one must first eliminate all time, temperature, and humidity which was noneffective, whether at the top or bottom of the scale. For instance, if at 60% humidity the temperatures 65° to 85° are effective, and during the day the temperature ranged from ‘50° to 90°, but only during eight hours at the effective temperatures; we must multiply the period 8 hours by the mean temperature experienced be- tween 65° and 85°, considering 65 as 0 and 85 as 20. The result is the total effective temperature of that day. Adding these total effective temperatures during the total period of the stage, we obtain the total effective temperature necessary to bring about the perfection of the stage. Necessarily this is a very complicated proposition, requiring very careful computations. Nevertheless, once worked out we can es- tablish laws of control which are of utmost value. Some of the following lectures will refer to the principles laid down in this lecture and lines of research will be suggested leading toward control measures. The charts (figs. 8, 9) should be studied in connec- tion with the lecture. CHAPTER VII Diseases Borne by Non-Biting Flies ? W. Dwight Pierce It will be necessary in discussing the réle of flies in the transmission: of disease to divide the flies into several categories, because so many species of the order Diptera are involved. The flies can be divided into two large groups, those which bite and those which do not bite, but, rather, sip their food. Two excellent monographs on the relations of flies and disease have been published, that on the non-bloodsuckers by Graham-Smith, and that on the bloodsuckers by Hindle. This lecture deals with the non-biting flies only. Among these flies are to be found the principal house-visiting flies, foremost among which is the house or typhoid fly, Musca domestica Linnaeus, followed by the. blue bottle blow flies, Calliphora vomitoria Linnaeus and C. erythro- cephala Meigen, the green bottle blow fly Lucilia caesar Linnaeus, and. various other species. The mouth parts of these flies are constructed only for sucking or sipping liquid or semi-liquid foods. In this lecture can only be given a very condensed statement of the relationship of these flies to disease. A more extensive study should. involve the reading of the books by Hewitt and Graham-Smith quoted. in the bibliography. In these volumes the evidence is given in great detail. Among the most striking of the investigations into the capacity of non-biting flies for the carriage of disease germs, are a series of three. excellent papers by the Italian investigator, Cao, whose work is over- looked by many subsequent writers. In fact, there has been but one. good review of his results in English.. And yet his investigations opened. up the way for practically all of the work on bacterial transmission by insects. Working with larvae and adults of Musca domestica Linnaeus, Calliphora vomitoria Linnaeus, Lucilia caesar Linnaeus and Sarcophaga. carnaria Linnaeus, he proved that the larvae of these flies could take up and pass through their intestines any bacteria occurring in their: food, and that all four species acted exactly alike in this regard. Except where he specifically stated, his results applied to all four species in 1This lecture was presented in two parts on July 8 and 15 and distributed entire. on July 15, 1918. It has been revised for this edition. 105 106 SANITARY ENTOMOLOGY every instance. Step by step, he proved that fly-larve take up bacteria from their food, and when breeding in flesh may take up disease germs as well as non-pathogenic germs; that these germs may pass unaltered through the insects’ intestines and out in their feces; that some of them may remain for a long period in the intestinal canal, and some even may multiply therein; that they may be taken up by the larva and per- sist through its metamorphosis until it arrives at the adult stage, and for days thereafter, and may be carried by this adult and deposited with its feces on food or excrement; and that these bacteria will also be fownd in the glutinous substances surrounding the eggs when deposited, and thus contaminate the substance in which the newly born larvae will feed; and of course be taken up by this second generation and possibly a be distributed farther by it. These facts were worked out by Cao in 1905 and 1906, and yet Graham-Smith credits Faichnie (who worked in India in 1909) with be- ing the first one to suggest that bacteria ingested by the larva might survive the pupal stage and be present in the intestine of the adult. Later, Bacot, and also Ledingham in 1911 and Graham-Smith in 1912, corroborated these claims that the bacteria could persist in the body throughout the metamorphosis. Ledingham (1911), Nicholls (1912), and Graham-Smith (1912) have shown that the fly larve have great powers of destroying micro- organisms due to the fact that many of these organisms are not adapted to the conditions prevailing in the interior of the larva and pupa, or perhaps more correctly due to the hostile action of bacteria which more normally frequent the intestines of the larve. These normal inhabitants of the fly intestine are principally non-lactose fermenting organisms. Not only bacteria but also protozoa, such as the amoebae of dysen- tery, and the eggs of parasitic worms, may be taken up by the fly larve or adults and deposited in the feces. Roubaud (1918) has brought out the fact that multitudes of the amoebic dysentery germs taken up by adult flies and deposited in their feces die because of the rapid drying of the feces, and he credits the fly with being a great agent in the de- struction of multitudes of protozoa, while granting the equally great opportunity of the fly to contaminate food therewith. Stiles in 1889 fed larve of Musca domestica with female Ascaris lumbricoides, which they devoured, together with the eggs they con- tained. The larvae as well as the adult flies contained the eggs of Ascaris (Nuttall, 1899, p. 39). Nicoll (1911) has very thoroughly in- vestigated the relationships of flies to the possible carriage of eggs of worms and demonstrated the ability of adult flies to ingest the eggs of various species of worms, provided these are small enough, and to pass DISEASES BORNE BY NON-BITING FLIES 107 them out whole in the feces, but in all his experiments with the larvae he found that the eggs were crushed. In addition to the ability of flies to carry disease germs in their body, there are multitudes of proofs of their ability to carry them also on their body and to deposit them when they feed. The transmission of disease by non-bloodsucking flies is exclusively by contamination either of food, water or wounds. Most of the flies which frequent houses and food or visit man because of attractive secre- tions or injuries also are attracted to and breed in excreta or garbage. Hence the contamination of food by direct transportation from infected excreta is a very simple matter. This contamination may be by the simple depositing of disease germs carried on the body of the flies, or by regurgitation, or the deposition of feces. Wherever a fly alights and remains a few minutes it deposits either vomit or feces. By the nature of its breeding it is hardly to be expected that these deposits will not contain some kind of bacteria, and possibly protozoa or worm eggs. If these deposits are made on the moist media. offered by foods the germs may easily retain their virulence until eaten. As flies can travel considerable distances, at least thirteen miles, the existence of a single disease case with insanitary conditions in the vicinity enabling fly breeding, might easily infect an entire city or army camp if the flies were permitted to reach the food of the inhabitants. It is because of the total lack of sanitary waste disposal in country dis- tricts that diseases like typhoid fever and dysentery usually become very widespread. We can not know the source of the flies which enter our houses. We must not let them visit our food. They must be kept away from the eyes and mouths of babies. Our markets where meats and vegetables are sold must be better protected. Only through influencing public opinion will we be able to have the fly nuisance in our own public markets abated. Food offered for sale should be kept under glass or screen at all times. There are so many organisms transmitted by the non-blood-sucking flies that we shall have to deal with them rather briefly and preferably according to their classification. A thorough digest of the mass of matter submitted below should impress the readers with the necessity of fly prevention. PLANT ORGANISMS CARRIED BY NON-BITING FLIES Thallophyta: Fungi: Schizomycetes: Coccaceae Streptococcus equinus Andrewes and Horder, a non-pathogenic organ- ism found in horse dung, was found by ‘Torrey (1912) in a number of cases on the surface of city caught flies. 108 SANITARY ENTOMOLOGY Streptococcus fecalis Andrewes and Horder, an organism occurring normally in the human intestine and occasionally pathogenic has been isolated from city caught Musca domestica by Scott (1917), Cox, Lewis and Glynn (1912) and Torrey (1912). Streptococcus pyogenes Rosenbach, an organism causing ERYSIPE- LAS, SUPPURATION and SEPTICAEMIA was isolated by Scott (1917) from city caught Musca domestica in Washington. Streptococcus salivarius Andrewes and Horder, an organism fre- quently found in the mouth, but rarely pathogenic, has been isolated from the intestines of city caught Musca domestica by Torrey (1912), and was also found on flies by Cox, Lewis and Glynn (1912). Diplococcus gonorrhoeae Neisser (Gonococcus), the cause of GONOR- RHOEA, was found by Welander (1896) carried on the feet of a fly for three hours after they had been soiled with secretion. Diplococcus intracellularis meningitidis Weichselbaum (Meningococ- cus), the cause of CEREBROSPINAL MENINGITIS, is thought to be possibly carried by flies by MacGregor (1917). Micrococcus flavus was isolated by Torrey (1912) from the intes- tinal content as well as the surface of city caught flies. Micrococcus tetragenus Gaffky, commonly found in the human body, sometimes pathogenic, sometimes saprophytic, was isolated from Musca domestica by Scott (1917). Staphylococcus pyogenes albus Rosenbach, a cause of SEPTICAE- MIA, was isolated by Cao (1906B) from the mucilaginous envelope cov- ering the eggs of Musca domestica, Sarcophaga vomitoria, Lucilia caesar and Calliphora vomitoria at the time of deposition. Scott (1917) iso- lated it from the bodies of Musca domestica. Staphylococcus pyogenes awreus Rosenbach, a frequent cause of ABSCESSES, etc., was shown by Celli (1888) to retain its virulence after passing through the flies’ intestines. Herms (1915) proved by experi- ment that Musca domestica can carry great numbers of this organism on its feet. Torrey (1912) and Scott (1917) isolated it from the bodies of city caught flies. Cao (1906B) isolated it from the eggs at the time of deposition of laboratory caught flies of Musca domestica, Calliphora vomitoria, Sarcophaga carnaria and Lucilia caesar. Staphylococcus pyogenes citreus Passet, a pathogenic, chromogenic, pus-forming organism, was isolated by Scott (1917) from bodies of house flies Musca domestica in Washington. Cao (1906B) fed larvae of Musca domestica, Sarcophaga carnaria, Calliphora vomitoria, and Lucilia caesar on meat polluted with this organism and recovered it from the feces of mature flies bred from these larvae. Sarcina aurantiaca Lindner and Koch, a zymogenic, chromogenic (orange yellow) organism found in air and water, rarely pathogenic, DISEASES BORNE BY NON-BITING FLIES 109 was found by Cao (1906B) to be capable of passing through the intes- tines of larve of Musca domestica, Calliphora vomitoria, Sarcophaga car- naria, and Lucilia caesar, in all stages of larval growth and of remaining in the body through pupation to maturity. Thallophyta: Fungi: Schizomycetes: Bacteriacee Bacillus of Koch-Weeks, the cause of an acute infectious CONJUNC- TIVITIS (pink eye), is thought by Castellani and Chalmers (1913, p. 700) to be frequently carried by the little Oscinid gnat, Microneurwm funicola Meijere, which causes great annoyance by hovering in front of the eyes and attacking the eyes and ears. The flies may be driven away by the odor of Odol. Bacillus A of Ledingham, a nonlactose fermenter from the feces of children, has been found by Tebbutt (1912) to be normal to the house fly, Musca domestica, being found on the ova, and in the larve, pupe and adults, and when fed to the larve survived through the metamorphosis to the adult stage. Bacillus of Morgan, which is frequently found in cases of INFAN- TILE DIARRHEA, has been found in various strains commonly in the intestines of Musca domestica by Nicoll (1911), Morgan and Ledingham (1909), Cox, Lewis and Glynn (1912) and Graham-Smith (1912), and the latter found that when fed to larve of the house fly it could survive through the metamorphosis to the adult fly. Bacillus acidi lactici Hueppe, a bacillus common to cows’ milk, has been isolated from the bodies and from the intestinal contents of Musca domestica in New York, Washington, London and Liverpool by Torrey (1912), Scott (1917), Nicoll (1911), and Cox, Lewis and Glynn (1912). Bacillus aerogenes capsulatus Welch and Nuttall is a pathogenic organism gaining entrance to the body chiefly through wounds and caus- ing severe infections resulting often in GANGRENE. In the surgery of the Great War this organism has been a very important one. It occurs as a normal inhabitant of the intestine of man and some of the animals. It has been isolated by Torrey (1912) from the surface as well as the intestinal contents of city caught flies. Bacterium anthracis Davaine, the cause of ANTHRAX, although probably more often carried by biting flies, has been shown by Davaine (1870) to be capable of carriage by Calliphora vomitoria. He fed flies on anthracic blood and inoculated guinea pigs with parts of these flies 40 hours to 3 days later, obtaining fatal results in 4 out of 7 cases. From flies of Calliphora vomitoria caught in his laboratory Cao (1906B) ‘isolated virulent germs of B. anthracis adhering to the glutinous secretion surrounding the eggs as they were deposited. He later placed on flesh 110 SANITARY ENTOMOLOGY of animals dead from anthrax externally sterilized eggs of Musca domestica, Calliphora vomitoria, Lucilia cesar and Sarcophaga carnaria and from day to day dissected the larve feeding on this flesh, always demonstrating anthrax germs in their bodies, and he further proved that these larve retained the germs in their bodies through pupation to maturity and for at least nine days after maturity. He fed flies on meat polluted with anthrax and demonstrated twenty-four hours later the bacilli in the feces and on the eggs. Graham-Smith (1912) found that many blow flies (Calliphora erythrocephala and Lucilia cesar) which emerged from larve fed on meat infected with anthrax spores were infected and remained so for 15 days or more. He also found that a large proportion of house flies (Musca domestica) which develop from larve fed on spores of B. anthracis are infected. Because of the habit of blow flies of breeding in and attacking wounds there have been many cases of human anthrax on the battle front in Europe. The ease with which this may occur is quite evident in view of the above quoted investigations. Bacillus cloace Jordan has been found in the alimentary canal of Musca domestica in London by Nicoll (1911). Bacillus coli Escherich, an organism normally found in the alimentary canal of man, but often found causing secondary infections, was found by Cao (1906B) in various strains adhering to the eggs at the time of oviposition of flies caught in the laboratory (Musca domestica, Sarco- phaga carnaria, Lucilia cesar, and Calliphora vomitoria). Bacillus coli anaérogenes was isolated by Scott (1917) from Musca domestica caught in Washington. Bacillus coli communior Dunham, an abundant inhabitant of the human and animal intestine, has been isolated from the body and intes- tinal contents of Musca domestica in New York and Washington by Torrey (1912) and Scott (1917). Bacillus coli communis Escherich, an organism common in the intes- tine of man and animals and associated with a large variety of lesions, has been isolated from the body and intestinal contents of Musca domestica by Torrey (1912), Nicoll (1911), Scott (1917) and Cox, Lewis and Glynn (1912). Bacillus coli mutabilis was found on the body and in the intestines of Musca domestica in London by Nicoll (1911). Bacillus “colisimile’ Cao was fed by. Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar and Sarcophaga carnaria in flesh and he later demonstrated its abundant presence in the feces of the larve. Bacillus cuniculicida Koch and Gaffky, the cause of SEPTICEMIA in rabbits and guinea pigs, was isolated by Scott (1917) from house flies (Musca domestica) caught in Washington, and he looks upon the fly DISEASES BORNE BY NON-BITING FLIES 111 as the carrier of laboratory epidemics of rabbit and guinea pig septicemia experienced for several years. Bacillus diphtherie Klebs, the cause of DIPHTHERIA, according to experiments performed by Graham-Smith (1910) may be taken up by flies feeding on infected saliva or sputum and may live in the crop and intes- tines of the fly for over 24 hours, and in fact in one experiment he twice _recovered it from the feces of flies 51 hours after feeding on bacilli emulsi- fied in broth. Bacillus dysenterie “Y” Hiss and Russell, one of the organisms found in DYSENTERY and INFANTILE DYSENTERIC DIARRHEA, was experimented with by Tebbutt (1913) who fed it with blood to larve of Musca domestica. The eggs from which these larvae were hatched were washed in weak carbolic acid or lysol to disinfect them. Before feeding the larve on the organism they were carefully washed in weak lysol solution. In a limited number of cases the bacillus was recovered from the pup and adults of larve thus fed. The Shiga bacillus, Flexner bacillus and parabacillus of dysentery were all isolated on flies in Macedonia and a decided correlation between the incidence of flies and dysentery was established by Col. Dudgeon (1919) and associates. They found the examination of fly feces the most suitable method for the isolation of dysentery bacilli. Bacillus enteritidis Gaertner, the cause of FOOD POISONING in man, and epizootic diseases among animals, was experimented with by Graham-Smith (1912), who fed it tothe larve of Calliphora erythro- cephala and Musca domestica, but did not recover it in the adults matured from these larve. Cox, Lewis and Glynn (1912) isolated a similar bacillus from flies caught in Liverpool. Bacillus fecalis alkaligenes Petruschky, a not infrequent inhabitant of the human intestine, which has been associated with a case of severe gastroenteritis, was isolated by Torrey (1912) from the intestinal con- tent of city caught flies in two different instances. Bacillus fluorescens liquefaciens Fluegge, a common organism found in water and air, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar, and Sarcophaga carnaria, on flesh containing the organisms, and found among the predominant bacteria in the feces of the larve. He found that this organism taken up by the larve could persist through the pupal stage and be obtained from the feces of flies immediately after their emergence, and when fed to adults it was demonstrated on their eggs when deposited. Bacillus fluorescens nonliquefaciens Eisenberg and Krueger, found in water and in butter, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar, and Sarcophaga carnaria, and later demonstrated in the feces of the larve. 112 SANITARY ENTOMOLOGY Bacillus gasoformans nonliquefaciens was found on the body and in the alimentary canal of Musca domestica caught in London by Nicoll (1911). Bacillus griinthal was found on the body and in the intestines of Musca domestica by Nicoll (1911). Bacillus lactis acidi Marpmann, a zymogenic bacillus found in cows’ milk, was isolated by Torrey (1912) from the surface of city caught flies, Bacillus lactis aérogenes Escherich, which is almost constantly found in milk and is one of the chief causes of souring of milk, was isolated from flies by Cox, Lewis and Glynn (1912). Bacillus lepre Hanson, cause of LEPROSY, may be carried by Musca domestica, according to Leboeuf (1913). Bacillus mallet Loffler and Shutz may be transmitted by flies according to Rosenau (1916). Bacillus neapolitanus has been found on.the body of Musca domestica by Nicoll (1911) and Cox, Lewis and Glynn (1912). Bacillus oxytocus perniciosus Wyssokowitsch, a pathogenic organism found in milk, has been isolated from the intestines of Musca domestica by Nicoll (1911). Bacillus paracoli Duval and Schorer, a pathogenic organism found frequently in the stools of children suffering from summer diarrhea, has been isolated several times by Torrey (1912) in New York, both from the surface and intestines of city caught flies. Bacillus paratyphosus “A”? Schottmiiller, cause of PARATYPHOID A fever was isolated from the intestinal contents of city caught flies by Torrey (1912). Bacillus paratyphosus “B” Schottmiiller, cause of PARATYPHOID B fever, was recovered from the body and intestines of Musca domestica caught in London by Nicoll (1911), with the evidence that it had been carried by the flies at least for 11 days. Bacillus pestis Kitasato, the cause of BUBONIC PLAGUE, although normally carried by fleas, has been shown by Yersin (1894) and Nuttall (1897) capable of remaining in the intestines of flies in a virulent condi- tion for at least 48 hours after infection. Nuttall’s experiments indicated that this bacillus is fatal to Musca domestica. ; Bacillus prodigiosus Ehrenberg, a nonpathogenic, zymogenic, and chromogenic organism, was fed by Cao (1906B) to adult flies of Musca domestica, Calliphora vomitoria, Lucilia cesar, and Sarcophaga carnaria and was demonstrated in their feces and on their eggs 24 hours later. Larve fed on polluted meat contained the germs in their bodies and carried them through pupation and they could be demonstrated in the intestines of the adult up to nine days after emergence. Ledingham (1911) corroborated Cao’s findings of the persistance of this bacillus DISEASES BORNE BY NON-BITING FLIES 113 throughout the metamorphosis of Musca domestica. Graham-Smith (1913) found that flies of Musca domestica fed on this bacillus may infect milk for several days, while Calliphora vomitoria flies when infected con- stantly produced infection in milk up to the eighth day and in syrup up to the twenty-ninth day. Bacillus proteus vulgaris Hauser, B. p. mirabilis Hauser, and B. p. zenkeri were fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Sarcophaga carnaria, and Lucilia cesar, and were found abundantly in the feces of the larve so fed. Species of Proteus were also found deposited with the eggs of flies fed on infected flesh. Bacillus proteus vulgaris was isolated by Scott (1917) from Musca domestica caught in Washington. Bacillus pyocyaneus Gessard associated with SUPPURATING WOUNDS in which blue-green pus is present was isolated in two strains from flies caught in Liverpool by Cox, Lewis and Glynn (1912). Bacot and Ledingham (1911) by carefully controlled experiments have proved that the larve of Musca domestica fed on infected food retain this bacillus in the gut through the metamorphosis to the adult stage and may dis- tribute it in their excreta. Bacillus radiciformis Tataroff, a saprophytic organism found in water, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar and Sarcophaga carnaria, and recovered from the feces of the larve. Bacillus ruber kielensis Breunig, a chromoparous (red) bacillus found -in water at Kiel, was fed by Cao (1906B) to larve of Musca domestica, Sarcophaga carnaria, Calliphora vomitoria, and Lucilia cesar, and he demonstrated that the larve could take it up in all stages of growth, and that the bacilli persisted in their bodies through pupation to maturity. Bacillus schaffert Freudenreich, a nonpathogenic, zymogenic organism, found in “puffy” and “Nissler’” cheese, has been found by Nicoll (1911) in London on the body and in the intestines of Musca domestica. Bacillus septicus agrigenus Nicolaier, a pathogenic organism, was fed by Marpmann (1897) to flies, and 12 hours later the contents of the flies were inoculated into mice, producing fatal infection in a large per cent of the inoculations (Nuttall 1899). Bacillus “similcarbonchio” Cao, a pathogenic organism similar to Bacillus anthracis, which produces CARBUNCLES when inoculated, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar and Sarcophaga carnaria and isolated from the feces of the larve in a very virulent strain. In examinations of many flies caught in the laboratory he occasionally isolated a non-pathogenic, mobile strain of this organism. Bacillus subtilis Ehrenberg, an organism frequently found in air, 114 SANITARY ENTOMOLOGY water, and soil, and seldom pathogenic, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar and Sarcophaga carnaria and was among the predominant bacteria recovered from the feces of the larve. Bacillus suipestifer Salmon and Smith, often found in cases of FOOD POISONING and SUMMER DIARRHEA, is recorded by Scott (1917) from the house fly, Musca domestica. Bacillus ‘‘tifosimile” Cao, a pathogenic organism strongly resembling B. typhosus, was fed by Cao (1906B) to larve of Musca domestica, Calliphora vomitoria, Lucilia cesar, and Sarcophaga carnaria and later demonstrated in the feces of the larve as among the predominant forms in strains of differing virulence.. From flies caught around the laboratory he isolated pathogenic strains adhering to the eggs when deposited. Bacillus tuberculosis Koch, the cause of TUBERCULOSIS, was found in four out of six flies caught by Hofmann (1888) in the room of a tuber- culosis patient, whose sputum had contained many germs. Flies fed artificially with sputum died in a few days. Within twenty-four hours of their being fed on the sputum, the tubercle bacilli appeared in their excreta. A guinea pig inoculated with the intestines of flies developed tuberculosis. Celli (1888) reports Alessi’s experiments of inoculating the feces of flies fed on tubercular sputum, and causing the development of tuberculosis in two rabbits. Spillman and Haushalter (1887) were, however, the first to find the tubercle bacilli in the intestines and feces of flies which had fed on sputum. Bacterium tularense McCoy and Chapin, cause of a fatal RODENT PLAGUE of which a few human cases are on record, may be transmitted by Musca domestica, Wayson (1915) inoculated the crushed bodies of flies fed on the viscera of an animal dead 48 hours and obtained fatal results in three series of experiments with guinea pigs. Bacillus typhosus Eberth, the cause of TYPHOID FEVER, was first shown by Celli (1888) to be capable of passing through the intestines and into the feces of flies. Many authors have added proofs of the réle of the fly in the transmission of this disease and these are ably summarized by Graham-Smith (1913) and Hewitt (1914). Faichnie (1909) proved that flies could carry this bacillus in their intestines for 16 days. Leding- ham has isolated the bacillus from the intestines of Musca domestica which had fed on it in the larval stage, but found that the normal bacilli in the larval intestines usually prevent its successful survival through meta- morphosis. Bacillus vesiculosus, which is very frequently found in human excre- ment, was found on the body of Musca domestica caught in London by Nicoll (1911). Bacillus xerosis Kutschert and Neisser, a presumably nonpathogenic DISEASES BORNE BY NON-BITING FLIES 115- organism, usually found in the eyes, and often associated with conjunc- tivitis, was isolated by Torrey (1912) on the surface of city caught flies. Thallophyta: Fungi: Schizomycetes: Spirillaceae Spirillum (Vibrio) cholere Koch, the cause of ASIATIC CHOLERA, may be carried by flies. The connection of flies with the prevalence of cholera was first noted by Nicholas (1873). Maddox (1885) first per- formed experiments with Calliphora vomitoria Linnaeus and Eristalis tenaz Linnaeus as well as other insects and determined microscopically the presence of the motile cholera vibrios in the feces. Tizzoni and Cattoni (1886) caught flies in cholera wards and after several hours obtained characteristic cultures of the organism. Many other authors, as Sawtchenko (1892), .Simmonds (1892), Uffelmann (1892), Macrae (1894), have furnished proofs of fly dissemination of the cholera vibrio, a summary of which can be found in the books by Graham-Smith and Hewitt. SUMMARY OF PLANT ORGANISMS A brief survey of the data presented above will perhaps help to imprint the gravity of the fly menace on all who read this. Sixty-three minute plant organisms have been shown to be transmissible by domestic flies. Forty-four of these organisms have been found on or in flies caught in cities or buildings, in other words, were naturally carried by so-called “wild flies.” Among these forty-four organisms naturally carried by flies were several normal inhabitants of milk, also various normal inhabitants of the human and of animal intestines, which could only be taken up from excrement. Some of these organisms are taken from eyes, some from sputum, some from decaying vegetable matter, others from dairy products. The fly containing such organisms betrays its habits. We find the organisms of conjunctivitis, infantile diarrhea, sour milk, gas gangrene, enteritis, guinea pig septicaemia, leprosy, paratyphoid A, and paraty- phoid B fevers, bubonic plague, green pus, food poisoning, tuberculosis, typhoid fever, anthrax, rodent plague, gonorrhea, abscesses, erysipelas, bacillary dysentery, and cholera, and possibly cerebrospinal meningitis, normally carried by flies which frequent our houses, visit our bodies and pollute our food with their excreta. We also find experimental evidence that these same flies can carry the organisms of diphtheria, gastroenter- itis, and other pathogenic conditions. In other words, it would seem that non-blood-sucking flies can carry any bacterial or coccal disease in which the organism may be reached by the fly on the body of the person, in his sputum, or his excreta, and undoubtedly the same is true of such diseases of animals. 116 SANITARY ENTOMOLOGY It is of interest to note that in nineteen species the organism has been proven to pass freely through the intestinal canal of the larvae, in thirty- seven species through the intestines of the adult, and in eleven species to be capable of persisting in the larve through metamorphosis to the adult. What greater argument could be found that flies are dangerous not only because of what they as flies have fed on, but also because of food they took while larve, possibly a long distance away? We have not, however, gauged the depth of the fly’s infamy, as we have so far only listed the evidence of plant diseases transmitted. DISEASES OF UNSETTLED ORIGIN PROBABLY CAUSED BY MICROORGANISMS PURULENT OPHTHALMIA is said to be carried by flies in Egypt. Brumpt accused Musca domestica of being a carrier of TRACHOMA. Rosenau stated that flies have been found breeding in open lesions of SMALLPOX, and that flies may transmit MEASLES and SCARLET FEVER. Definite experiments certainly should be carried out with a view to determining the exact relationship of flies to these diseases, seek- ing first the possibility of transmission by fecal contamination. Howard and Clark (1912) found that Musca domestica flies can retain the virus of INFANTILE PARALYSIS or POLIOMYELITIS either in or on their bodies for 24 and 48 hours. The virus may remain alive in the body of the fly six hours after ingestion. The fly can obtain the virus from secretions of nose and throat and discharge of intestines. Very recently Dorset (1919) and associates have experimentally transmitted HOG CHOLERA by inoculating with crushed bodies of infected Musca domestica and Fannia canicularis, and also by bringing such flies in contact with abraded surfaces. ANIMAL ORGANISMS CARRIED BY NON-BITING FLIES We will now consider in a similar manner the evidence of transmission of animal organisms by these same flies. Protozoa Sarcodina: Amoebina: Amoebidae Léschia coli (Lésch) (Endamoeba) a supposedly harmless commensal in the alimentary canal of man, where it feeds on the contents of the. bowels, may be carried in the encysted form by Musca domestica, accord- DISEASES BORNE BY NON-BITING FLIES 117 ing to Roubaud (1918), who finds that the cysts readily pass through the fly intestines at laboratory temperatures of 15-18° C. (59-65° F.) in 24 hours. It may be carried from iufected stools to food but must be deposited in moist substances, as all cysts dry rapidly in dry fly feces. Léschia histolytica (Schaudinn), the cause of AMOEBIC DYSEN- TERY, may be carried in the encysted form by Musca domestica and Calliphora erythrocephela according to Flu (1916). Roubaud (1918) has carefully investigated and finds that the free amoeba is quickly digested by the fly, but the cysts may pass readily through the intestines within 24 hours and may be demonstrated up to 40 hours. The cysts die rapidly in dry fly feces, and therefore to live must be placed on moist substances, or on food. Mastigophora: Protomonadina: Bodonidae Prowazekia sp. is found in Fannia canicularis (Dunkerly 1912). Mastigophora: Polymastigina: Polymastigidae Giardia intestinalis (Lambl) (Lamblia), the cause of LAMBLIAN DYSENTERY of rodents and man, may be carried in the encysted form by Musca domestica, according to Roubaud (1918), but must be deposited in the feces on moist substances, or directly on food. Mastigophora: Binucleata: Leptomonidae Crithidia calliphorae Swellengrebel is described as a parasite of Calliphora erythrocephala Meigen.. Crithidia muscae-domesticae Werner is described as a parasite of Musca domestica Linnaeus. Leptomonas calliphorae (Swingle) is a parasite of Calliphora erythro- cephala Meigen. Leptomonas drosophilag Chatton and Alilaire is a parasite of Drosophila confusa. Leptomonas homalomyiae (Brug) is a parasite of Fannia scalaris Fabricius. Leptomonas lineata (Swingle) is a parasite of Sarcophaga sarraceniae Riley. Leptomonas luciliae (Strickland) is a parasite of Lucilia sp. Leptomonas luciliae (Roubaud) is described as a parasite of Lucilia serenissima Walker. Leptomonas mesnili Roubaud is a parasite of Lucilia sp. 118 SANITARY ENTOMOLOGY Leptomonas muscae-domesticae (Burnett) is a parasite of Musca domestica Linnaeus, M. nebulo Fabricius, Fannia scalaris Fabricius, Pollenia rudis Robineau-Desvoidy, Teichomyza fusca Macquart, Lucilia sp., Pycnosoma putorium Wiedemann, Scatophaga lutaria Fabricius, Neuroctena anilis Fallen, Homalomyia corvina Verrall, and Sarcophaga murus, undergoing complete metamorphosis in the bodies of the flies. Patton (1910) has demonstrated that the disease may be transmitted from fly to fly as follows: the food becomes infected from the feces of the infected flies which have fed on it; uninfected flies may become in- fected by ingesting either the long flagellates, the short encysting forms, or the cysts, in the feces of other flies, or in food contaminated by other flies. Leptomonas pycnosomae Roubaud is a parasite of Pycnosoma putorium. Leptomonas roubaudi Chatton is a parasite in the Malpighian glands of Drosophila confusa Staeger. Leptomonas sarcophagae (Prowazek) is a parasite in the gut of Sarcophaga haemorrhoidalis Fuller and another species of Sarcoph- aga. Leptomonas soudanensis Roubaud is a parasite of Pycnosoma putorium. Leptomonas stratiomyiae (Fantham and Porter) is a parasite of Stratiomyia chameleon Linnaeus and S. potamida Meigen. Fantham and Porter (1916) proved it experimentally pathogenic by inoculation to Mus musculus. Leishmania tropica (Wright), the cause of ORIENTAL SORE of man, may be taken up in the crithidial stage by Musca domestica and the organism demonstrated 48 hours after feeding, according to Carter (1909). According to Wenyon (1911) who investigated BAGDAD SORE, Musca domestica may readily feed on the sores and take up Leishmania, but there is no development of the organism and no parasites were found in the feces. On the other hand, Row, working with CAMBAY SORE believed the organism transmissible by Musca domestica up to three hours after the fly had fed on infected sores. He found the gut con- tents of flies infective for a monkey three hours after the fly had taken up Leishmania, but Patton (1912) maintains that Cambay sore never com- mences in a cut, scratch or abrasion, and failed to transmit the disease in this manner in numerous experiments with Musca nebulo and Musca sp. A new investigation, however, is warranted by Row’s statement, seeking fecal infection of wounds. Rhynchoidomonas luciliae Patton is parasitic in the Malpighian tubules of Musca nebulo and Lucilia serenissima. DISEASES BORNE BY NON-BITING FLIES 119 Mastigophora: Binucleata: Trypanosomidae Castellanella evansi (Steel) Chalmers (Trypanosoma) 2, the cause of SURRA, an African disease of horses and other mammals, may be carried by Musca domestica by contact with wounds. Castellanella hippicum (Darling) Chalmers (Trypanosoma),” the cause of MURRINA, a disease of horses and mules in the United States and Panama, may be carried according to Darling (1911, 1912) by Musca domestica, Chrysomya and Sarcophaga, from wounds by mechanical transmission. He ascertained that the trypanosomes remained alive in the proboscis of the fly at least two hours, and he also successfully inocu- lated a mouse with the crushed portions of a proboscis of a fly which had fed on infected blood. Isolation of the animals from fly attack, and bind- ing up of wounds wiped out the epidemic. He did not ascertain whether the trypanosome might pass out of the fly’s feces and contaminate lesions in this manner, which naturally is the normal method of fly transmission. Mastigophora: Spirochaetacea: Spirochaetidae Treponema pertenue (Castellani), the cause of YAWS, an infectious disease of men, may be transmitted by the house fly, Musca domestica. Castellani in Ceylon (1907) found that flies eagerly crowd around the open sores of yaws patients. In the hospitals as soon as the dressings were removed from the yaws ulcerations, they became covered with flies, sucking with avidity the secretion, which they may afterward deposit in the same way on ordinary ulcers on other people. He conducted experi- ments which proved that the flies do take up the organism, which he recov- ered from the dissected mouth parts. He fed flies on the organism, then removed their appendages and fastened them over scarified areas of skin of monkeys, and obtained in two experiments positive lesions by this organism. Robertson (1908) also definitely obtained this spirochaete from flies collected on yaws lesions. Nicholls (1912) ascribes most of the cases of yaws in the West Indies to inoculation of surface injuries by Oscinis pallipes Loew. Sarcophaga is also considered a carrier. None of the experiments have been directed at obtaining infection through the deposition of the spirochaetes, taken up by the fly in feeding, in its feces on other ulcers or injuries. This would appear to be the most likely method of infection. *The classification of the Trypanosomes has recently been modified by Chalmers, including several genera composed of species with similar morphological and_ bio- logical characteristics. 120 SANITARY ENTOMOLOGY Neosporidia: Myxosporidia: Nosemide Nosema apis Zander, a bee disease, may be communicated to Calliphora vomitoria and other insects through feeding on the bee excreta around beehives. Protozoa: Neosporidia: Myxosporidia: Thelohanidae Octosporea monospora Chatton and Krempf is a parasite of Fannia scalaris. Thelohania ovata Dunkerly is also a parasite of Fannia scalaris. HIGHER ORGANISMS CARRIED BY FLIES As pointed out in the introduction of this lecture, flies can carry the eggs of higher organisms. The evidence is presented below, but refer- ence should be made to Dr. Ransom’s lecture (Chapter V). Platyhelmia: Cestoidea: Cyclophyllidea: Taeniidae Taenia (Taeniarhynchus) saginata Goeze, the FAT-TAPEWORM of cattle and rarely of man, has been commonly found in the egg stage in Musca domestica in British East Africa according to Shircore (1916). It is necessary that the eggs, passed in human or animal feces, reach the . food or water of the next host (cattle). This may occur by means of insanitary sewage disposal, possibly under exceptional circumstances by the agency of flies. Platyhelmia: Cestoidea: Cyclophyllidea: Hymenolepididae Choanotaenia infundibulum (Bloch) Cohn, the FOWL TAPEWORM, developed to the cysticercoid stage in Musca domestica fed on the eggs, and Guberlet (1916) succeeded in infecting new-born chicks by feeding them on infected Musca domestica. Davamea cesticillus Molin, a fowl tapeworm, was tested with negative results by Guberlet (1916), using Musca domestica and Calliphora vomi- toria in his search for the intermediate host. Davainea tetragona Molin, another chicken tapeworm, likewise gave Guberlet (1916) negative results with the same two species of flies. Platyhelmia: Trematoda: Malacotylea: Schistosomidae Schistosoma mansoni Sambon, the trematode worm causing intestinal Schistomiasis of man or BILHARZIOSIS, may be found in the egg stage DISEASES BORNE BY NON-BITING FLIES 121 in Musca domestica, according to Shircore (1916), who-recorded eggs of this species in flies in British East Africa. The cercaria stage is passed in a snail. Nemathelminthes: Nematoda: Spiruridae Habronema muscae (Carter) Diesing, a STOMACH WORM OF HORSES, passes its earlier stages in Musca domestica, according to Ran- som (1913). Ejither the egg or first-stage larva is ingested by the fly larva breeding in horse manure. Development goes on within the fly larva and pupa, the last stage being found in the proboscis of the adult fly. It passes to horses through the swallowing of infested flies and probably may also leave the proboscis of the fly while the insect is feeding on the mucous membranes of the horse. Van Saceghem (1917, 1918) placed flies bred from larve fed on infected manure, on skin lesions of a horse and produced infections of EQUINE GRANULAR DERMATITIS, caused by the presence . of Habronema larve in the skin. Habronema microstoma (Schneider) Ransom and H. megastoma (Rudolphi) Seurat have also been shown to pass their developmental stages in Musca domestica. (See Chapter V.) Nemathelminthes: Nematoda: Ascaridae Ascaris lumbricoides Linnaeus, the cause of HUMAN ASCARIASIS, does not require an intermediate host. Stiles in 1889 fed Musca domestica larve on female Ascaris and later found the eggs in different stages of development in both larve and adult flies (Graham-Smith, 1913). Shir- core (1916) in British East Africa found the eggs in the intestines of Musca domestica in nature. Nicholls (1912) in St. Lucia found the eggs in the abdomens of flies, Borborus punctipennis Macquart (Limo- sina), taken at fecal matter. (See Chapter V.) Nemathelminthes: Nematoda: Oxyuridae Oxyuris Curvula Rudolphi, the EQUINE PINWORM, is recorded by Patton and Cragg (1913), as probably the species of Oxyuris, which in Madras is often found in the embryo stage heavily infesting the larve of Musca nebulo. Oxyuris vermicularis Linnaeus, the HUMAN PINWORM, can be ingested in the egg stage by flies, according to Grassi (1883). 122 SANITARY ENTOMOLOGY Nemathelminthes: Nematoda: Ancylostomidae Ancylostoma duodenale Dubini, cause of HOOK WORM disease of man, has been found in the egg stage in house flies, Musca domestica, by Shircore (1916) in British East Africa, and it is therefore possible that the eggs may be placed on food, in which the hook worm larva could hatch and be directly conveyed into the body with the food. No develop- ment takes place in the flies. Necator americanus Stiles, the American HOOK WORM, was collected in the egg stage in the intestines, of Limosina punctipennis in St. Lucia by Nicholls (1912). Galli-Valerio (1905) found that flies could carry on the surface of their bodies not only the eggs but also the larve of this worm. Nemathelminthes: Nematoda: Trichosomidae Trichiuris trichiura (Linnaeus), the WHIP WORM of man, was col- lected in the egg stage by Shircore (1916) in British East Africa in the abdomen of Musca domestica and by Nicholls (1912) in St. Lucia in the abdomen of Borborus punctipennis (Limosina), and the latter succeeded in feeding Musca domestica on the eggs. It probably does not require the flies as immediate hosts, but is undoubtedly distributed in this manner. Thus to the already long list of serious diseases in whose spread the non-blood-sucking flies may play some part we may now add hog cholera, poliomyelitis, amoebic dysentery, Lamblian dysentery, Oriental sore, surra, murrina, yaws, purulent ophthalmia, trachoma, the fat-tapeworm of cattle, the fowl tapeworm, bilharziosis of man, the stomach worm of horses, equine granular dermatitis, human ascariasis (not normal method), equine pinworm, pin itch, two hook worms, and the whip worm, and possibly also smallpox, measles and scarlet fever. We found that the bacteria were only mechanically carried by the flies, except in the case of Bacillus anthracis. Among the protozoa also those organisms parasitic in vertebrates all seem to be mechanically transmitted. The various parasites mentioned, however, pass complete life cycles in the body of the fly. Among the worms, however, there are cases of external mechanical carriage, transmission of eggs through the intestinal canal, retention of the egg from larva to adult fly (Ascaris lumbricoides), and also cases of the fly serving as an intermediate host (Choanotaenia infundibulum, and Habronema spp.). The last named worms are the only organisms known to be transmitted by the fly which work forward into the proboscis for transmission at time of feeding. A bibliography of the works cited in the lecture follows: DISEASES BORNE BY NON-BITING FLIES 123 IMPORTANT GENERAL TEXTBOOKS Fantham, H. B., Stephens, J. W. W., and Theobald, F. V., 1916.—The Animal Parasites of Man. Wm. Wood & Co., New York, 900 pp. Graham-Smith, G. S., 1913.—Flies in Relation to Disease. Non-Blood- Sucking Flies. Cambridge Univ. Press, 292 pp. Herms, Wm. B., 1915.—Medical and Veterinary Entomology. The Mac- millan Company, New York. . Hewitt, C. Gordon, 1914.—The House Fly, Musca domestica Linn. Its Structure, Habits, Development, Relation to Disease and Control. Cambridge Univ. Press, 382 pp. Hindle, Edward, 1914.—Flies in Relation to Disease. Blood-Sucking Flies. Cambridge Univ. Press, 398 pp. Patton, Walter Scott, and Cragg, Francis William, 1913.—A Textbook of Medical Entomology. Christian Literature Society for India, Lon- don, Madras and Calcutta, 764 pp. . Riley, W. A., and Johannsen, O. A., 1915.—Handbook of Medical Entomology. Comstock Publishing Company, Ithaca, N. Y. SPECIAL REFERENCES Cao, G., 1898.—L’Ufficiale San. Riv. D’Igiene di Med. Patr., vol. 11, pp. 331-348, 385-397. Cao, G., 1906A.—Annali D’Igiene Sper., vol. 16, n. s., pp. 339-368. Cao, G., 1906B.—Annali D’Igiene Sper., vol. 16, n. s., pp. 645-664. Carter, R. M., 1909.—Brit. Med. Journ., vol. 2, pp. 647-650. Castellani, A., 1907.—Journ. Hygiene, vol. 7, p. 567. Castellani, A., and Chalmers, A. J., 1913.—Manual of Tropical Medi- cine, 2nd edit., p. 700. Celli, A., 1888.—Bullet. d..Soc. Lancisiana d. Ospedali di Roma, fasc. 1, st. a G. L., Lewis, F. C., and Glynn, E. E., 1912.—Journ. Hygiene. vol. 12, No. 3, pp. 306-309. Darling, S. T.,.1911.—Journ. Infect. Diseases, vol. 8, No. 4, pp. 467- 485. . Darling, S. T., 1911.—Parasitology, vol. 4, No. 2, pp. 83-86. Darling, S. T., 1912.—Journ. Exper. Med., vol. 15, No. 4, pp. 365- 366. Darling, S. T., 1912.—Trans. 15th Internat. Congress Hyg. and Demog., Washington. Davaine, C., 1870.—Bullet. de l’Acad. de Méd., Paris, vol. 35, pp. 471- 498. 124 SANITARY ENTOMOLOGY Dorset, M., McBryde, C. N., Nile, W. B., and Rietz, I. H., 1919.—Amer. Journ. Vet. Med., vol. 14, No. 2, pp. 55-60. Dudgeon, L. S., 1919.—Brit. Med. Journ., No. 3041, April 12, pp. 448- 451. Dunkerly, J. S., 1912.—Central. f, Bakt., Paras, und Infekt., vol. 62, p. 138. . Faichnie, N., 1909.—Journ. Royal Army Med. Corps, vol. 13, pp. 580- 584, 672-675. Fantham, H. B., and Porter, A., 1916.—Journ. Parasit., vol. 2, No. 4, pp. 149-166. Flu, P. C., 1916.—Geneesk. Tijdschr. v. Nederl.-Indie, vol. 56, No. 6, pp. 928-939. Galli-Valerio, B., 1905.—Centralbl. f. Bakt. Orig., vol. 39, p. 242. Graham-Smith, G. S., 1910.—Repts. Local Govt. Bd., on Public Health and Medical Subjects, n. s., No. 40, pp. 1-40. Graham-Smith, G. S., 1912.—Forty-first Ann. Rept. Local Govt. Bd. 1911-12, Suppl. Rept. Medic. Off., pp. 304-329, 330-335. Grassi, B., 1883.—Arch. Ital. de Biol., vol. 4, pp. 205-208. Guberlet, J. E., 1916.—Journ. Am. Vet. Med. Assn., vol. 49, pp. 218- 237. Hofmann, E., 1888.—Correspondenzbl. d. arztl. Kreis- und Bezirks- vereine im Kénigr. Sachsen, vol. 44, No. 12, pp. 130-133. Howard, C. W., and Clark, P. F., 1912.—Journ. Exper. Med., vol. 16, No. 6, pp. 850-859. Leboeuf, A., 1913.—Bull. Soc. Path. Exot., vol. 6, No. 8, pp. 551-556. Ledingham, J. C. G., 1911.—Journ. Hygiene, vol. 11, No. 3, pp. 333- 340. MacGregor, M. E., 1917.—Journ. Trop. Med. and Hygiene, vol. 20. No. 18, p. 207. Macrae, R., 1894.—Indian Med. Gazette, pp. 407-412. Maddox, R. L., 1885.—Journ. Roy. Microsc, Soc., Ser. 2, vol. 5, pp. 602- 607, 941-952. Marpmann, G., 1897.—Centralbl. f. Bakteriol., 1 Abt., vol. 22, pp. 127- 182. Morgan, H. deR., and Ledingham, J. C. G., 1909.—Proc. Roy. Soc. Med., vol. 2, pt. 2, pp. 133-149. Nicholas, G. E., 1873.—Lancet, vol. 2, p. 724. Nicoll, W., 1911.—Journ. Hygiene, vol. 11, No. 3, pp. 381-389. Nicholls, L., 1912.—Bull. Ent. Research, vol. 3, No. 1, p. 85. Nuttall, G. H. F., 1897.—Centralbl. f. Bakteriol., vol. 22, pp. 87-97. Nuttall, G. H. F., 1899.—Johns Hopkins Hospital Reports, vol. 8, Nos. 1-2, pp. 1-154. Patton, W. S., 1910.—Bull. Soc. Path. Exot., vol. 3, pp. 264-274. DISEASES BORNE BY NON-BITING FLIES 125 Patton, W. S., 1912.—Sci. Mem. Officers Med. & Sanit. Dept., Govt. India, No. 50, 21 pp. Ransom, B. H., 1913.—U. 8S. Dept. Agr., Bur. Anim. Ind., bull. 163, pp. 1-36. Robertson, A., 1908.—Journ. Trop. Med. and Hygiene, vol. 11, p. 213. Rosenau, M. J., 1916.—Preventive Medicine and Hygiene, pp. 206-252. Roubaud, E., 1918.—Bull. Soc.’ Path. Exot., vol. 11, No. 3, pp. 166- 171. Sawtchenko, J. G., 1892.—Review in Ann, Inst. Pasteur, vol. 7. Scott, J. R., 1917.—Journ. Med. Research, vol. 37, No. 164, pp. 115, 121-124, Shircore, J. O., 1916.—Parasitology, vol. 8, No. 3, pp. 239-243 Simmonds, M., 1892.—Deutsch. med. Wochenschr., No. 41, p. 931. Spillman and Haushalter, 1887.—Compt. Rend. Acad. Sci., vol. 105, pp. 352-353. Tebbutt, H., 1913.—Journ. Hygiene, vol. 12, pp. 516-526. Tizzoni, G., and Cattani, J., 1886.—Centralbl. f. d. med. Wissensch., Berlin, pp. 769-771. Torrey, J. C., 1912.—Journ. Infect. Diseases, vol. 10, No. 2, pp. 169- 176. Uffelmann, J., 1892.—Berliner klin. Wochenschr., pp. 1213-1214. Van Saceghem, R., 1917.—Bull. Soc. Path. Exot., vol. 10, p. 726; 1918, vol. 11, p. 575. Wayson, N. E., 1915.—U. S. Public Health Service, Pub. Health Repts., vol. 29, No. 51, pp. 3890-3393. Welander, 1896.—Wien. klin. Wochenschr., No. 52. Wenyon, C. M., 1911.—Kala Azar Bull. vol. 1, No. 1, pp. 36-58, Yersin, A., 1894.—Ann. Inst. Pasteur, vol. 8, pp. 662-667. CHAPTER VIII Important Phases in the Life History of the Non-Biting Flies * W. Dwight Pierce In the preceding lecture there was brought together an accumulation of evidence against the common flies that frequent our houses which should convince any one of the absolute necessity of: keeping flies from our food, our houses and our bodies. We can only hope to accomplish this object by becoming familiar at least with the more important features in the life history of the flies. From the study of the transmission of diseases we may pick out for example a few points in the biology which need to be stressed, such as feeding habits, regurgitation of food, excreta, breeding places, oviposition, flight, attraction to odor: We are dealing in this lecture not only with the common house fly but also with most of the common flies which frequent our houses and are known as domestic flies. Of the common household flies, only one, the bit- ing stable fly, Stomoxys calcitrans, is omitted for future discussion. Students would do well to examine some book in which the different species are illustrated, so as to become familiar with the characteristic markings. It will then be a good plan to collect the various flies around the house and determine their species. Fairly good illustrations of common household flies. are given by Howard and Hutchinson (1915), and Richardson (1917). The best illustrations of the flies are contained in Patton and Cragg’s textbook (1913). Tables to species of common flies and also illustrations are presented by Riley and Johannsen (1915). It is also desirable to know how to identify the fly larvae when found. The best American work on this subject is by Banks (1912). See also Riley and Johannsen, p. 315. For general information on the life history, morphology, and anatomy of the house fly refer to Hewitt (1917). The flies are classified largely on the characters of the proboscis, antenne, wing veins, eyes and the arrangement of hairs. The larve are classified on the characters of the spiracles, the cephalo-pharyngeal skeleton, tubercles, hairs and processes. +This lecture was read July 22 and distributed July 29, 1918. 126 PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 127 HOUSE FLY, MUSCA DOMESTICA LINNAEUS 2 (See Frontispiece ) The common house fly, Musca domestica, is that insect charged with _the carriage of the greatest number of diseases, and probably justly, be- cause of its frequentation of all types of excreta, garbage and waste, its common visitations to places where foods are handled, and also its visits to the human body. We have shown in the preceding lecture how it and its allies can carry disease and what diseases are charged against each. Now we will take a brief review of its life history in order to arrive at important data for handling its control. The house fly adult is yellowish to dark gray in color, with four equally broad longitudinal stripes on the thorax; first three abdominal segments yellowish with a central black stripe and with two less distinct discal stripes. The males measure 5.8 to 6.5 mm. in length, and_ the females 6.5 to 7.5 mm. The eyes in the male are nearly contiguous and in the female are widely separated. This fly has been distributed by commerce to almost all parts of the civilized world. Certain features of its anatomy are of interest in the present study. The head is prolonged to form a proboscis which is enlarged at tip into the haustellum bearing apically the oral lobes or labella. These lobes bear a large number of channels kept open by incomplete chitinous rings called pseudotracheae, which are fully described by Graham-Smith (1913). The proboscis of the house fly is adapted to sucking and the absorption of liquid or liquefied food. It cannot take up very large particles of solid food. Nicoll (1911) found that the flies could not ingest particles larger than .045 mm. This therefore determines the size of worm eggs which can be ingested by the adult. We must assume therefore that when flies contain larger eggs, these were taken in by the larva. Normally, however, the food must pass between the bifid extremities of the chitinous rings of the pseudotracheal channels and pass along these to the mouth. These openings measure from .003 to .004 mm. in diameter. Solid par- ticles, however, are heaped up in a slight ridge in the channel between the oral lobes and are probably sucked into the oral pit and into the mouth. When the fly feeds on dry substances such as sugar, dried specks of milk, or sputum, etc., it first liquefies the substance by a salivary secre- tion which flows into the oral pit and onto the substance, being dis- tributed by the pseudotracheal channels. The moistening is also aided » An appeal has been made to the International Commission for Zoological Nomen- clature for the retention of Musca in this sense with domestica as type. 128 SANITARY ENTOMOLOGY by the regurgitation of food from the crop, as proven by Graham-Smith, who fed flies upon carmine colored food, and found carmine stains on semi-fluid material upon which these flies later fed, for 22 hours. The intestinal canal is composed of pharynx, esophagus, crop, pro- ventriculus, ventriculus or chyle stomach, proximal and distal intestine and rectum. The esophagus passes from the pharynx through the cer- vical region into the thorax, in the anterior part of which it opens into the proventriculus, and from this same point a duct which is continuous with the esophagus passes back into the abdomen to the crop which is a bilobed sac, capable of considerable distention. This crop serves as a food reservoir. The fly feeds until it has engorged the crop, and often will continue feeding, the food then passing directly into the proventri- culus. The opening of the proventriculus into the esophagus is ventral. This organ is circular, flattened dorsoventrally. The ventriculus is tubular, narrowest in front and narrowing again in passing through the thoraco-abdominal foramen. The proximal intestine is the longest region of the gut, being considerably coiled. The distal intestine begins at the entrance of the Malpighian tubules, and is only curved once. It is sep- arated from the rectum by a valve. The rectum is composed of three parts, the intermediate of which is swollen to form the rectal cavity into which the four rectal glands empty. Food may remain in the crop for several days, and even when no further food is given, it requires many hours to empty the crop com- pletely. After feeding the fly usually retires to a quiet spot and cleans its head and proboscis. It frequently regurgitates its food from the crop in the form of large drops of liquid which are subsequently slowly drawn up again and probably pass into the proventriculus. These drops of regurgitated food frequently are deposited, often for the purpose of moistening sugar and similar dry foods. We may now see how easy it is for a fly which has fed on infected substances to contaminate other substances for days by regurgitation from the crop, as well as through fecal deposits. Experimental evidence has proven contamination by both the feces and the vomit. The fly’s body is externally constructed so as to further aid in disease carriage. There are numerous hairs or sete on the body, espe- cially on the legs. The last joint of the tarsus of each leg bears two claws and a pair of membranous pyriform pads or pulvilli. These pulvilli are covered beneath with innumerable, closely set, secreting hairs by means of which the fly is able to walk in any position on highly polished sur- faces. These sucker-like pads or pulvilli and the sete of the legs are excellent bacteria carriers, and not infrequently larger organisms as mites, worm eggs, etc., are thus carried. The sexes of the house fly are about equal in number. Copulation PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 129 may take place, according to Hutchison (1916), as early as the day following emergence. Oviposition may begin on the third day. He cites a large series of observations on the preoviposition period showing that eggs may be laid from 21% to 23 days after emergence, and that the period corresponds to temperature and humidity changes. At Washington the shortest period was obtained at 82° to 84° F., and in general the length of period increased with the decrease of temperature. Increase in humidity seems to hasten egg laying. The eggs are white, cylindrically oval, slightly broader at the pos- terior end with two distinct curved rib-like thickenings on the dorsal surface, along one of which the egg splits on hatching. These eggs are laid in masses averaging about 120, and a female may lay as many as four such batches, and probably under favorable conditions more. The eggs usually hatch in less than 24 hours, the time of course depending upon the climatic conditions. At 10° C. (40° F.) the egg period is two or three days; at 15 to 20° C. (59-68° F.) it is 24 hours; at 25-35° C. (77-95° F.) only 8 to 12 hours, according to Hewitt (1917). The larve are white, smooth, cylindrical maggots, tapering at the head end and considerably enlarged at the tail end. When viewed by trans- mitted light a dark chitinous structure can be seen in the anterior regions. This is called the cephalopharyngeal skeleton and is partially extrusible. Each species of fly larva is distinguished by the form of this skeleton and hence if a slide mount is made of a skin boiled in potash, the species can be identified by this and one or more other characters. The three larval stages differ somewhat in the form of this skeleton so that it becomes possible to determine exactly the stage of development. The body is composed of fourteen segments of which the second is the pro- thorax. This segment at its posterior margin bears the anterior spiracles which are fan-shaped and have six or seven lobes. This segment is fol- lowed by the mesothorax, metathorax, and eight abdominal segments. The ninth and tenth (anal) segments are small and ventral. The anterior portion of the venter of each of the first eight abdominal segments bears spiniferous pads which assist in locomotion. The eighth or last apparent segment bears the spiracular plates. These spiracular plates afford the best means of identification of fly larvae. In the first two stages each plate consists merely of two oblique slits on a slight prominence. In the third stage they are well defined plates, D-shaped, closer together than their width, with flat faces opposed, each with three sinuous slits. In connection with this larval description, we may call attention to errors existing in many larval descriptions. The thoracic spiracles belong to mesothorax but often appear to have migrated to the prothorax. The large terminal spiracles of Dipterous larve are always on the eighth 130 SANITARY ENTOMOLOGY segment, as in almost all orders of insects. The ninth and tenth seg- ments are apt to be small and obscure and center around the anus, which belongs to the tenth. The larval period varies in response to climatic stimuli, but under favorable conditions is about four days in length. When full grown the larva varies from 10 to 12 mm. in length. Pupation takes place within the last larval skin which shrinks and hardens to form a reddish case or puparium. This period lasts from 3 to 10 days. When the fly is ready to emerge it pushes off the cap or head end. The entire developmental period may require from eight to eighteen or more days. Kisliuk has found pupae of the fly in manure piles at various times during the win- ter, which of course indicates that the developmental period may occupy an entire winter if the pupa is caught by cold weather. Bishopp, Dove and Parman found that adults emerged from immature stages which had been in manure for six months. Hutchison’s observations at Washington, D. C., confirm these findings. The adult flies are capable of considerable flight. Parker demon- strated a migration of two miles in his Montana studies. Bishopp and Laake (1919) record the flight of marked house flies of thirteen miles. In this connection the most interesting contribution is that of Ball (1918) in which he shows that house flies apparently migrated with the wind from 46 to 95 miles from mainland to a tiny island. The house fly has been found breeding in horse manure, human excre- ment, and hog manure very freely and to some extent in cow and chicken manure. It lays its eggs in a great variety of decaying animal and vegetable materials, such as slops, spent hops, moist bran, ensilage, rotting potatoes, dead animals, excreta-soiled straw, paunch contents of slaughtered animals, soiled paper and rags, etc. THE BLUE BOTTLE FLIES OF THE GENUS CALLIPHORA 3 The large blue bottle fly, Calliphora vomitoria Linnaeus (plate I, fig. 1) and its near relative C. erythrocephala Meigen are often found in houses. These flies have also been shown to be dangerous insects because of their ability to transmit disease. In fact they are much more likely to directly transmit disease organisms than the house fly because of their habits of breeding in flesh which gives them also the name blow flies. The adults are grayish on the thorax and dark metallic blue with sug- gestions of silver on the abdomen. In vomitoria the gene are black and beset with golden red hairs, while in erythrocephala the gene are fulvous to golden yellow and beset with black hairs. 3 An appeal has been made to the International Commission for Zoological Nomen- clature for the retention of Calliphora in this sense with vomitoria as type. PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 131 These flies are necrophagous and deposit their eggs upon any fresh, decaying or cooked meat, and upon dead insects; they breed occasionally in human excrement and sometimes will deposit their eggs in open flesh wounds. On the battle fronts of Europe and Asia where the wounded lay for long periods and where many dead bodies remained uncared for, these flies multiplied to tremendous numbers and were largely responsible for the carrying of infections to wounds. When a fly lays its eggs in living flesh and the larve develop therein, the infection is called myiasis. This subject is of such importance that two entire lectures is devoted to it (Chapters XII and XIII). Important as they are, the blow flies are usually subordinated to the house fly in the discussion of dangerous flies, but thorough investi- gations of these species are more than likely to greatly increase their standing as disease carriers. The eggs are deposited in masses of as many as 300 and a single fly may possibly deposit three batches. They hatch in from 10 to 24 hours after deposition. The larve of C. erythrocephala may be distinguished from the house fly larve by having usually nine but sometimes up to twelve lobes in the anterior (thoracic) spiracles; an anterior scabrous swollen ring on each of the first eight segments of the abdomen, and a ventral groove on each segment beneath; the stigmal field concave, surrounded by three pair of tubercles above, and two large and one small pair below; the stigmal plates about once and a fourth their diameter apart, each with three straight slits, directed principally toward the opposite plate; and also, by having an anal pair of tubercles. The larval characters are illustrated by Hewitt and also by Banks. The larval period requires seven and a half to eight days at 23° C. (73.5° F.) and the pupal period fourteen days, according to Hewitt. Bishopp and Laake found the larve to attain full growth in three to four days and the time from deposition of eggs to emergence of adults was 15 to 20 days. THE SHEEP MAGGOTS OR GREEN BOTTLE FLIES The European sheep maggot fly, Lucilia sericata Meigen, is primarily an outdoor fly but occasionally is found indoors, especially in farm and country houses. It ‘is more brilliant than the Calliphoras, being of a burnished gold with a shining, bluish-green color. The flies are strongly attracted to meat and carcasses in which they lay their eggs. They also occur on human and animal excrement. The larve breed readily in all these substances. In Europe the flies very commonly lay their eggs in matted wool and on the flesh on the backs of sheep, and the larve 132 SANITARY ENTOMOLOGY breed in the flesh causing external myiasis. This species attacks ulcers and sores of men and animals. Its most common attack on sheep and calves is made on the soiled rumps of animals suffering from diarrhea. No doubt the flies also serve as distributors of the diarrhea. The larva has eight-lobed anterior spiracles. The same number of tubercles margin the stigmal plate behind as in Calliphora, but they are smaller and sharper. The stigmal plates are about one-half their diameter apart, each with three straight slits, directed somewhat toward each other, but also downward. Undoubtedly under battle front conditions this fly can be expected to visit human wounds and breed in them even more readily than Cal- liphora. It has been shown by Cao to transmit anthrax with equal ease. Several other species of Lucilia have like habits, and the larve of two of these, L. caesar Linnaeus (not sericata Meigen), and L. syloarum Meigen have been described and illustrated by Banks. The larvae of L. caesar measure 10 to 11 mm. in length and have not adequately been separated from Calliphora erythrocephala. The larval period averages about fourteen days and the pupal stage about the same. Bishopp and Laake state that in Texas, during warm weather, the larval period ranges from three to twelve days, the pupal stage five to sixteen days and the total developmental period eleven to twenty-four days. This fly is illustrated in plate I, Fig. 2. OTHER SCREW WORMS AND BLOW FLIES The question of myiasis, which covers screw worms and blow flies, is to be considered in separate lectures (Chapters XII and XIII), but mention must be made of them at present because undoubtedly many infectious diseases are carried by these insects which attack alike live flesh through wounds, and dead animals. I would hardly hesitate to claim that probably all such flies may carry anthrax at least, and probably do carry other diseases. Bishopp, Mitchell, and Parman (1917) describe quite fully the habits of the common American screw worm, Chrysomya macellaria Linnaeus * (plate I, fig. 3, plate IT) which breeds in both carcasses and flesh wounds (plate IV). They also treat the black blow fly Phormia regina Meigen (plate I, fig. 4), and other species. The large hairy blow fly, Cynomyia cadaverina, Robineau-Desvoidy, and the gray flesh flies Sarcophaga texana Aldrich, S. tuberosa var. sarracenioides Aldrich, §. sarraceniae *An appeal has been made to the International Commission on Zoological Nomen- clature to retain Chrysomya in the sense with macellaria as type. PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 133 Puate I.—Screw worms and blow flies. Fig. 1 (upper left).—The blue bottle fly, Cal- liphora vomitoria, Fig. 2 (upper right).—The green bottle fly, Lucilia caesar. Fig. 3 (lower left).—The American screw worm, Chrysomya macellaria. Fig. 4 (lower right).—The black blow fly, Phormia regina. (Howard and Pierce, photos by Dovener.) : 134 SANITARY ENTOMOLOGY Pirate II.—Eggs of the American screw worm, Chrysomya macellaria, on meat. (Bishopp.) PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 135 Riley (plate II, fig. 1) and S. robusta Aldrich are also among the most, common flesh flies. Froggatt (1915) has given a very fine treatment of the most impor- tant sheep maggot flies and has presented colored illustrations of some of them. All of these flies are likely to be found in houses and markets and when given the opportunity will lay eggs on meat offered for sale or exposed in kitchens or mess halls. If this meat is already cooked there is a good chance of the eggs being ingested and giving rise to gastrointestinal | myiasis. But the danger from flesh flies is greater than the mere causation of external or internal myiasis. The flies which lay the eggs may have bred in diseased carcasses, and if so, probably will deposit with the eggs a glutinous film containing bacteria from these carcasses, for it will be remembered that the fly larva takes up these bacteria and they may remain in its body until it as a mature fly lays its eggs, and even longer. It must be borne in mind that because conditions in the imme- diate vicinity are sanitary, does not mean that the flies which come are sanitary, because Bishopp and Laake (1919) record the flight of marked Chrysomya macellaria flies for 15 miles, and of Phormia regina for 11 miles. OTHER EXCREMENT BREEDERS Others of our house flies, as the non-biting stable fly, Muscina stabulans Macquart (plate III, fig. 2), the lesser house fly Fannia cant- cularis Linnaeus (plate III, fig. 3), and the latrine fly F. scalaris Fabricius breed in decaying vegetables and animal matter. Muscina stabulans looks very much like the house fly, but it is a little more robust. It is gray and the thorax is marked with four longitudinal black lines. Parts of the legs and scutellum are reddish. The principal differential character is in the wing venation. The larva, however, is easily distinguished from Musca domestica, by the six-lobed anterior spiracles and the anal stigmal plates scarcely elevated, less than their diameter apart, each with three very short slits pointing towards those of the opposite plate. It breeds in decaying and live vege- table matter, human and animal excreta, and has even been reared from insect puparia. It breeds likewise in raw and cooked meats and on car- casses. It is therefore a very potential disease carrier, possessing all the opportunities of the house fly, with which it may already be mixed in medical literature. Fannia canicularis and F. scalaris are two flies commonly found in houses, which greatly resemble the house fly, but the former may be dis- tinguished by the presence of only three dark stripes on the thorax instead of the four found in the house fly. The larve of these flies are very 136 SANITARY ENTOMOLOGY Prate III.—Flies with dangerous habits. Fig. 1 (upper left)—A flesh fly, Sarcophaga jajaja ya sarraceniae. Fig. 2 (upper right). —The non-hiting stable fly, Museina stabulans.is.18.18.18 Fig. 3 (lower left).—The lesser house fly, Fannia canicularis. Fig. 4 (lower erererei right).—The brilliant green fly, Pseudopyrellia cornicina. (Howard “and Pierce, 'e,'e, 'e,'€ photos by Dovener.) PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 137 readily separated by the large number of processes on all the seg- ments. The posterior spiracles are located on raised processes and are not plates as in the species mentioned above. In F. canicularis there are four lobes to the posterior spiracles and six finger-like lobes to the anterior spiracles (see Hewitt, 1917) (see figs. 14 to 19). These flies breed in excrement, and in all kinds of decaying vegetable matter and are often found in cases of intestinal myiasis. REFERENCES Ball, S. C., 1918.—Migration of Insects to Rebecca Shoals Light Station and the Tortugas Islands, with Special Reference to Mosquitoes and Flies. Carnegie Inst., Washington, Publ. 252. Banks, Nathan, 1912.—The Structure of Certain Dipterous Larve with Particular Reference to Those in Human Foods, Bishopp, F. C., 1915.—Flies Which Cause Myiasis in Man and Animals. Some Aspects of the Problem. Journ. Econ. Ent., vol. 8, pp. 317- 829. Bishopp, F. C., and Laake, E. W., 1919.—The Dispersion of Flies by Flight. (Abstract) Journ. Econ. Ent., vol. 12, pp. 210-211. Bishopp, F. C., Mitchell, J. D., and Parman, D. C., 1917.—U. 8. Dept. Agr., Farmers’ Bull. 857. Froggatt, W. W., 1915.—Sheep Maggot Flies. meee Agr., New South Wales, Farmers’ Bull. 95. Graham-Smith, G. S., 1913.—Flies in Relation to iyieaie: Non-blood- sucking Flies. Cambridge Univ. Press. Hewitt, C. G., 1917.—The House Fly. Cambridge Univ. Press. Howard, L. O., and Hutchison, R. H., 1915.—House Flies, U. S. Dept. Agr., Farmers’ Bull. 679. Hutchison, R. H., 1916.—U. S. Dept. Agr. Bull. 345. Nicoll, W., 1911.—_Journ. Hygiene, vol. 11, No. 3, pp. 381-389. Parker, R. R., 1916.—Dispersion of Musca domestica under City Condi- tions in Montana. Journ. Econ. Ent., vol. 9, pp. 325-354. Patton, W. S., and Cragg, F. W., 1913.—A Textbook of Medical En- tomology. Richardson, C. H., 1917.—The Domestic Flies of New Jersey. New Jer- sey Agric. Exp. Sta., Bull. 307. Riley, W. A., and Ji channeen: O. A., 1915.—Handbook of Medical Entomology. CHAPTER IX Common Flies and How to Tell Them Apart ! C. T. Greene Only a few of the very common flies have been included in this chap- ter; the flies that are likely to appear near any house or in any camp. All of them may be attracted by the odors of fresh and cooking foods. In the following pages are presented two tables, one to separate the dif- ferent species of the adult flies, and the other to separate the different larve or maggots’ of the flies. All the terms for the different parts of the flies and maggots have been made as plain as possible so that the Suctoria! type. B JHING Aype. Moure FARTS. Fic. 10.—Mouth parts of flies: a, Suctorial type; 6, biting type. (Greene.) tables can be used by a non-entomologist. In the first table for the adult flies is given the style of the mouth-parts (see fig. 10), that is, whether they are adapted for biting or are simply suctorial, then the common name is given, and then the scientific name. In the second table the larve or maggots can be separated into different species. Under the name of each species, the larva or maggot is described in further detail and here mention is made as to where the species will breed. 1This lecture was presented September 9, and issued September 11, 1918. It has been somewhat modified. 138 COMMON FLIES AND HOW TO TELL THEM APART 139 All the Sarcophagid or “flesh flies” can be readily separated from all the other flies in the following table because their bodies are entirely gray. The head is rather a bright red, the top of the back has three parallel dark stripes and the top of the abdomen has lighter reflecting areas, giving it somewhat of a checkered appearance. \ TABLE TO SEPARATE THE ADULT FLIES I. Grayish flies with from two to four longitudinal stripes more or less indicated on the thorax. 1. Dark gray, medium sized fly; top of thorax with four parallel, black stripes; sides of abdomen with a large yellow area (variable in size and never definitely outlined); mouth-parts of the suc- torial type (see fig. 10a), never for biting; variable in size but MTUSCA DOMESTICA L Fic. 11.—Diagrammatic sketch of the house fly, Musca domestica. (Greene.) average about one-quarter inch in length. The common house fly (Frontispiece, figs. 11, 12a) also called typhoid fly. Musca domestica Linnaeus. 2. Brownish-gray fly, slightly larger and broader than the house fly. ~ Top of thorax with two long, parallel, black stripes and on each side of these is a large black dot, below which is a black stripe about half as long as the two long stripes. Abdomen with two or three cone-shaped dark brown spots in the center and two or three round spots on each side (fig. 12c). Mouth-parts piercing or biting type (fig. 10b). Stable fly, also called biting house fly (fig. 46). Stomoays calcitrans Linnaeus. 8. Very dark gray fly, smaller and more slender than the house fly. . Abdomen pointed and more conical in shape. Yellow spots on the sides definitely outlined (fig. 12b). Mouth-parts are of the suc- torial type (fig. 10a). The small house fly (plate III, fig. 3). Fannia canicularis Linnaeus. 4. Gray fly, a little larger than the house fly. (About the size of Stomoxys calcitrans.) Top of thorax has two short, black 140 SANITARY ENTOMOLOGY stripes. Joints of legs reddish at base. Abdomen is gray and in certain lights there are paler gray areas which look like spots but there are never any definitely outlined spots. Mouth- parts suctorial type (fig. 10a). Another stable fly (plate III, fig. 2). Muscina stabulans Linnaeus. II. Bluish, or greenish flies. 1. Large blue fly, with grayish thorax (average length three-eighths to seven-sixteenths of an inch). This fly is rather broad and robust and in certain lights the abdomen shows paler, reflecting areas but not definite spots. Mouth-parts suctorial type (fig. 10a). The common blow fly. Lower part of head (cheeks) red- dish and the beard black. Calliphora erythrocephala Meigen. A slightly larger fly than the preceding but more shiny and a deep greenish blue. Abdomen slightly more pointed and of an a. b House Fir Lirree House Fly STABLE Fly Musca oomesrica.l FANNIA CANT CULARIS.L. STOMOXYS CALCITRANS: Fic. 12—Abdominal markings of three common house flies: a, the house fly, Musca domestica; b, little house fly, Fannia canicularis; c, stable fly, Stomowys calcitrans. (Greene.) In these diagrams the relative size of the abdomen is shown. The light areas in a and b represent yellow markings and are variable in size. In fig. ce the markings of the last segment may be present or absent. even coloration (no reflecting spots). Mouth-parts suctorial type (fig. 10a). Lower part of head black and the beard red. An- other blow-fly (plate I, fig. 1). Calliphora vomitoria Linnaeus. Much smaller fly, shiny green with a decided whitish bloom on the thorax and abdomen. Mouth-parts suctorial (fig. 10a). A green bottle fly. Lucilia sericata Meigen. A slightly smaller fly, shiny, metallic green with a decided bluish tinge and no white bloom. Mouth-parts suctorial (fig. 10a). Green bottle fly (plate I, fig. 2). Lucilia caesar Linnaeus. A dark green fly, little larger than the above species. It is shiny with bluish tinge. Top ef thorax with three dark longitudinal stripes. Thorax often has a bronze tinge. (Average length five- sixteenths to three-eighths of an inch.) Mouth-parts of the suc- torial type (fig. 10a). The “screw-worm fly’? (plate I, fig. 3). Chrysomya macellaria Fabricius. COMMON FLIES AND HOW TO TELL THEM APART 141 6. Deep, shiny blue fly often with a blackish tinge (about five-six- teenths of an inch in length). Mouth-parts of the suctorial type (fig. 10a). The black blow fly (plate I, fig. 4). Phormia regina Meigen. III. Ashen gray to deep gray flies. Top of thorax with three blackish, longitudinal stripes. The abdomen has lighter gray reflecting spots (in certain lights). The different species vary in size from a small fly up to a half inch in length. Mouth-parts are of the suctorial type (fig. 10a). Flesh flies (plate III, fig. 1). Sarcophagidae. THE LARVAE OR MAGGOTS There is a considerable number of flies whose larve or maggots either regularly or-occasionally live in substances used by man as food. The great majority pass through the intestinal’ tract without our knowledge, for most of them cause little or no trouble. Many dipterous larve occur in decaying fruits and vegetables and on fresh and cooked meats. The blow fly, for example, will deposit on meats in a pantry; while other maggots occur in cheese, etc. Pies and puddings in restau- rants are often accessible and very suitable places for flies to deposit their eggs and no doubt a great many maggots are swallowed in this way. The occurrence of dipterous larvae in man is known as “myiasis.” Various names or divisions are given, as “myiasis externa” or “myiasis dermatosa” for larve in the skin or wounds; “myiasis intestinalis” for those in the alimentary canal; and “myiasis narium” for larve in the nose. The presence of larve in the nose is rather accidental in this country and usually due to the “screw-worm.” In tropical countries this type of myiasis is quite common. The larvae of the ox-warble or bot-fly (Hypoderma lineata Villers) sometimes occur in man. There are various cases recorded, mostly of children, where, in the winter time, a larva is observed under the skin, usually in the neck or shoulders, and upon removal proves to be the larva of the heel fly in the second stage. Bot infestation is sometimes called “creeping worms,” and many cases have been recorded by army surgeons on the Mexican border. These cases are probably contracted by men sleeping in stable yards. Descriptions of larvae or maggots * All the larvae mentioned here are broadest near the tip or tail of the body, and taper forward to the head. 2In the following discussion ‘the visible body segments are numbered from head to anus irrespective of their scientific nomenclature.—W. D. Pierce. 142 SANITARY ENTOMOLOGY The larva is divided into fourteen parts, of which eleven are distinct, called segments, and the first segment is the head. The head appears to be bilobed, or divided into two parts when viewed from above, and each lobe bears a minute cylindrical tubercle or papilla (fig. 13). Below is the mouth opening; at one side and above it is the pair of mandibles or great hooks (fig. 13). The second segment or prothorax bears on each side, in the full grown larve, a short fan-shaped process called the an- terior spiracle. The eleventh body segment which might be taken for the last is often a fusion of the seventh to tenth abdominal segments. The eighth abdominal segment can always be identified by the stigmal plates Stigmal field (containing posterior stigmal plates) Paptlls gue tubercle. Ventra/, (fusiform area, Latera/, (fusiform ared. 2 S x Anterior spiracle. Re % g Fic. 13.—Characters of a muscid fly larva. (Greene.) Segment 1 is the head; 2-4 are thoracic segments; 5-11 are abdominal. Segment 11 really contains the seventh to tenth abdominal segments, the spiracles being on the eighth, the anus in the tenth. or lobes. The ninth and tenth are usually small and ventral and enclose the anus. For further details see fig. 13. Table to Separate the Larvae (Maggots) I. Spiny larve. 1. A larva with the body flattened; down the middle of the back are two rows of spines or processes, there are also two rows along the under side and a single row of spines along each side. These spines or processes are pointed and covered with many bristles. There are also two stigmal plates on top of the last segment. (Figs. 14-16.) Fannia canicularis. 2. The larve of Fannia scalaris are similar (figs. 17-19), but the processes have fewer side branches. II. Smooth larve. A. With.one great mouth-hook; slits in stigmal plate winding. 1. Body broadly rounded at rear end, without spines. Stigmal plate with three winding slits (figs. 20 to 22). Musca domestica. COMMON FLIES AND HOW TO TELL THEM APART 143 2. Body same as above species, stigmal plate with three S-shaped slits (figs. 23, 24). Stomoxys calcitrans. B. Two great mouth-hooks; slits in stigmal plate not winding. 1. Body slightly rounded at rear end, faintly spined and with three short, pointed slits in stigmal plate (figs. 25, 26). Muscina stabulans. Fic. 14.—Larva of the little house fly, Fannia canicularis. Greatly enlarged. (Howard and Pierce, drawing by Bradford.) Fic. 15.—Dorsal view of eighth abdominal Fic. 16—Ventral view of terminal seg- segment of the larva of Fannia canic- ments of Fannia canicularis; thé ninth ularis. Very highly magnified. (Draw- and tenth segments are comprised in the small zone around the anus. Very highly magnified. (Drawing by Brad- ford.) ing by Bradford.) 2. Stigmal plates wide apart, each with three straight slits nearly transverse to the body and a distinct button (figs. 27, 28). Calliphora erythrocephala. Calliphora vomitoria. 8. Stigmal plates about half their diameter apart, each with three straight slits directed somewhat downward (fig. 31). Lucilia sericata. 4, Stigmal plates less than their own diameter apart, each with three straight slits pointed downward; no button (figs. 29, 30). Chrysomya macellaria. 144 SANITARY ENTOMOLOGY 5. Stigmal plates at bottom of a deep pit; each plate has three slits pointing downward, plates less than their diameter apart; no button, Sarcophagidae. ‘ Fannia canicularis Linnaeus and Fannia scalaris Fabricius These larve are brownish yellow in color. The body is quite flattened, narrow and pointed in front. The peculiar spines or projections on the body will separate them from the other species. The larva averages nearly three-eighths of an inch in length (figs, 14-19). (See Chapter VIII.) Fie. 17.—Larva of Fannia scalaris, the latrine fly, greatly magnified. (Howard and Pierce, drawing by Bradford.) Fic, 18.—Dorsal view of eighth abdominal Fic. 19—Ventral view of terminal seg- segment of the Fannia scalaris. Very ments of Famnnia scalaris; the ninth highly magnified, (Drawing by Brad- and tenth segments are comprised in ford.) , the small zone around the anus. Very highly magnified. (Drawing by Brad- ford.) Since the larve of this genus feed on fruit and vegetables that are just beginning to decay, one can readily see that they are often swallowed by people. There are many records of the passage of larve or maggots of this genus. At least some species of this genus breed in human feces, therefore they may be possible conveyers of disease. Musca domestica Linnaeus e The larva of the house fly is slender and tapering in front and large and somewhat rounded behind. From above, the head is divided into two COMMON FLIES AND HOW TO TELL THEM APART 145 parts with a tiny papilla on each side (fig. 20) and there is but one great hook. The anterior spiracles (fig. 21) show six or seven lobes; on the under side of the sixth and following segments there is a trans- verse, swollen area, wider in the middle and somewhat pointed toward each end. These areas are provided with minute teeth. The area is slightly prominent and shows two approximate processes. The stigmal field is barely if at all concave and not outlined by tubercles; the posterior spiracles (fig. 22) are prominent, less than their own diameter apart and each with three winding slits and a button at the base. In some cases two of the winding slits are apparently connected. The second- stage larve has two straight slits in each stigmal plate, while in the first larval stage there are two smaller slits on a tubercle each side of the Fic. 20 (left).—Larva of Mlusca domestica; dorsal view of head and porthorax. (Greene. ) Fic. 21 (center)—Larva of Musca domestica; lateral view of terminal segments. (Greene.) The spiracles are located on the eighth abdominal segment. The ninth and tenth segments are ventral and not very distinct, enclosing the anus. Fic. 22 (right)—Larva of Musca domestica; enlarged sketch of right stigmal plate. These plates are less than their breadth apart. (Greene.) middle and in this stage there are no anterior spiracles. (See Chapter VIII.) . The larva of the house fly is rarely swallowed, but there are records to that effect. It sometimes breeds in decaying fruits and vegetables. The principal breeding place is in horse manure. It also breeds in human excrement and because of this habit it is very dangerous to human beings. Stomorys calcitrans Linneus The larva of this species is very similar to that of the house fly, with a single great hook; the anterior spiracles have five lobes (fig. 23); the sixth and following segments have each an area on the under side pro- vided with tubercles; this area is wider in the middle; anal area has two submedian tubercles and three each side of these; above them is a row 146 SANITARY ENTOMOLOGY of minute granules, ending each side in a larger granulate tubercle; there are no tubercles outlining the stigmal field; the stigmal plates are sub- triangular, about one and one-half times their diameter apart, black, and each with three pale areas containing an S-shaped slit (fig. 24). These slits are never near each other like in the house fly, and there is no apparent button. This larva commonly breeds in manure of various kinds, but also in Fie. 23.—Larva of Stomowys calcitrans: enlarged sketch of thoracic spiracles. (Greene.) decaying matter, and is not often passed by people, but there is one record. Horse manure, cow manure, and warm, decaying vegetation, like old straw and grass heaps, are common breeding places. Fig. 24.—Larva of Stomoxys calcitrans: enlarged sketch of right stigmal plate. These plates are one and one-half times their breadth apart. (Greene.) Muscina stabulans Fallen Head of larva (fig. 25) divided into two parts from above, no dis- tinct papilla; two great hooks close together; anterior spiracles with about six lobes (fig. 25b). The surface of the segments is mostly smooth. Beginning with the fifth segment, on the under side, there is a basal, transverse, swollen area, furnished on the crest with rows of teeth; each of these areas is divided on the median line. On the next to the last segment there is a similar area at the tip, but not divided. The seg- ments below also show a transverse line before the middle. The last segment has the anal basal area with spines, but not very prominent, and bears a median and three lateral tubercles with spines. The tubercles COMMON FLIES AND HOW TO TELL THEM APART 147 are nearly in a transverse row. The rounded tip of the body (fig. 25c) shows, across the middle, faint traces of four low cones. The stigmal plates (fig. 26) are scarcely elevated, black, less than their own diameter apart, and each with three very short slits pomting towards those of the opposite plate. This larva is common in decaying vegetable matter; and has been reared from rotten apples, pears, squash, mushrooms and dead insect [ LB £ Fic. 25.—Larva of Muscina stabulans: a, Side view of head and prothorax; 6b, an- terior or thoracic spiracles; c, side view of terminal segments of abdomen. (Greene. ) larve. In one case a considerable number were passed by a child suf- fering with summer complaint. Laboulbéne records larve of this species voinited by a person suffering from bronchitis. Fic. 26.—Larva of Muscina stabulans: enlarged sketch of right stigmal plate. These plates are less than their breadth apart. (Greene.) Calliphora erythrocephala Meigen ‘The head of this larva is distinctly divided into two parts from above (fig. 27, side view of head) ; each part or lobe has a tiny papilla. There are two well separated mouth hooks. The anterior spiracles have from nine to twelve lobes. Beginning with the third, each segment shows an apical swollen ring or girdle, whose surface is scabrous (roughened like a file); these rings are broader below than above, and are here notched on the posterior middle. Each ventral segment, beginning with the fifth, is divided by a transverse groove near the middle. The anal area shows a smooth median process, divided in the middle, and at each outer corner is a cone. The stigmal field is rather concave, the upper lip with three small tubercles on each side, the lower lip with two larger tubercles on each side, and a median pair smaller and lower down. The stigmal plates are about once and a fourth their diameter apart, each with three 148 SANITARY ENTOMOLOGY simple straight slits directed slightly downward but mostly toward those of the opposite plate; the button is distinct (fig. 28). The blow-fly deposits eggs on dead animals, and also on fresh and cooked meats. As such are often accessible to them in pantries, it is readily seen that many larve are swallowed by people each year; there are, however, comparatively few records published, probably because the polluted food causes no trouble. Calliphora vomitoria Linnaeus This larva appears to be identical with that of Calliphora erythroceph- ala. There seem to be no visible characters to separate it from this latter species (figs. 27 and 28). The habits are about the same. Fic. 27.—Larva of Calliphora erythrocephala: side view of heed and prothorax. (Greene. ) Lucilia sericata Meigen Body rather stout, not slender in front. The head is distinctly divided into two parts or lobes, with distinct papilla(figs. 31a, b). The => summarizes the results of these investigations. Those formulae most in use all contain crude petroleum oil and usually soap. A good stock emulsion recommended by Graybill is made of: Hard soap, 1 pound, Soft water, 1 gallon, Beaumont crude petroleum, 4 gallons, Dilute to 1 part emulsion to 3 parts water. Bishopp’s fly repellent consists of: Fish oil, 1 gallon, Oil of tar, 2 ounces, Oil of pennyroyal, 2 ounces, Kerosene, 14 pint. For dairy cattle, Jensen makes a stock solution of crude petroleum with the addition of 4 ounces powdered napthalin, and applies with a brush once or twice a week. Jensen has also given three formule of repellents for protecting wounds from flies. Formula No. 1: Oil of tar, 8 ounces, Cotton seed oil to make $2 ounces, Formula No. 2: Powdered napthalin, 2 ounces, Hydrous wool fat, 14 ounces, Mix into an ointment. Formula No. 3: Coal tar, 12 ounces, Carbon disulphid, 4 ounces, Mix; keep in a well stoppered bottle and apply with a brush. It is of the utmost importance that flies be kept at a minimum in army camps. We can do no better than cite a few authorities of the various armies in support of this. Ainsworth considers the presence of the house fly the greatest danger signal to an army in the field. Savas has called *Repellents for Protecting Animals from the Attacks of Flies, U. S. Dept. Agr. Bul. 131. 166 SANITARY ENTOMOLOGY attention to the connection of flies with the great cholera outbreak in the Greek army. At Gallipoli the flies were in amazing numbers, the food was black with them as soon as it was set on the table. They filled the tents and shelters, settled on the refuse of the camp, and on the unburied dead, and by their annoyance multiplied the sufferings of the wounded and spoiled the tempers of the hale. The flies have been very bad in France. Kirschner states that in the hospitals near the front the enormous number of flies presented a serious danger. Maxwell-Lefroy says that in Mesopo- tamia the tents and trenches were full of flies. ‘The troops at Salonika suffered greatly from diarrhea and dysentery which coincided in appear- ance with the abundance of flies. Wenyon and O’Connor found flies in Egypt largely responsible for outbreaks of amoebic dysentery among the troops. In this connection Dr. Ballou’s lecture on flies and lice in Egypt (Chapter XXXII) will give an excellent first-hand view of conditions in that country. CHAPTER XI Control of Flies in Barn Yards, Pig Pens and Chicken Yards + F, C. Bishopp The question of the control of flies in their various breeding media or places of breeding can not be well divided in the discussion. Attention has been given in a previous lecture (Chapter X) to the general aspects of house fly control and the most favorable breeding media and methods of handling them have been discussed in a general way. Therefore I shall take up the special problems under the three situations listed in the title. Adequate care of the manure and other refuse in these situations will not only result in the prevention of breeding of house flies in them but will also reduce the number of certain other flies which play a part in disease dissemination among man and animals, notably the horn fly, stable fly, Muscina spp., Fannia spp., certain Sarcophagids and lesser‘ numbers of Muscidae known as blow flies, which occasionally breed in hog manure and freely in unconsumed animal matter in garbage. REPRESSION OF FLIES IN BARN YARD The discussion of this problem is bound up closely with that of the control of the house fly through the care of horse manure, etc. If manure is promptly disposed. of as removed from the barn the yards are kept in better condition and the scattered droppings either of horses or cattle are less dangerous as regards fly’*breeding. In drier regions of the country these droppings may be practically neglected. Where large numbers of horses are kept in sheds or yards, the entire area requires treatment. The manure should be scraped up at least as frequently as three-day intervals and scattered thinly on fields or composted and treated with borax or other larvicides. In large stock concentrating points where stockyards and mule sales stables are of great extent the problem of disposing of the manure from the yards is a difficult one. In the Eastern States it has been the usual practice to contract the manure to certain companies or to permit farmers and truckers to enter the yards and get manure when they desire it. One 1This lecture was read September 9 and distributed September 11, 1918, and is now reproduced practically in its original form. 167 168 SANITARY ENTOMOLOGY difficulty has been that stock are often kept in a single pen for feeding for some time and during this time it has been the rule not to clean up the pen. The provision of ample room so that stock may be removed from one pen to another to permit cleaning is important. This also applies to horse and mule sales stables. The restrictions placed on the horse and mule dealers who handle stock fer the army have tended to greatly improve fly breeding conditions in these stables and yards. I have frequently observed these sales stables to be filled with tightly packed manure from eighteen inches to three feet deep. In the case of an East St. Louis mule sales stable where one company has thirty-five acres under cover, the removal of all this manure was an enormous task. Yet it was accom- plished so that the company might continue handling stock for govern- ment use. The manure was hauled several miles to a fertilizer plant where the well decayed part was. piled and subsequently dried, ground and sold as sheep manure for lawn dressings, while the parts with considerable straw were thrown from cars onto rail incinerators and burned, the ash being used in fertilizer mixtures. The entire barns and fences were then gone over with a sand blast machine which cleaned them of all accumula- tion of dust and saliva which had in some cases become quite thick and highly glazed. An effort is being made by the authorities in charge to have the manure from these stables throughout the country moved at weekly intervals. The drying of manure and its sale in powdered condition for lawn dressings, etc., has attained rather large proportions as a commercial enterprise in some of the large cities. This is a satisfactory means of disposal of manure and there are good reasons why the practise should be extended. It appears that where shavings are used for bedding less trouble arises from fly breeding than where straw is utilized. This would undoubtedly favor reduction in the breeding of Stomoxys also. Returning to the question of handling manure in cow lots and small barn lots, it is advisable when labor is at hand, especially in dairy yards, to ick up the droppings daily or even twice a day. This is greatly facilitated by having the yard where cattle congregate in greatest num- bers concreted. In large dairy lots it has been found feasible to bring the manure together by means of an iron road drag (see plate VII). This leaves the manure in windrows so it can be easily shoveled into a wagon. For the disposal of manure from dairies and even on the farm no method is better than the use of a manure spreader (see plate VI) and the scattering of the material thinly on open fields. Of course in cases where all land is cropped it is not convenient to employ this method during certain parts of the year, although it is usually possible to have one portion of the farm available for manuring at all times. CONTROL OF FLIES IN BARN YARDS AND PIG PENS 169 The use of manure pits and boxes has been mentioned in a previous lecture, as has also the Hutchison maggot trap. It appears to the writer that any attempt to construct pits or boxes which are so tight as to prevent the escape of newly emerged flies is likely to meet with failure. In practically all instances the manure is infested more or less when placed in the box or pit, and following this suggestion the writer has been advocating the placing of the manure in boxes and pits which will not allow flies to gain entrance from the outside and which are provided with a cone or tent trap to capture the flies which breed out (see plate V). In the absence of the trap feature these would almost surely escape to the light from the most tightly constructed box or pit which it is feasible to build and maintain. A manure box of this type has been tried by the Dallas laboratory and found to work admir- ably. The number of flies caught is often surprisingly large. For small pastures and meadows it is sometimés feasible to utilize a brush drag to break up the cow droppings. This serves three purposes— preventing the breeding of the horn fly, scattering the manure evenly over the ground, and permitting the grass to grow where it would other- wise be prevented by the piles. While the house fly does not breed readily in pure cow manure the writer has -reared the species from this substance and has also found that where cow manure is mixed with a certain. amount of straw it is a fairly good breeding medium for this species. The horn fly, Lyperosia trritans (Haematobia) Linnaeus, breeds exclusively in cow droppings either in large piles or individual droppings. Blow flies are not known to breed in cow manure, but a number of species of Sarcophagids, most of which, however, do not have scavenger habits, breed in considerable num- bers. The brilliant green fly, Pseudopyrellia cornicina Fabricius (plate III, fig. 4), is very commonly seen on fresh cow droppings; in fact this is usually the most abundant species in this situation in the country. It may be readily mistaken for Lucilia when not examined carefully. This species is of no importance as a human disease carrier as it does not enter houses or visit food.” In preventing flies breeding in yards it is very essential that water troughs be kept from running over and whenever overflows or leaks do occur they should be fixed promptly and the moistened manure and earth cleaned up and hauled away immediately. Special attention should be given to accumulations of horse manure in yards along feeding racks. Here the mixture of horse manure, waste hay and urine forms a satisfac- tory mixture for fly production, 2 Unquestionably its larvae must have an important réle as regards organisms taken up from the manure and passed through their bodies, but whether this rdle is to destroy the organisms or to propagate and distribute is yet to be learned.—W. D. Pierce. 170 SANITARY ENTOMOLOGY The use of larvicides and other chemical compounds in barn yards is usually inadvisable. Thorough cleaning ordinarily will handle the situa- tion. Crude oil has been used in yards where considerable numbers of horses are kept to permit firm packing of the ground and keep down dust in dry weather. Borax, either dry or in solution, may be used in breeding places which can not be cleaned thoroughly. Poultry and hogs consume large numbers of larve and pupe and scatter the manure so it will dry out rapidly. These agencies should not be depended upon, how- ever, to effect control. The employment of conical fly traps about stables and dairy barns, if they are kept properly baited, will aid in reducing the number of house flies. Cheap molasses and water (1 to 3), or milk curd, brown sugar and water in equal parts form good baits. The latter, if kept moist, will remain attractive for two or three weeks. It is comparatively unattrac- tive for the first few days. Hodge type window traps aid in reducing the house fly and stable fly troubles within barns if the barns are closely built and the other windows darkened or screened. FLY CONTROL IN PIG LOTS AND PENS The hog has been looked upon from time immemorial as a filthy ani- mal and he is usually compelled to live in surroundings which would never be tolerated for any other beast. One of the special problems which confronts the municipal and the army sanitarian is the utilization on a Jarge scale of city and camp garbage by hog feeders. There appears to be no more economical way of disposing of garbage than by this method, but the conditions under which the feeding is to be done must be given strict attention by sani- tarians. In the vicinity of nearly every city and large army camp is located one or more of these garbage feeding plants, the number of hogs ranging from a few hundred to several thousand. For the most part the garbage is sold to feeders under annual contract. Army garbage at least is supposed to be free from glass, cans, coffee grounds, and liquids. The contractors furnish the garbage cans, remove the garbage daily and return empty cans which are supposed to be thoroughly cleaned. If the orange, grapefruit, and lemon peels could be eliminated from the garbage, the mass of material not eaten by the hogs would be materially reduced. Garbage feeding plants should be operated under approximately the following set of rules: 1. Location of Feeding Stations.—Station should be located as far from habitations as possible and also well removed, two miles or more, from the city limits or the precincts of an army camp. Our recent experiments show that flies of various species, including the house fly, travel thirteen CONTROL OF FLIES IN BARN YARDS AND PIG PENS 171 miles or more under rural conditions, but that there is a rapid decline in the number of flies which reach points two miles or more from the source of production. It is also desirable that the pens be located a considerable distance from main highways, as passing vehicles help to disseminate the flies. 2. Draimage—Adequate drainage is essential. It is preferable to have hog-feeding stations located on hilly ground and never on flat areas. 3. Adequate Room.—In feeding garbage it is essential in order to maintain sanitary conditions that the hogs be given a considerable acreage. I would place this at a minimum of 225 sq. ft. per hog, or approximately 190 hogs to the acre. Of course as a general principle in fattening hogs it is considered necessary to reduce activity by close penning. It has been proven, however, that hogs make satisfactory gain when heavily fed if kept in large pastures. | iN ENO VIEW Ri A OPEN HOG-FEEDING TROUGH ‘fon: Raps - (er Ararr i i ni : pebbles IK oe en | soi : [8 5" — 10-9" 2 * Scaee to" Fie. 36.—Plans of open hog-feeding trough. (Bishopp.) 4, Feeding Troughs and Platforms.—Concrete feeding troughs and platforms are essential under present inadequate labor conditions. A number of forms of troughs and platforms may prove satisfactory from a sanitary standpoint. In some cases feeding floors are used without any troughs but this necessitates daily cleaning. Under outdoor conditions such as exist in the South, it is advisable to locate the feeding troughs on land with pronounced slope. A simple form of construction consists of a concrete platform about 15 feet wide, length in proportion to number of “hogs (fig. 86). This should have a backward slope of about 10 inches. The trough can be formed by setting a plank on edge in the concrete about three feet from the upper side and parallel with it or by a concrete ridge several inches high to form the lower edge of the trough. The upper edge of the platform should be raised so as to prevent water from washing into the trough and the feed racks to receive the garbage should be constructed over the front edge of the trough in such a way as to 172 SANITARY ENTOMOLOGY receive all drip. The lower side should be provided with a concrete ridge projecting about five inches. This edge along the back will hold most of the unconsumed garbage, bones, etc., as they are worked backward, and facilitates thorough cleaning which should be done at not to exceed three- day intervals. 5. Shade.—lIf location with plenty of trees can be chosen, this is preferable to sheds for protection from the sun. Where sheds are needed for protection either from sun or rain, they should be built on well drained land and never placed over the feeding troughs. They should be seven feet above the ground so as to permit of easy cleaning. Temporary shade can be constructed extending a few feet over the troughs if desired. 6. Contracts—Annual or longer contracts with the Army or with municipalities are far more desirable than monthly contracts as they en- able the contractor to put up proper feeding facilities which he would not do under short contracts. Contracts should specify the character of feed- ing arrangements and penalize failure to keep the premises in satisfactory sanitary condition. The pens should be given frequent inspection by sanitary officers. 7. Cleaning of Yards.—In addition to the cleaning of the uncon- sumed garbage from feeding platform the manure should be scraped up and disposed of, especially during rainy weather. During hot dry weather where ample pasturage is used manure is the source of very little fly trouble. : 8. Disposal of Bones.—Bones which are not retained on the feeding platform and those which are mixed with uneaten garbage should be collected at four-day intervals and placed in fly-proof bone racks. These can be built of lumber and screened on the outside and provided with fiy-proof cover. It is desirable that the bones be removed entirely from the premises at frequent intervals. 9. Avoidance of Transporting Flies on Vehicles—If garbage cans are properly cleaned there is less tendency for flies to follow them than if left dirty. Washing in a moderately weak solution of cresol tends to repel flies from them. The trucks should be washed off occasionally. There is less danger of flies following trucks back to camps when they are provided with covers. 10. Quantity Fed.—Feeding so much garbage to hogs that it will not be cleaned up should be discouraged. 11. Final Disposal of Hog Manure and Unconsumed Garbage.—This material may be scattered thinly over cultivated ground and exposed to the sun or promptly plowed under. Where material is found to be heavily infested with maggots, it is advisable to dump it in piles some dis- tance from the feeding plant and treat it with borax solution. About one pound of borax should be used to each 8 bushels. If the mass is very wet CONTROL OF FLIES IN BARN YARDS AND PIG PENS 173 the borax may be applied dry, but if the material will absorb liquid the borax should be dissolved in water at the rate of one pound to five gallons and sprinkled over it. 12. Dead Hogs.—Dead hogs should be promptly disposed of either by burning on the ground or by hauling to rendering plants. 13. Treatment of Hog Pens Where Flies Are Breeding.—All manure should be scraped up thoroughly, holes cleaned out and the ground sprinkled with borax solution made as above. The holes should then be filled and packed ; crude oil will assist in this. Lime has little value in destroying fly maggots but will tend to dry up moist areas and reduce odor. Ringing the hogs’ noses reduces the number of holes formed and is said to help keep them quiet in fattening. Fly Traps.—Each hog-feeding establishment should be provided with a number of well constructed fly traps, preferably of the conical type, and kept well baited. Black strap molasses and water at the rate of 1 part molasses to three parts water may be used as bait, or 1 part dark brown sugar to 1 part vinegar and $ parts water may be used. The traps should be set in situations where flies tend to congregate and away from danger of being disturbed. Hogs should not be tolerated in towns or cities. On farms the same general rules for elimination of fly troubles should be followed as applied to garbage-feeding stations. For brood sows, good, dry, clean housing is essential from both the fly control standpoint and that of successful breeding. PREVENTION OF FLY BREEDING IN CHICKEN HOUSFS AND YARDS Comparatively little attention has been given to control of flies in poultry houses and yards. This source of fly breeding is one which should not be ignored as it is present even in far more premises than are manure piles from horses and cattle. Several species of flies breed in chicken manure, but the house fly, stable fly and lesser house fly seem to pre- dominate. The writer has found many cases in the South in which these species seemed to be passing the winter in chicken manure. This ap- pears to be a favorable place for the larve to pass the winter as little heat is generated to hasten transformation and sufficient protection is afforded to prevent the destruction of the immature stages by cold. With small flocks of poultry in the back yard the prevention of fly breeding is not difficult but is very likely to be neglected. We have found that flies will breed in rather small accumulations of chicken manure on dropping boards but are produced in greatest numbers if the accumula- tions are on the soil itself. The weekly cleaning of all excrement from the dropping boards and floor is sufficient to prevent fly breeding. Usually 174 SANITARY ENTOMOLOGY it requires more than a few days’ droppings to produce a very favorable breeding situation. The cleaning of houses is of course facilitated by having the dropping boards readily removable or the roosts hinged so as to give free access to the boards. In the South, dropping boards are not being advocated and very few places are provided with them. In such houses a concrete floor is very desirable to make cleaning easy, but seldom found. Sprinkling the dropping boards or floors with air-slaked lime or dry sand helps to take up the moisture from the manure and reduce the attraction for flies. In small places where gardens are available chicken manure can be used to advantage as fertilizer. Where it cannot be disposed of in this way promptly it should be placed in a box under cover from rain and treated with borax as previously recommended. Dead fowls breed many dangerous species of flies and they should be disposed of promptly either by a scavenger wagon in a city, or by burning in rural districts. The care of yards and houses on large poultry farms should be handled in practically the same way as the small one just discussed. There is usually less trouble, however, from these large plants as they receive more constant attention than the small ones. Pigeonries are also a source of some fly breeding as the pigeon coops usually are placed in an inaccessible place and become very filthy. The houses should be made readily accessible and cleaned occasionally. Pigeons should be kept under control, and porcelain dishes provided for nests will facilitate cleaning. The frequent and thorough cleaning up of the manure from all domes- tic animals and fowls tend to reduce the troubles among them from intes- tinal parasites. Spraying with standard disinfecting solutions has the effect of reducing the attractiveness for flies, of excrement, soiled floors, etc., in addition to the germicidal action. Cleanliness and spraying of premises also increase the efficiency of fly traps. CHAPTER XII Myiasis—Types of Injury and Life History, and Habits of Species Concerned? F. C. Bishopp Myiasis is a term applied to’the attack of living man or animals by fly larve. The medical profession usually assigns specific names to the infestations according to their location—as dermal (in or under the skin), nasal (nose infestation), auricular or otomyiasis (ear attack), intestinal, etc. These names are not entirely satisfactory as often one form will develop into another or one species of larvae may be concerned in attacks in many different regions. And again several species may attack the same region but produce different types of injury, or the point of attack may vary with the stage of the larve. Any attempt to classify the different types of myiasis according to character or place of attack or species of fly concerned seems to have its objections and difficulties. For convenience in discussion an attempt is made to divide the subject from the standpoint of method of attack into the following groups: First, TISSUE-DESTROYING FORMS, including those species which are ravenous feeders and destroy living tissues. For example the screw-worm, Chrysomya macellaria Linnaeus. The species which are included in this group with the exception of Wohlfahrtia magnifica Schiner attack living animals secondarily, the main source of breeding being in dead animal matter. Second, SUBDERMAL MIGRATORY FORMS which are parasitic in animals or man and occur during the major part of their lives beneath the skin. For example, the ox warble, Dermatobia or “torcel,” in man, etc. Third, LARV INFESTING THE INTESTINAL OR UROGENI- TAL TRACTS. These usually feed to a lesser or greater degree on food or excrementitious matter within the body. For example the larve of the latrine flies of the genus Fannia and of certain flesh flies of the family Sarcophagidae. Infestations largely accidental, except horse bots and related species in animals which are truly parasitic. Fourth, FORMS INFESTING HEAD PASSAGES. ‘True parasites 1This lecture was presented November 18 and distributed December 20, 1918. 175 176 SANITARY ENTOMOLOGY of animals or man occurring in the head sinuses, throat, or occasionally the eye. For example, the sheep bot, Oestrus ovis Linnaeus, and the deer bots, Cephenomyia spp. Fifth, BLOOD-SUCKING SPECIES. Highly specialized forms with blood sucking as a normal habit, exclusively parasites of man or animals, such as the Congo floor maggot attacking man, and larve of the genus Protocalliphora attacking birds. Myiasis is caused by many species in several families. The habits, in regard to myiasis, of the species of any single family vary widely as might be expected in groups which have become more or less specialized. For instance, the family Oestridae, which is the only family having all its species concerned, in myiasis, has members which infest the stomach, others which develop in the nasal passages and still others which produce cutaneous myiasis. The family Muscidae also exhibits very diverse habits in this regard, some members being concerned in destructive myiasis, others in specialized dermal cases and still others are blood suckers. Myiasis in animals is not generally considered in connection with human cases. There exists, however, a very intimate interrelationship ; in fact, the prevention of myiasis in man is largely dependent upon the control of the trouble in animals. Entomologists engaged in sanitary work must be prepared to handle insect attack on animals as well as on man. Owing to the need for careful determination of the exact species con- cerned in cases of myiasis, both for the immediate needs of the case and for the benefit of science, it is highly desirable that the larvae concerned be bred to adults whenever possible. Specific determination of the larve, especially when small, is, to say the least, very difficult, but a few should be preserved in alcohol for record and future identification when larval characters are better understood. Some suggestions as to breeding methods are apropos. There is no use endeavoring to rear Oestrids after extraction unless well matured. Most of the larve from wounds will usually develop on beef. Care must be exercised in rearing the flies to avoid infestation of the material by other species, especially Sarcophagids which will drop larve through screen wire onto meat or excrement. A double cage is best to avoid this; one of these should have a solid top. Good ventilation is important and sand slightly moist but not wet should be provided beneath the meat. The meat may be partially buried to retain moisture and reduce odor. It should be remembered that the larve have a strong tendency to migrate when ready to pupate. TISSUE-DESTROYING FORMS It should be said that most forms of larve attacking man or animals may destroy body cells to some extent but not in the sense of the rapid MYIASIS—TYPES OF INJURY, LIFE HISTORY, HABITS | 177 tearing away of tissues, as exhibited by species in this group. This is the most dangerous type of myiasis in man and one of the most important sources of loss due to insects among domestic animals. As previously pointed out, practically all the flies included in this group attack living animals as a secondary method of reproduction. It should be stated most emphatically that cases of myiasis, either in man or animals due to species in this group, are more or less intimately associated with violations of the best sanitary principles. The vast majority of cases of this type of myiasis occur in the warmer parts Prate IX.—Carcass partly destroyed by larvae of the American screw-worm fly, Chrysomya macellaria. (Bishopp.) of the world. In the United States, as is well known, our principal source of trouble is due to the Muscoid fly, Chrysomya macellaria Linnaeus, commonly spoken of as the screw-worm (sce plate I, fig. 3; plate II; plate IX). Several other species are concerned to a greater or less degree, among these should be mentioned the black blow fly, Phormia regina Meigen (plate I, fig. 4), the green bottle flies, Lucilia casar Linnaeus (plate I, fig. 2) and L. sericata Meigen, certain of the flesh flies (Sarcoph- aga spp. (plate III, fig. 1) and occasionally some of the hairy blow- flies of the genera Cynomyia and Cailiphora. Fortunately from the standpoint of the sanitary entomologist, the methods of control are in general very much the same for all species of this group, owing to the similar habits and not vastly different life his- 178 SANITARY ENTOMOLOGY tories. All of the species, except Wohlfahrtia magnifica Schiner, are carrion breeders although the adult flies are attracted to various kinds of food, especially those with strong pungent odors as come from the cooking of cabbage or turnips. A few develop occasionally in human excrement; normally, however, the decomposition of animal matter has the strongest attraction for them and in many regions it is with great difficulty that animals can be slaughtered without having the meat contaminated by their presence in large numbers (see plate II). Garbage containing meat and bone will attract and breed them. America.—The screw-worm fly occurs throughout the United States, but is of little importance as a pest except in the Southwest where in some sections it is a veritable scourge to the raisers of livestock. The life history of this species will serve as an illustration for this group of flies in the United States. The eggs are deposited on carrion, especially on animals which have died recently. These hatch in a few hours into maggots which enter the tissues rapidly and become mature in about six to twenty days. In living animals development seems to be rather more rapid. Pupation takes place in the soil from the surface to three or four inches deep and the flies emerge in from three to fourteen days. The total development period from attack to adult has been found to vary from seven to thirty-nine days. The activity of this species is confined to the warmer part of the year, usually from about April first to November first in the Southern States. The black blow fly, Phormia regina, on the other hand, appears more resistant to cool weather and becomes most numerous in the southern region during early spring and late fall. This is also true to a large extent with the large hairy blow- flies. These latter entirely disappear during the summer months in the southern latitudes. Infestations of screw-worms in animals occur on any portion of the body where there is broken skin or even on sound skin where blood spots occur. For the most part, however, the infestations follow mechanical injury or where ticks have been crushed on the host. In man practi- cally any part of the body may be attacked, but the most common type of myiasis is nasal. This is especially true in Central and South America. Such infestations are usually associated with malignant catarrh or bleeding from the nose, and practically always with careless modes of living. The larve enter the nose and penetrate the tissue, rapidly producing extensive cellulitis and usually accompanied by con- siderable serous or bloody discharge. If not detected for two days the injury is likely to be very serious. The frontal and ethmoid sinuses may be entered and the cartilage and even the bone attacked. Often the tissues of the nose and beneath the eyes begin to collapse and sometimes excavation reaches to the surface, giving permanent disfiguration. This MYIASIS—TYPES OF INJURY, LIFE HISTORY, HABITS 179 extensive destruction of tissues often results in septicaemia or meningitis. Infestation of wounds on the battlefield or even in hospitals is not at all infrequent, but such cases are much more easily treated than nasal infes- tations, ; The black blow fly, Phormia regina Meigen, usually infests only old suppurating wounds. In livestock it is commonly found following dehorn- ing and has also been proved to be a common source of wool infestation of sheep in the Southwest. In the latter case the soiled wool following lambing attracts flies and the maggots feed on this for some time but later may enter the sheep itself and cause its destruction. The green bottle flies, Lucilia sericata Meigen and L. cesar Linnaeus, which are commonly known as the wool maggots in the British Isles, occur throughout the United States. They have been known to infest wounds in man and animals but the main source of trouble has been the infestation of soiled wool on sheep. The method of attack in wounds is similar to that of screw-worms, but the tissue destruction is less rapid although this depends largely in either case upon the number of larve present. They are more abundant in towns than in open country. In South and Central America and the West Indies, Chrysomya macellaria abounds and gives similar troubles to those in the United States. In Brazil, Sarcophaga lambens Wiedemann and S. pyophila N. & F. have been reported by Neiva and De Faria to infest wounds. In Hawaii Calliphora dux (Thompson) has caused considerable loss by attacking soiled wool and scabs on sheep. Evrore.—In Europe the principal trouble from myiasis occurs in southern Russia. A considerable number of cases occur in the Mediter- ranean region and some farther north in Australia and Germany. In southeastern Russia, according to Portchinsky, the vast majority of cases of this type are caused by the flesh fly, Wohlfahrtia magnifica Schiner, which appears to have habits of attack on man and animals very similar to that of the screw-worm fly in America. He speaks of its attack usually following wounds on the bodies of cattle, horses, pigs, dogs, and poultry. It also commonly infests the feet of animals suffering from foot-and- mouth disease. The cases in man occur most commonly in the nose, ears, and eyes. The injury is often serious, resulting in deafness, blindness, or facial disfiguration, and not infrequently in death. This fly deposits living larve, and infestations in man are usually the result of sleeping outdoors during the warm part of the day. The fly is most abundant in fields and woods rather than in towns. It is said to breed in living animals only, thus differing in an important respect from the screw- worm fly. While this species is not commonly spoken of as a pest in western Europe, Liitje reports considerable trouble from it in the western war 180 SANITARY ENTOMOLOGY theater, especially during 1915. It infested wounds and interfered with their proper treatment and also was responsible for many infestations of the genitalia of cows in that region. Next in importance comes the flesh fly, Sarcophaga carnaria Linnaeus. This form does not seem so prone to attack living animals as Wohlfahrtia magnifica Schiner, but there are numerous cases of myiasis in old sup- purating sores. These may occur in any part of animals or man. In the Petrograd district Lucilia caesar Linnaeus is responsible for some cases of myiasis, while in Denmark, Holland, and parts of Germany and France, L. sericata Meigen is concerned in the infestation of wounds. Calliphora erythrocephala Meigen, Musca domestica Linnaeus and Muscina stabu- lans Fallén (plate ITI, fig. 2) are said to oviposit on corpses on the battle- field soon after death but before putrefaction sets in. The larve of Anthomyia pluvialis Linnaeus has been reported as being concerned in auricular myiasis. Probably this species should be con- sidered as a feeder on excreta rather than placed with tissue-destroyving forms. Arrica.—Wohlfahrtia magnifica Schiner is reported by Gough in Egypt as being taken from ulcers behind the ears and from orbits of patients in the ophthalmic hospitals. In tropical Africa Lucilia argyro- cephala Wiedemann commonly attacks mammals, man, and birds. Mem- bers of the genus Pycnosoma, which has been included with Chrysomya by some authors, cause myiasis in numerous caases. Pycnosoma megaceph- ala and P. bezziana Vill. are frequently mentioned in literature in con- nection with cases of myiasis in cattle, horses, camels, and other animals, as well as man. P. putoriwm Wiedemann, P. marginale Wiedemann and Chrysomya chloropyga (Wiedemann) Townsend are also concerned. Sarcophagids have been recorded as infesting wounds; S, haemorrhoidalis Fuller and S. regularis Wiedemann being mentioned in particular. Asta.—While there are numerous references to myiasis cases in Asia, our knowledge of the species concerned is limited. Members of the genus Pycnosoma, particularly P. flaviceps Walker, are concerned with cases in India. This species and Lucilia serenissima Fabricius have been men- tioned particularly as being troublesome by attacking cattle after out- breaks of foot-and-mouth disease. It is possible that they may be con- cerned with the spread of this disease in addition to the injury wrought hy their burrowing into the tissues. The cosmopolitan Lucilia cesar Linnaeus is responsible for some cases of myiasis. Several Sarcophagidae have been reported as causing nasal myiasis of man in parts of India, but most of these have not been specifically determined. S. ruficornis Fabricius seems to be among those most frequently concerned. Avstratisa.—While reports of destructive myiasis in man are com- paratively few from Australia, certain parts are subjected to veritable MYTASIS—TYPES OF INJURY, LIFE HISTORY, HABITS 181 plague of myiasis among sheep. The center of the region where this scourge occurs is in New South Wales, where work for the commonwealth government has been carried on by Professor W. W. Froggatt for several years. Only a brief mention of the species concerned and the character of attack can be given. The loss is brought about through the blowing of the soiled wool, particularly around the vents of the ewes. The infestation, if not promptly treated, spreads forward in the wool, resulting in a large loss in the clip and often the larve gain entrance to the bodits of sheep and cause their death. Even though penetration does not occur, the skin is acutely inflamed and gives rise to fever, loss of appetite, and sometimes death. Froggatt states that he has bred 1,050 flies from the maggots in one pound of wool. Froggatt holds that the blowing of wool is largely an acquired habit on the part of Australian flies, as practically no cases of this kind were noted up to 1903 or 1904. He attributes the acquisition of this habit to the extended drought which destroyed large numbers of animals of all kinds and resulted in the production of myriads of flies. He thinks that during this period several species of flies acquired the habit of depositing in “smelly” wool. He also considers the more extensive breeding of heavy wooled sheep to be a contributory factor. It is certain that injury from blow-flies has developed from an almost unnoticed trouble to a problem of first magnitude within the space of a few years. During the first few years of the acute trouble the small yellow house fly, Anastellorhina | augur Linneus, and the golden hair blow-fly, Neopollenia stygia (Fabricius) Townsend (Pollenia villosa Robineau-Desvoidy) appeared to be the principal culprits. In 1913, when the work was taken up more extensively it was found that the “green and blue” sheep maggot fly, Chrysomya rufifacies Macquart (Pycnosoma), was assuming first impor- tance in connection with the infestation of sheep. The difference in apparent injuriousness is probably governed largely by the seasonal conditions as in the case of species in our own country, C. rufifacies appar- ently being concerned largely with cases of myiasis in summer and A? augur during the cool weather. The life histories of these flies do not differ materially from that of the screw-worm fly, the life cycle being completed in about two weeks under favorable conditions. Other species which have been bred from wool in Australia are Microcalliphora varipes (Macquart) Townsend, the Anthomyid, Ophyra nigra Wiedemann, Sarcophaga aurifrons Macquart, and the cosmopolitan Lucilia sericata and L. cesar, and possibly L. tasmaniensis. 182 SANITARY ENTOMOLOGY SUBDERMAL MIGRATORY SPECIES The species concerned in this form of myiasis are truly parasitic. In the cases of man they can not be considered as especially dangerous, but in animals they assume first rank as destructive parasites. The type of myiasis produced by these larve is described under various names in medical literature but especially mentioned as creeping disease. This is owing to the movement of the larve in the subcutaneous tissues. In the United States we have little concern for cases of myiasis in man produced by this group of flies as they are comparatively infre- quent. The species concerned are Hypoderma, probably mostly lineata DeVillers and Gastrophilus, probably mostly intestinalis DeGeer (plates X, XII). Unfortunately the larve concerned usually have not been preserved, and in a very few cases have any larve from man been reared to maturity. The sanitary entomologist is not particularly concerned with the Oestrids infesting cattle, but on account of their importance to the veterinary entomologist they are here briefly discussed (see plates XI, XIII). There are two species in this country, H. lineata De Villers and H. bovis DeGeer. The former is the predominant form in the United States, especially in the southern three-fourths of the country, while the latter is more restricted to the northern tier of States, New England and Canada. The adults are known as heel flies and oviposit on the hairs, prin- cipally on the legs of cattle. These eggs hatch in three or four days and the larve penetrate the skin at the point of attachment or in some instances may be taken in by licking. After several months spent in the body of the animal they appear during the late fall and winter months under the hide along the back, forming subcutaneous tumors. When full grown these grubs emerge from the host, drop to the ground and after about twenty-five to thirty-five days spent in the pupal stage produce flies which are ready to attack cattle the first warm days during spring. Several cases have recently come under the observation of Mr. E. W. Laake and the writer of the occurrence of this species in the backs of horses. These are responsible for the production of lesions which prac- tically render the use of the infested animals as saddle horses impossible for a few weeks. There are a number of records of the occurrence of the young larve of these flies in man, especially children. Attention is usually first called to them on account of pain, soreness or itching in the region of the shoulders or face. The irritation is sometimes rather acute and its location moves with the burrowing of the larve. Before becoming mature the grubs appear near the surface under the skin or beneath the mucous membranes of the mouth and can there be extracted with ease. MYIASIS—TYPES OF INJURY, LIFE HISTORY, HABITS — 183 Pirate X.—Horse bot flies. Fig. 1 (upper).—Gastrophilus intestinalis, the common bot. Fig. 2 (lower).—Gastrophilus haemorrhoidalis, the nose fly. (Dove.) 184 SAN ARY ENTOMOLOGY Prare XI.—Phases of the life cycle of bot flies. Fig. 1 (upper right)—Empty eggs of the cattle bot, Hypoderma lineata, Fig. 2 (upper left)—Eggs of the common horse bot, Gastrophilus intestinalis. Fig. 3 (center)—Full grown larva of JTy- poderma lineata. Fig. 4 (lower right)—Empty puparium of Iypoderma lineata. Fig. 5 (lower left) —Empty puparium of Gastrophilus intestinalis. (Bishopp.) MYTASIS—TYPES OF INJURY, LIFE HISTORY, HABITS = 185 Prare XII.—Method of attack by the common horse bot, Gastrophilus intestinalis. Fig. 1 (upper).—Eggs on horse’s legs. Fig. 2 (lower).—Larvae attached to walls 1) of stomach, showing lesions caused by removed bots in center. (Bishopp.) 186 SANITARY ENTOMOLOGY Prate XIIJ.—Method of attack by the cattle bot, or heel fly, Hypoderma lineata. Fig. 1 (upper right).—F ly ovipositing on cow’s leg. Fig. 2 (upper left).—Portion of cow’s back showing larvae, empty holes and pus exudate. Fig. 3 (lower).—Heavy- ily infested cow. (Bishopp.) MYIASIS—TYPES OF INJURY, LIFE HISTORY, HABITS 187 These infestations probably come about through the accidental depositions of eggs on the bodies or clothing of man, especially children. The possibility of this method of infestation is emphasized through the experience of Dr. Glaser, who while studying ox warbles in Germany had a fly deposit an egg on his trousers which in due time hatched and the young larva penetrated the skin of his leg. Later its presence in the oesophageal region was detected by an uncomfortable feeling. The larva apparently passed up the oesophagus and later was extracted at the base of one of the molar teeth. In instances where the Oestrid fly of the genus Gastrophilus attacks man the conditions surrounding the infestation as well as the exact identity of the larva are less well understood. It is supposed that the young larve are in some way brought in contact with the mucous mem- Fic. 37.—Full grown larva of the human bot, Dermatobia hominis. (Drawing by Bradford.) Actual length 14.5 mm. branes of the lips, mouth or eyes and penetrate them, later appearing under the skin and moving about in a manner somewhat similar to Hypoderma. The life history of the species of this genus will be dis- cussed under intestinal myiasis. AmeErica.—In America in addition to the Hypodermas we have among the lower mammals dermal myiasis produced by several different species of Oestrids in the genus Cuterebra. These are most commonly met with in rabbits, squirrels and certain field mice. Usually they appear to cause no serious injury except in the case of one form, which is prone to attack the testicles of squirrels and was given the name of Cuterebra emasculator Fitch (equals C. fontinella Clark). In South America a very interesting and more important form of myiasis in man occurs. This is produced by the Oestrid, Dermatobia hominis (Carl Linné, Jr.) (nowialis Goudot, cyaniventris, Macquart) (fig. 37). This form appears to be normally the parasite of cattle, horses, donkeys and certain wild animals. It is reported as being a serious pest 188 SANITARY ENTOMOLOGY of cattle, in some cases causing the death of many calves, especially when the cutaneous tumors become infested with larve of Chrysomya. The life history and habits of the species have not been fully eluci- dated, although a number of important contributions have been made. It is generally concluded that the infestation of man is brought about in the following indirect but very interesting manner: The eggs of the fly are deposited on the bodies of certain bloodsucking insects, especially the mosquito known as Psorophora lutzi Theobald (Janthinosoma), or attached to leaves frequented by these insects whence they adhere to them. The eggs are attached vertically on the under side of the abdomen or the legs. The embryos appear to remain dormant though fully developed within the egg and when the bloodsucking dipteron finds a host, the heat of the animal or the blood taken up stimulates the larve to break from the shell and penetrate the skin of the host. Dermal tumors are formed by the larve, a well-marked hole opening to the outside as in the case of the ox warble. When the grubs become full grown they leave the host, drop to the ground and transform to adults. The period in the host ranges from two to six months. During this time there is more or less inflammation and sometimes acute pain. This form is widely distributed through tropical America. Lieut. L. H. Dunn has recorded cases of apparent transmission of the eggs by ticks. In South America Dr. J. C. Nielson has reported the occurrence of the Anthomyid flies (Mydaea anomala and M. torquens) as producing’subcu- taneous tumors in various birds in parts of Argentina, and Dr. C. H. T. Townsend records M. spermophilae as parasitic on nestlings in Jamaica. Evrope.—Several cases of dermal myiasis have been reported, espe- cially from Russia. These are attributed to infestations of larve of Hypoderma and Gastrophilus. The infestation of reindeer in Lapland and farther south in Norway by larve of the Oestrid fly, Oedemagena tarandi Linnaeus, should be mentioned. The infestations are almost analogous to those in cattle caused by Hypoderma. The eggs are laid on the hair during the spring and later the larve appear in the submucous tissues of the back. As many as 300 have been reported as occurring in a single animal. This same species no doubt infests the reindeer in Alaska and Canada. Arrica.—In Africa the outstanding form of dermal myiasis is pro- duced by the Muscid fly, Cordylobia anthropophaga Griinberg, commonly spoken of as the Tumbu fly (figs. 38, 39). The larve are known as “Ver du Cayor.” These develop in the skin of man and various other hosts including dogs (probably the preferred host), cats, horses, and other domestic and wild animals. The attack is painful but not serious, though no doubt when numerous specimens are present unpleasant symptoms fol- low. The life history of this form has not been entirely elucidated, but MYTASIS—TYPES OF INJURY, LIFE HISTORY, HABITS 189 it is generally believed that the eggs are deposited on the ground in places frequented by hosts and the larve hatch and penetrate directly through the skin. In some cases it appears that eggs have been deposited on clothing, especially if moist with perspiration. They appear in March ASET Fic. 38.—Full-grown larva of the Tumbu-fly (Cordylobia anthropophaga, Grinberg). Ventral view. X 6. (From Austen.) Fic. 39.—The Tumbu-Fly (Cordylobia anthropophaga, Grinberg). Female. X 6. (From Austen.) and diminish until some time in September when they entirely disappear. Experiments conducted by Roubaud indicate that the choice of host depends mainly on body temperature, the high temperature of hogs and fowls being fatal to the larve. Cordylobia rodhaini Gedoelst is the cause of cutaneous myiasis in the 190 SANITARY ENTOMOLOGY forest regions of Africa. Man is an accidental host, the species normally infesting thin skinned wild mammals. According to Rodhain and Bequaert, who have given much attention to the biologies of this and related species, the eggs are deposited on the ground in the burrows fre- quented by the animals, the larve hatch out and penetrate the skin when the hosts are lying upon them. The larve develop within the host in twelve to fifteen days. The pupal stage, which is passed in the ground, ranges from twenty-three to twenty-six days, the life cycle being about forty days. Another Muscid genus, Bengalia (especially B. depressa Walker), causes cutaneous myiasis in man in Rhodesia and other parts of Africa. The eggs are deposited on the clothing or person of man and on the hair of animals. Another interesting form is Neocuterebra squamosa Griinberg, which develops in the adipose tissues in the soles of the feet of the African elephant. INTESTINAL AND UROGENITAL MYIASIS There is every reason to believe that myiasis of the intestinal tract and urogenital openings results largely from careless modes of living. The types of myiasis included in this group should not be confused with urogenital myiasis caused by Chrysomya and related forms.