; ae No. a New SERIES. | S258 ee | ~~ U.S, DEPARTMENT OF AGRICULTURE, | DIVISION OF ENTOMOLOGY. Fi] Some # | AHS. | : 1896 THE PRINCIPAL PeUSKHOLD INSECTS OF THE UNITHD STATES: a BY jay S| mh. OO; HOWARD AND ©. L. MARLATT. Bae : ) WITH A CHAPTER. ON _ Insets AFFECTING DRY | es LE FOODS. BY EF. H. CHITTEN VES, WASHINGTON: GOVERNMENT PRINTING OFFICE, hake Page. /%2IDG BULLETIN No. 4.—NEW SERIES. ea DEPARTMENT OF AGRICULTURE. DIVISION OF ENTOMOLOGY, Ho? THE PRINCIPAL BOUSHHOLD INSECTS OF THE GONE ED STEAS TEs. BY Li O. HOWARD AND C. L. MARLATT. WITH A CHAPTER ON INSECTS AFFECTING DRY VEGETABLE FOODS. BY Fy H. CHITTENDEN. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1896. Nm UF LETTER OF TRANSMITTAL. U.S. DEPARTMENT OF AGRICULTURE, DIVISION OF ENTOMOLOGY, Washington, D. C., July 7, 1896. Sir: I have the honor to submit for publication the accompanying account of the principal household insects of the United States. . Respectfully, L. O. HOWARD, Entomologist. Hon. J. STERLING MORTON, Secretary of Agriculture. 2 Pal = Boe AA > } fa Pe 06 au 4 CONTENTS. AMMEEIRAICICING Cee ee naa eee ee ea a See oom Saw Fae bees sae ae CHAPTER I.—MOSQUITOES AND FLEAS. (By L. O. Howard).-.........-.---.-- APLAR Si CULLUCHELO SPs eae oo os ai = rato eae ns Oa sities eleio ie ieee eos @he cap and doe flea (Pulex serraticeps Gerv.)... .-- <6. <5. 22 snen de eses cise CHAPTER IJ.—THE BEDBUG AND CONE-NOSE. (By C.L. Marlatt).........--- meebo bus (Cimes lectularius Linn.)~ 2/5525 so 2 See tees Soot ssc oS ese ole ’ The blood-sucking cone-nose (Conorhinus sanguisuga Lec.) .---.---------- CHAPTER III.—HOUSE FLIES, CENTIPEDES, AND OTHER INSECTS THAT ARE ANNOYING RATHER THAN DIRECTLY INJURIOUS. (By L. O. Howard and parmniremel ePctrtel cai i0)) sae eee = ce ae 2 oe Wee Gero fen eet ce Boers Se Sallie Pmmcedives (iiscea domestica, enal.). .-(leO.H.) 2. 225.552 ee ace Set eet The house centipede (Scutigera forceps Raf.). (C.L.M.)...-...--.-..----- mae clover mite (bryobia pratensis Garm.). (C.L.M.).-..225-.252.5-2---- The house cricket (Grylius domesticus Linn). (C.L.M.)-....----.-..---.-- mie paper wasp (Vespa germanica Fab.). (C.L. M:).---. 2.222 2.25 22 eee CHAPTER IV.—SPECIES INJURIOUS TO WOOLEN GOODS, CLOTHING, CARPETS, MPHOLSTERY, ETO. (By L. O. Howard and C.L. Marlatt) .-...--.. 2.2.2. The carpet beetle or “buffalo moth” (Anthrenus scrophularie Linn.). ie Ee LED epee gee Ps a a ER TRS aR 2 Sra a a US The black carpet beetle (Atiagenus piceus Ol.). (L.O.H.) ----.---------- ihe clothes moths (Tinea pellionella,; et al.) (C.L.M.) .--.--.5. 2----5--% CHAPTER V.—SPECIES INJURIOUS TO WALL PAPER, BOOKS, TIMBER, ETC. (By eh Ley SLUDGE 0) | Se SE het a a gS a ee Mieammntieramy (LeEnnes flavipes ANOlL, eso a25 52 1542 soe a sows ee ee eee Menten ish (Lepisma saccharina Linn.) 222-3: S422 hl Se es = Fee eee elke fie eel louse (Airopos divinatoria Fab:)22-. 22.22.22 22 see ce ile ese The American spring-tail (Lepidocyrtus americanus Marl.)-.-.-.------------ CHAPTER VI.—COCKROACHES AND HOUSE ANTS. (By C. L. Marlatt) --..-.-- Cockroaches (Periplaneta americana, et al.)....--.------ shrine Piney raced Stems House ants (Monomorium plaraonis, et-al.).--..+.--- s4e6--2+-22< 222-50 5-5- CHAPTER VII.—SOME INSECTS AFFECTING CHEESE, HAMS, FRUIT, AND VINEGAR. Miswallm Oe ONVAL Ces meh ae ie elec oe eats 5 One toe omee AT ai) MC ue Re The cheese, ham, and flour mites ( Tyroglyphus longior and Tyroglyphus siro) - The cheese skipper or ham skipper (Piophila casei Linn) .-...----.------- The red-legged ham beetle (Necrobia rufipes Fab.).-....---.-------------- tredarderbeetle,(Vermestes lardarius Winn.) 2.2222 s222-. 252% sa- 255 ecene hermit hes or vinegar flies Drosophila spp:)-4-.222-2-----s-+<2-.s4--- Cuaprer VIII.—INSECTS AFFECTING CEREALS AND OTHER DRY VEGETABLE HOODS seo yrs de @mitteMmden): 2-2 250.4 oes See eos. bce sees os Pure si Oui CCUles rm ar mya een. sae ORY Pokies a oe Pie mealeworms): 2:2 2..82.. 2.2: pea cdi nee meh pea UE Cae Sei IIs Tech Sin TUNG TUAV SEE SANIT OS csc ie MN ae EE iB eR ee eee TEM, COPE WO TUE] SVS LETS) A Seem le a A Phe Ra hedrmice-store pectle. and its) allies 22255. 92 {ees seco. fee te Species of occasional occurrence in vegetable stores......-....---------- ILLUSTRATIONS. Page eet 0 nlex puncens AdUIt Soo - sais see. Some ales weet wae mee Ce merenne 10 =e alex punsens: eres and youn? larvyx.. 025.52... 5-2 ss. cose 2-5 11 a -Gilex punrens: mead: of larva; sy. sco seo] 6220-5 ss cen ac lace eccen 13 Plex puncens larva and) pllpa 22-52 c..2 soa S22 on St hele 15 fe Palex serraniceps> eco, adult retG. os. so2 s-co-e ea aos eens 25 ne Ox SEITALICONS: IAEVara cscs on aes ose we ee a etc succes Soe cee e 27 OMe x 1OCUUL ALIS. GM Gis. | nis orem cotta sled ters wisps Syne wrnin o inte sie 32 Sciex lectularius: eco and young larva-2 5.52). 222.322. -5 22 2h 33 oF wnmex tectularius: larval stages 2.2. 258-2 jee So eee 35 10.—Conorhinus sanguisuga: pupa and adults ................---.---- 39 11.—Conorhinus sanguisuga: larva and egg.-......-...--..-----.------ 40 12.—Conorhinus sanguisuga: head, showing mouth-parts -...--..----- Al 13.—Musca domestica: adult, puparium, etc ......-..----..----------- 43 14.—Musca domestica: larva ......---- Bree ee Ne niatet ce Sins ioe ot elem 45 ee BE Se a GOmMes tea Uae ooo cso S kane onc Sore @ See ne-n aoe ei inie eisai 46 i Semler tOLCeps = AGULbe = 24. en Sa cene se om ae Mood eos aero ss A8 ae Seni Sera LONce ps: IAEVE a2 2.11 ee ck Seton aac oe eh eee ee 49 18.—Bryobia pratensis: females and details.................---------- 51 SEOs CACMSIS >: lAEVibs oan onc Sosy a sk. Sascha ss cee eases cise selec 52 GEMS AOMeEStICUSs, AUG 2225-2 ae yee eee Silos le chine lence Soe 53 ae Vals ASSIMMUIIS = *ACMIb 2. set ono soo ceee Soc sass cee eee once cee 54 oe ES ASS UMMlIS)s WAN TSi2- 2652 ao eases eo oS. eee se ee eee ers 5d 23.—Anthrenus serophulariz: all stages ----..--------.. +--+. -------- 58 Poe Abbacenus piceus:. all-stagessy..422,--2- ssc satecds cco kel Sele Seed 61 “eines pelionella: adult and larva: .22..c.ste0sci 305... 2st cee 63 26.—Tineola biselliella: adult, larva, and cocoon........--..---.------ 66 i erichophaga tapetzella: adult moth’ .2...--2 9.2.2.2... --22- 5-25 67 Zo lermes wavipes: male and female... 5.222 222. 222. 225. 22222. 52252: 70 29.—Termes flavipes: head of winged female .........--..----.-..---- 72 30.—Termes flavipes: newly hatched larva and egg ...---.------------ 73 ple hermes: tlavipes- difteremt forms: 4) 50555 2224. 2. oo. See se ee oe 74 - oo kepisma saccharina: adulh 2.22 << 22 2c eee ae sabeeess se Js koe eclecee 76 do epismar domestica #/adulb 225,05... 28s 0s once tee oe ieee eee CH Jo AULOPOs Cuvamatoria: adult... 522 [ake sees Sete poco oe ase See 79 35.—Lepidocyrtus americanus: adult, dorsal view ......-----.-------- 82 36.—Lepidocyrtus americanus: adult, ventral view .....-.....-.---.---- 82 37.—Lepidocyrtus americanus: adult, lateral view..............------ 83 Jo. reriplaneba americana: adult.. =... -ssss sosm esse c+ cose cons Coe o Sen 84 39.—Periplaneta americana: egg capsule ...............---.---------- 89 40.—Periplaneta australasiz: adult and pupa................-..--.---- 91 41.—Periplaneta orientalis: different forms -....-.............--.------ 92 42.—-Phyllodromia germanica: various stages ......-...----.---------- 92 43.—Monomorium pharaonis: female and worker...-...----.---------- 96 44.—Monomorium minutum: male, female, and worker..........-..--- 97 ILLUSTRATIONS. Page Fig. 45.—Tetramorium cespitum: different forms -......-.---..----....--. 98 46.—Tyroglyphus longior: male and female. ---- seeactet se ee 100 47.—Tyroglyphus siro: female 22.2 vee. she cae oo cee eee 101 48.—Piophila casei: different forms. 2222-22. 22-0 95--o5-5 22200 103 49.—-Necrobia rufipes: larva and adwlt_.22---2.22.5.-...222-)- eee 105 50.—Dermestes lardarius: larva, pupa, and adult .----..-....--.------ 108 51.—Drosophila ampelophila: different stages ....-.-...-------..----- 110 52.—Tribolium confusum and ferrugineum: different stages..-....---- 113 53.—Echocerus cornutus: adult male. 25-22 2221 5.22 --- 26. 115 54.—Tenebrio molitor: different stages ..-...../..2.<:<- ----22 -seeeeee 116 55.—Tenebrio obscurus: adult male. 225-222. -22--22--o2 + ee ee 118 56.—Plodia interpunctella: different stages.............--..---------- £19 57.—Pyralis farmalis: adult moth, ete... 22... 2.22 -.2. --2-5. 2225 119 58.—Pyralis farinaliscveces, larva, €bC oe ae eee Pes 120 59.—Silvanus surinamensis: larva, pupa, and adult ..............----- 121 60.—Tenebroides mauritanicus: larva, pupa, and adult -....-.-....--- 123 61.—Sitodrepa panicea: larva, pupa, and adult ...........-.-.--.--=_- 124 62.—Sitodrepa paniceai: head of larva: --22522-s5---2 25522 -eee 125 63.—Lasioderma serricorne: larva, pupa, and adult -.....-.-.-..------ 126 64.—Lasioderma, serricorme: head of larva......-.-..--.- -s.sse ee 126 INTRODUCTION. On an average, from 500 to 600 letters of inquiry are received at this office each month. A very considerable number of these inquiries relate to insects which are found in houses and which either annoy the occupants by their direct attacks or are injurious to household goods and provisions. The available literature on this class of insects is not extensive. Prof. C. H. Fernald, of the Massachusetts Agricultural Experiment Station, published a short bulletin on the general subject some three years ago, but only a few of the most prominent insects of this class were treated. Other American articles are scattered in various publications, in the reports of the State entomologists and bulletins of the entomologists of the State agricultural experiment stations, and in the entomological and other scientific journals. A small volume was published in England in 1893, which bears the title of Our Household Insects, by Mr. Edward A. Butler, a competent entomologist, who has brought together a mass of interesting facts, This little volume, however, treats of English insects only. There is abundant room, then, for the present publication. Much that is pre- sented herewith is based upon original observations in the office, and all accessible publications upon the species treated have been consulted. As will be observed from the title-page, the preparation of the bulletin has been the joint work of the writer and of Messrs. Marlatt and Chit- tenden. Mr. Chittenden’s work has been confined to a concluding chapter on the subject of the species that affect dry vegetable foods, a labor for which he is particularly well fitted by reason of his long study of these species. There has been no systematic division in the work of the main portion of the bulletin between the writer and Mr. Marlatt. Each of us has chosen the topics in which he felt especially interested. It results that longer or shorter articles by one or the other are arranged according to the proper position of the topic in the scheme as a whole and are not brought together under the respective authors. The authorship of the individual articles, however, may be readily accredited by the fact that not only is it displayed in the table of contents, but by the further fact that the contributions are initialed in every case. The very curious but not unexpected condition has been shown in the preparation of this bulletin that of some of our commonest house: hold insects the life history is not known with any degree of exactness. 7 § INTRODUCTION. Of such common species as the household centipede (Scutigera forceps) and the “silver fish” or “ slicker” (Lepisma spp.) careful studies yet remain to be made, and it is hoped that one of the incidental benefits which will result from the publication of this bulletin will be this indi- cation of topics of desired investigation to students. The illustrations have all been made by Miss Sullivan, with the exception of those of the cheese skipper and ham beetles and the house centipede, which have been prepared by Mr. Otto Heidemann. All drawings have been made under the supervision of the author of the section in which they appear. L: Ov fd eRINCIPAL HOUSEHOLD-INSECTS OF THE WNTTED ATES: CHAPTER I. MOSQUITOES AND FLEAS. By L. O. HOWARD. MOSQUITOES. (Culicide spp.) Although mosquitoes are out-of-door insects, they may be considered appropriately under the head of household pests, for the reason that they enter houses, to the torment of the inhabitants, all through the Summer months, and many of them pass the winter in cellars. In fact, it is probably safe to say that no distinctive household pest causes as much annoyance as the mosquito. We are accustomed to think and speak of the mosquito as if there were but one species; yet, to our knowledge, there are no less than eight species, for example, which are more or less common in the Dis- trict of Columbia, and the writer has noticed at New Orleans, La., certainly four different species at the same season of the year, while at Christmas time a fifth species, smaller than the others, causes consid- erable trouble in the houses of that city. In Trinidad Mr. Urich states that he has observed at least ten different species from the island of St. Vincent. In his Catalogue of the Diptera of North America Baron Osten Sacken records twenty-one from North America, and it is per- haps safe to say that not half of the species are described. In the collection of the United States National Museum there are twenty distinct species, all of which have been authentically determined by Mr. Coquillett. The common species at Washington in the months of May and June is Culex pungens Wied. I say the common species, but do not wish to be understood as saying that mosquitoes are common in Washington at that time of the year. Asa matter of fact, the city is singularly free from this little pest, and this is largely due to the reclamation of the marshes of the Potomac River, which in war times and for a number of years afterwards caused the inhabitants of this city to suffer severely from this insect. As late as 1875, it is said, it was almost impossible to spend any of the night hours near the marshes without smudges. Later in the season other species become abundant. 9 10 PRINCIPAL HOUSEHOLD INSECTS. The writer, in the course of certain observations, has carried C. pun- gens through approximately two generations in the early part of the season. It is strange that recent and definite observations upon acecu- Fic. 1.—Culex pungens: a, female, from side; 0, male, from above; c, front tarsus of same; d, middle tarsus; e, hind tarsus; f, genitalia of same; g, scales from hind border of wing; h, scales from disk of wing—enlarged (original). rately determined species of many of our commonest insects have not been published. This is mainly due to the fact that most entomologists havea way of saving time by following the observations of older writers. MOSQUITOES AND FLEAS. il. This is all well enough where the species and the conditions are identi- cal, but when, as is the case with such an insect as that under observa- tion, the principal observations were made upon a different, though congeneric, species, and in another part of the globe, where climatic and other conditions differ, the custom is unfortunate. There is not, in any of our published works, a thoroughly satisfactory figure of a well- determined species of mosquito, or of its earlier stages. The statements quoted in the text-books and manuals date back, in general, to the time of Réaumur, one hundred and fifty years ago. These observations were made in the month of May, upon a species (Culex pipiens) which does not occur in North America, and in the one locality of Paris, France. The notes made upon C. pungens at Washington possess, therefore, some scientific importance. Fic. 2.—Culex pungens: Egg-mass above in center; young larva, greatly enlarged, at right; young larve, not so much enlarged, below; enlarged eggs above at left (original). The operation of egg-laying was not observed, but it probably takes place in the very early morning hours. The eggs are laid in the usual boat-shaped mass, just as those of C. pipiens, as described by Réaumur. We say boat-shaped mass, because that is the ordinary expression. As a matter of fact, however, the egg masses are of all sorts of shapes. The most common one is the pointed ellipse, convex below and concave above, all the eggs perpendicular, in six to thirteen longitudinal rows, with from 3 or 4to 40eggsinarow. The number of eggs in each batch varies from 200 to 400. Asseen from above, the egg-mass is gray brown; from below, silvery white, the latter appearance being due to the air film. It seems impossible to wet these egg masses. They may be pushed under water, but bob up, apparently as dry as ever. The egg mass Separates rather regularly and the eggs are not stuck together 312 PRINCIPAL HOUSEHOLD INSECTS. very firmly. After they have hatched the mass will disintegrate in a few days, even in perfectly still water. The individual eggs are 0.7 mm. in length and 0.16 mm. in diameter at the base. They are slender, broader and blunt at bottom, slenderer and somewhat pointed at tip. The tip is always dark grayish brown in color, while the rest of the egg is dirty white. Repeated observations show that the eggs hatch, under advantageous conditions, certainly as soon as sixteen hours. Water buckets containing no egg masses, placed out at night, were found to contain egg masses at 8 o’clock in the morning, which, as above stated, were probably laid in the early morning, before daylight. These eggs, the third week in May, began to hatch quite regularly at 2 o’clock in the afternoon of the same day on warm days. In cooler weather they sometimes remained unhatched until the second day. If we apply the evidence of European observers to this species, the period of the egg state may be under twelve hours; but there is a possibility that they are laid earlier in the night, which accounts for the fact that sixteen hours is the shortest period which we can definitely mention. The larve issue from the underside of the egg masses, and are ex- tremely active at birth. When first observed it is easy to fall into an error regarding the length of time which they can remain under water, or rather without coming to the surface to breathe, since, in striving to come to the surface for air, many of them will strike the underside of the egg mass and remain there for many minutes. It is altogether likely, however, that they get air at this point through the eggs or through the air film by which the egg mass is surrounded, and that they are as readily drowned by continuous immersion as are the older ones, as will be shown later. One of the first peculiarities which strikes one on observing these newly hatched larvee under the lens is that the tufts of filaments which are conspicuous at the mouth are in absolutely constant vibration. This peculiarity, and the wriggling of the larve through the water, and their great activity, render them interesting objects of study. In gen- eral, the larvee, passing through apparently three different stages, reach maturity and transform to pups in a minimum of seven days. When nearly full grown their movements were studied with more care, as they were easier to observe than when newly hatched. At this time the larva remains near the surface of the water, with its respiratory siphon at the exact surface and its mouth filaments in constant vibra. tion, directing food into the mouth cavity. Occasionally the larva descends to the bottom, but, though repeatedly timed, a healthy indi- vidual was never seen to remain voluntarily below the surface more than a minute. In ascending it comes up with an effort, with a series of jerks and wrigglings with its tail. It descends without effort, but ascends with difficulty; in other words, its specific gravity seems to be greater than that of the water. As soon, however, as the respiratory MOSQUITOES AND FLEAS. rs siphon reaches the surface, fresh air flows into its trachee, and the physical properties of the so-called surface film of the water assist it in maintaining its position. The account by Miall, in his recently published Natural History of Aquatic Insects, is misleading, for the reason that he assumes that the emd of the body, with its four (or,as he has it, five) leaf-like expansions, is the breathing organ. Asa matter of fact, as is plainly shown by fig. 2, this end of the body does not reach the surface, and it is the tip of the respiratory siphon only which is extended to the air. This respiratory tube takes its origin from the tip of the eighth abdominal segment, and the very large trachee can be seen extending to its extremity, where they have a double orifice. The ninth segment of the abdomen is armed at the tip with four flaps and six hairs,as shown in fig. 4. These flaps are gill-like in appearance, though they are prob- ably simply locomotory in function. With so remarkably developed an \i Fic. 3.—Culex pungens: Head of larva from below at left; same from above at right—greatly enlarged (original). apparatus for direct air breathing there is no necessity for gill struct- ures. Raschke! and Hurst? consider that the larva breathes both by the anus and by these giil flaps, as weil as by the large trachez which open at the tip of the respiratory tube. Naschke considers that these trachee are so unnecessarily large that they possess a hydrostatic function. The writer is inclined to believe that the gill flaps may be functional as branchial structures in the young larva, but that they largely lose this office in later life. | After seven or eight days, at a minimum, as just stated, the larva transforms to pupa. The pupa, as has been repeatedly pointed out with other species, differs most pronouncedly from the larva in the great swelling of the thoracic segments. In this stage the insect is 'Raschke, Die Larve von Culex nemorosus, Berlin, 1887. 2 Hurst, The Pupal Stage of Culex, Manchester, 1890. 14 PRINCIPAL HOUSEHOLD INSECTS. lighter than water. It remains motionless at the surface,and when disturbed does not sink without effort, as does the larva, but is only able to descend by a violent muscular action. It wriggles and swims as actively as does the larva, and soon reaches the bottom of the jar or breeding place. As soon as it ceases to exert itself, however, it floats gradually up to the surface of the water again. .The fact, how- ever, that the larva, after itis once below the surface of the water, sinks rather than rises, accounts for the death of many individuals. If they become sick or weak, or for any reason are unable to exert sufficient muscular force to wriggle to the surface at frequent intervals, they will actually drown, and the writer has seen many of them die in this way. It seems almost like a contradiction in terms to speak of an aquatic insect drowning, but this is a frequent cause of mortality among wrig- glers. This fact also explains the efficacy of the remedial treatment which causes the surface of the water to become covered with a film of oil of any kind. Aside from the actual insecticide effect of the oil, the larve drown from not being able toreach the air. The structure of the pupa differs in no material respect from that of corresponding stages of European species, as so admirably figured and described by the older writers, notably Réaumur and Swammerdam,' and needs no description in view of the care with which the figures accompanying this article have been drawn. The air tubes no longer open at the anal end of the body, but through two trumpet-shaped sclerites on the thorax, from which it results that the pupa remains upright at the surface, instead of with the head downward. There is a very apparent object in this reversal of the position of the body, since the adult insect issues from the thorax and needs the floating skin to supportitself while its wings are expanding. In general, the adult insects issue from the pupe that are two days old. This gives what is probably the minimum generation for this species as ten days, namely, sixteen to twenty-four hours for the egg, seven days for the larva, and two days for the pupa. The individuals emerging on the first day were invariably males. On the second day the great majority were males, but there were also a few females. The preponderance of males continued to hold for three days; later the females were in the majority. In confinement the males died quickly; several lived for four days, but none for more than that period. The females, however, lived for a much longer time. .Some were kept alive without food, in a confined space of not more than 4 inches deep by 6 across, for three weeks. But one egg mass was deposited in confine- ment. This was deposited on the morning of June 30 by a female which issued from the pupa June 27. No further observations were made upon the time elapsing between the emergence of the female and the laying of the eggs. but in no case, probably, does it exceed a few days. 1 Even Bonanni, in 1691, gave very fair figures of the larva and pupa of a European species. Micrographia Curiosa, Rome, MDCXCI, Pars. II, Tab. I. MOSQUITOES AND FLEAS. | 15 The length of time which elapses for a generation, which we have just mentioned, is almost indefinitely enlarged if the weather be cool. Asa matter of fact, a long spell of cool weather followed the issuing of the adults just mentioned. Larve were watched for twenty days, dur- ing which time they did not reach full growth. The extreme shortness of this June generation is significant. It accounts for the fact that swarms of mosquitoes may develop upon occasion in surface pools of rain water, which may dry up entirely in ~° Fic. 4.—Culex pungens: Full-grown larva at left; pupa at right above, its anal segment below—all greatly enlarged (original). the course of two weeks, or in a chance bucket of water left undis- turbed for that length of time. Further, the shortness of this genera- tion was, while not unexpected, not at all in accordance with any pub- lished statements as to the length of life of any immature mosquito of any species. But these published statements, as previously shown, were nearly all based upon observations made in a colder climate and in the month of May. On August 1 Mr. F. C. Pratt, an assistant in the division of ento- 16 PRINCIPAL HOUSEHOLD INSECTS. mology, brought in from Lakeland, Md., a small place 9 miles from Washington, specimens of a large and very ferocious mosquito, which Mr. Coquillett determined as Anopheles quadrimaculatus Say, a species which had previously been observed at Washington in August. This mosquito was very abundant at Lakeland at the time, and its eggs were obtained, but rearing operations were interrupted by absence from Washington. At the same time the commonest of the mosquitoes at Washington was found to be Culex consobrinus. This latter species was one which was studied by the writer in 1892 in the Catskill Moun- tains, near Tannersville, Greene County, N. Y. This species in Wash- ington became, during August, more abundant than C. pungens. Octo- ber 25, however, the writer found both species in his house, which they had evidently entered for hibernation. In 1893 several specimens of pungens were taken in the month of January in the cellar of his house in Georgetown. This hibernation in cellars as well as in outhouses is very common, although it is not frequently referred to. Specimens of C. consobrinus were received in November, 1894, from J. M. Wade, of Boston, with the statement that they were abundant in his cellar in that city. The cellar was very cold, although in one corner there was a tin furnace pipe. The mosquitoes avoided the warm corner, and were always thickest in the cold parts of the cellar. So abundant were they that if a lamp were held up the inside of the chimney would soon be covered half an inch thick with their bodies. The degree of cold seems to make no difference with this successful hibernation. Arctic explorers have long since recorded the abundance of mosquitoes in the extreme north. In the narrative of C. F. Hall’s second arctic expedition the statementis made that mosquitoes appeared on the 7th of July, 1869, in extraordinary abundance. Dr. E. Sterling, of Cleveland, Ohio, has sent us an account of the appearance of mos- quitoes by thousands in March, 1844, when he was on a snowshoe trip from Mackinaw to Sault Ste. Marie. Their extraordinary numbers at this season of the year is remarkable, indicating a most plentiful hibernation. Mr. H. Stewart, of North Carolina, has written us of a Similar experience on the north shore of Lake Superior in 1866. On warm days in March, when the snow was several feet deep and the ice on the lake 5 feet in thickness, mosquitoes appeared in swarms, ‘literally blackening the banks of snow in the sheltered places.” The Indians told Mr. Stewart that the mosquitoes lived through the winter, and . that the old ones were the most annoying to them. May 9, 1896, Mr. Lugger sent the writer from St. Anthony Park, Minn., specimens of C. consobrinus, stating that it came in a genuine swarm in April, with a heavy snowstorm, at a time when all of the lakes were covered with ice—“‘ Minnesota’s most certain crop.” It is a well-known fact that the adult male mosquito does not neces- sarily take nourishment, and that the adult female does not necessarily _ rely upon the blood of warm-blooded animals. They are plant feeders MOSQUITOES AND FLEAS. 1G) and have also been recorded as feeding upon insects. Dr. Hagen men- tions taking a species in the Northwest feeding upon the chrysalis of a butterfly, while scattered through the seven volumes of Insect Life are a number of records of observations of a vegetarian habit, one writer stating that he has seen them with their beaks inserted in boiled potatoes on the table, and another that he has seen watermelon rinds with many mosquitoes settled upon them and busily engaged in sucking the juices. Mosquitoes undoubtedly feed normally on the juices of plants, and not one in a million ever gets an opportunity to taste the blood of a warm-blooded animal. When we think of the enormous tracts of marsh land into which warm-blooded animals never pene- trate, and in which mosquitoes are breeding in countless numbers, the truth of this statement becomes apparent. The males have been observed sipping at drops of water, and one instance of a fondness for molasses has been recorded. Mr. EK. A. Schwarz has observed one drinking beer. The literature of popular entomology is full of instances of the enor- mous numbers in which mosquitoes occasionally occur, but a new instance may not be out of place here. Mr. Schwarz tells the writer that he has never seen, even in New Jersey, mosquitoes to compare in numbers with those at Corpus Christi, Tex. When the wind blows from any other direction than south, he says, hundreds of thousands of mil- lions of mosquitoes blow in upon the town. Great herds of hundreds of horses run before the mosquitoes in order to get to the water. With a change of wind, however, the mosquitoes blow away.. REMEDIES AGAINST MOSQUITOES. _ Of the remedies in use in houses the burning of pyrethrum powder and the catching of the mosquitoes on the walls with kerosene in cups, as déscribed in Insect Life (Vol. V, p. 143), are probably the best, next to a thorough screening and mosquito bars about the bed. It may be of interest to mention incidentally a remedy in use among the Chinese, as recorded in Robert Fortune’s ‘‘ Residence Among the Chinese: Scenes and Adventures Among the Chinese in 1853-1856” (London, 1857). Long-necked bags of paper, half an inch in diameter and 2 feet long, are filled with the following substances: Hither pine or juniper sawdust, mixed with a small quantity of ‘‘nu-wang” and 1 ounce of arsenic. These substances are well mixed and run into the bags in a dry state; each bag’is coiled like a snake and wrapped and tied with thread. The outer end is lighted and the coil laid on a board. Two coils are suffi- cient for an ordinary-sized room, and 100 coils sell for 6 cents. Mr. Mun Yen Chung, of the Chinese legation, has been good enough to inform the writer that by “‘nu-wang” Mr. Fortune probably meant liu-wang (brimstone). Altogether the most satisfactory ways of fighting mosquitoes are those which result in the destruction of the larvee or the abolition of 2805—No. = 2 18 PRINCIPAL HOUSEHOLD INSECTS. their breeding places. Innot every locality are these measures feasible, but in many places there is absolutely no necessity for the mosquito annoyance. The three main preventive measures are the draining of breeding places, the introduction of small fish into fishless breeding places, and the treatment of such pools with kerosene. These are three alternatives, any one of which will be efficacious, and any one of which - may be used where there are reasons against the trial of the others. In 1892 the writer published the first account of extensive out of-doors experiments to determine the actual effect upon the mosquitoes of a thin layer of kerosene upon the surface of water in breeding pools and the relative amount to be used. He showed the quantity of kerosene necessary for a given water surface, and demonstrated further that not only are the larve and pup thereby destroyed almost immedi- ately, but that the female mosquitoes are not deterred from attempt- ing to oviposit upon the surface of the water, and that they are thus destroyed in large numbers before their eggs are laid. He also showed approximately the length of time for which one such treatment would remain operative. No originality was claimed for the suggestion, but only for the more or less exact experimentation. The writer himself, as early as 1867, had found that kerosene would kill mosquito larve, and the same knowledge was probably put in practice, although without publicity, in other parts of the country. In fact, Mr. H. EK. Weed states (Insect Life, Vol. VII, p. 212) that in the French quarter of New Orleans it has been a common practice for many years to place kerosene in the water tanks to lessen the numbers of mosquitoes in a given locality, although he knew nothing that had been written to show that such was the case, and he says: ‘In this age of advancement we can no longer go by hearsay evidence.” Suggestions as to the use of kerosene, and even experiments on a water surface 10 inches square, showing that the larve could be killed by kerosene, were recorded by Mrs. C. B. Aaron in her Lamborn prize essay and published in the work entitled ‘¢ Dragon Flies versus Mosquitoes” (D. Appleton & Co., 1890). Mr. W. Beutenmiiller also in the same work made the same suggestion. The quantity of kerosene to be practically used, as shown by the writer’s experiments, is approximately 1 ounce to 15 square feet of water surface, and ordinarily the application need not be renewed for one month. Since 1892 several demonstrations, on both a large and a small scale, have been made. Two localities were rid of the mosquito plague under the supervision of the writer by the use of kerosene alone. Mr. Weed, in the article above mentioned, states that he rid the college campus of the Mississippi Agricultural College of mosquitoes by the treatment with kerosene of eleven large water tanks. Dr. John B. Smith has recorded, though without details, success with this remedy in two cases on Long Island (Insect Life, Vol. VI, p. 91). Prof. J. H. Comstock tells the writer that a similar series of experiments, with perfectly satisfactory results, was carried out by Mr. Vernon L. Kel- logg on the campus of Stanford University, at Palo Alto, Cal. In this MOSQUITOES AND FLEAS. 19 ease post holes filled with surface water were treated, with the result that the mosquito plague was almost immediately alleviated. Additional experiments on a somewhat larger scale have been made by Rey. John D. Long at Oak Island Beach, Long Island Sound, and by Mr. W. R. Hopson, near Bridgeport, Conn., also on the shores of Long Island Sound, the experiments in both cases indicating the effi- eacy of the remedy when applied intelligently. I have not been able to learn the details of Mr. Hopson’s operations, but am told that they included extensive draining as well as the use of kerosene. It is not, however, the great sea marshes along the coast, where mos- quitoes breed in countless numbers, which we can expect to treat by this method, but the inland places, where the mosquito supply is derived from comparatively small swamps and circumscribed pools. In most localities people endure the torment or direct their remedies against the adult insect only, without the slightest attempt to investigate the source of the supply, when the very first step should be the undertak- ing of such an investigation. In “Gleanings in Bee Culture” (October 1, 1895) we notice the statement in the California column that in some California towns the pit or vault behind water-closets is subject to flushing with water during the irrigation of the land near by. A period of several weeks elapses before more water is turned in, and in the meantime the water becomes stagnant and the breeding place of millions of mosquitoes. Then, as the correspondent says, ‘‘people go around wondering where all the mosquitoes come from, put up screens, burn buhach, and make a great fuss.” Nothing could be easier than to pour an ounce of kerosene into each of these pits, and all danger from mosquitoes will have passed. In many houses in Baltimore, Md., the sewage drains first into wells or sinks in the backyard, and thence in some cases into sewers, and in other cases is pumped out periodically. These wells invariably have open privies built over them, and the mosquitoes, which breed in the stagnant contents of the sinks, have free egress into the open air back of the houses. Hence parts of Baltimore much further removed from either running or stagnant water than certain parts of Washington, where no mosquitoes are found, are terribly mosquito ridden, and sleep without mosquito bars is, from May to December, almost impossible. Specimens of Culex pungens captured November 5 in such a privy as described have been brought to the writer from Baltimore by one of his assistants, Mr. R. M. Reese. Kerosene has been tried by Mr. Reese in one case in Baltimore, and two treatments of a privy made about May 1 and June 1, respectively; seemed to diminish the numbers of the pest in that particular house; but without concerted action of all the householders in a given block (all the houses, be it remembered, being exactly alike in the method of Sewage disposal) no great amount of good could be accomplished. With such concerted action, however, there seems to be no reason why 20 PRINCIPAL HOUSEHOLD INSECTS. the mosquito plague could not be greatly diminished in many, if not most, parts of Baltimore at a very small expense. Usually one well serves two houses, the privies being built in pairs, so that one treatment would suffice for two dwellings. On ponds of any size the quickest and most perfect method of form- ing a film of kerosene will be to spray the oil over the surface of the water. The remedy which depends upon draining breeding places needs ne extended discussion. Naturally the draining off of the water of pools will prevent mosquitoes from breeding there, and the possibility of such draining and the means by which it may be done will vary with each individual case. The writer is informed that an elaborate bit of work which has been done at Virginia Beach bears on this method. Behind the hotels at this place, the hotels themselves fronting upon the beach, was a large fresh-water lake, which, with its adjoining Swamps, was a source of mosquito supply, and it was further feared that it made the neighborhood malarious. Two canals were cut from the lake to the ocean, and by means of machinery the water of the lake was changed from a body of fresh to a body of salt water. Water that is somewhat brackish will support mosquitoes, but water which . is purely salt will destroy them. The introduction of fish into fishless breeding places is another mat- ter. It may be undesirable to treat certain breeding places with kero- sene, aS, for instance, water which is intended for drinking, although this has been done without harm in tanks where, as is customary, the drinking supply is drawn from the bottom of the tank. An interesting case noted in Insect Life (Vol. IV, p. 223), in which a pair of carp was placed in each of several tanks, in the Riviera, is a case in point. The value of most small fishes for the purpose of destroying mosquito larvee was well indicated by an experience described to us by Mr. C. H. Russell, of Bridgeport, Conn. In this casea very high tide broke away a dike and flooded the salt meadows of Stratford, a small town a few miles from Bridgeport. The receding tide left two small lakes, nearly side by side and of the same size. In one lake the tide left a dozen or more small fishes, while the other was fishless. An examination by Mr. Russell in the summer of 1891 showed that while the fishless lake contained tens of thousands of mosquito larve, that containing the fish had no larve. The use of carp for this purpose has been mentioned in the preceding paragraph, but most small fish will answer as well. The writer knows of none that will be better than either of the common little stickle- backs (Gasterosteus aculeatus or Pygosteus pungitius). They are small, but very active and very voracious. Mr. F. W. Urich, of Trinidad, has written us that there is a little cyprinoid common in that island which answers admirably for this purpose. This fish has not been specifically determined, but we hope to make an effort to introduce it MOSQUITOES AND FLEAS. 21 into our Southern States, if it proves to be new to our fauna. At Bee- ville, Tex., a little fish is used for this purpose which is there called a perch, although we have not been able to find out just what the species is. They soon eat up the mosquito larve, however, and in order to keep them alive the people adopt an ingenious fly trap, which they keep in their houses and in which about a quart of flies a day is caught. These flies are then fed to the fish. This makes a little circle which strikes us as particularly ingenious and pleasant. The fly traps catch the flies and rid the house of that pest. The flies are fed to the fish in the water tanks and keep them alive in order that they may feed on the mosquito larvee, thus keeping the houses free of mosquitoes. Where kerosene is considered objectionable, and where fish can not be readily obtained, there is another course left open. It is the con- stant artificial agitation of the water, since mosquitoes will oviposit only in still water. At San Diego, Tex., in the summer there are no streams for many miles, but plenty of mosquitoes breed in the water tanks. Some enterprising individuals keep their tanks free by putting in a little wheel, which is turned by the windmill, and keeps the water almost constantly agitated. THE MOSQUITOES OF THE COUNTRY AT LARGE. In the introductory paragraph the writer has indicated that we have numerous species among the mosquitoes of the United States and that several different species may occur in the same locality. It happens, however, that no definite knowledge exists, even among entomologists as to the exact species which may be found in any given locality. The desirability of a careful study of our mosquitoes is therefore apparent. As a preliminary step, the writer borrowed all of the mosquitoes from the collections of Prof. Lawrence Bruner, of the University of Nebraska, Lincoln, Nebr.; Prof. J. H. Comstock, of Cornell University, Ithaca, N. Y.; Prof. H. Garman, of the agricultural experiment station at Lexington, Ky.; Prof. C. P. Gillette, agricultural experiment station, Fort Collins, Colo.; Prof. C. W. Johnson, Wagner Free Institute, Phil- adelphia, Pa.; Prof. Otto Lugger, agricultural experiment station, St. Anthony Park, Minn.; Dr. W. A. Nason, Algonquin, Ill., and Mr. Th. Pergande, Washington, D.C. The material thus received, together with the collection of Culicide of the department of insects in the National Museum, was placed in the hands of Mr. D. W. Coquillett for Specific study. The results of this study were interesting. Mr. Coquillett had under his hands mosquitoes from nearly all portions of the United States. He found that the material represented twenty different species, of five genera, and was able to make out some important synonymical facts. In the distribution of certain species the results were unexpected. It was found that some of the commoner forms, viz, Culex consobrinus, C. excitans, C. perturbans, OC. posticatus, C. pungens, Prosophora ciliata, Fe PRINCIPAL -HOUSEHOLD INSECTS. Anopheles punctipennis, and A. quadrimaculata, occur all over the country, from New England to Texas, and even to southern California. In almost any given locality in the United States, therefore, one would probably be able to find all of these eight species, with perhaps two or three additional ones. The list which follows was drawn up by Mr. Coquillett, and embodies, in part, the results of his studies. It must be remembered that, after all, the material was scanty, since no one has taken the trouble to thoroughly collect mosquitoes. The list represents, however, a distinct and important advance ou our former knowledge of these annoying creatures. LIST OF THE MOSQUITOES OF THE UNITED STATES. (A) Species examined by D. W. Coquillett. Culex consobrinus Desy. 3 males, 18 females. Synonyms: Culex punctor Kirby; C. impatiens Walk.; C. pinguis Walk.; C. inor- natus Will. (the latter synonymy based on a study of one of Williston’s co- type specimens). Habitat: White Mountains, N. H.; Beverly, Mass., September 28 (Nat. Mus.); Catskill Mountains, Greene County, N. Y., 2,500 feet (Howard) ; Illinois, March 21, April 29, May 6, October 16 (Nason); St. Anthony Park, Minn., April, May, on snow (Lugger); Saskatchewan River, British America; South Dakota (Nat. Mus.); Lincoln, Nebr., May, September (Bruner); Colorado (Nat. Mus.); Los Angeles, Cal., February (Coquillett) ; Argus Mountains, Cal., April (Nat. Mus.) ; Santa Fé, N. Mex., July (Cockerell). Culex excitans Walk. 3 males, 2 females. Habitat: New Bedford, Mass. (Johnson); Lincoln, Nebr., May (Bruner); Santa Fé, N. Mex., July (Cockerell). Culex excrucians Walk. 3 females. Habitat: Ithaca, N. Y., July 14 (Comstock). Culex fasciatus Fabr. 4 males, 2 females. Synonyms: Culex teniatus Wied.; Culex mosquito Desv. (non Arribalzaga). Habitat: Georgia, August (Coquillett) ; Natchitoches, La., October 6 (Johnson) ; Isle of Pines, W. I. (Scudder); Kingston, Jamaica, July 13 (Johnson). Culex impiger Walk. 14 males, 50 females. Synonym: Culex implecabilis Walk. Habitat: White Mountains, N. H.; Beverly, Mass., May 24, June 2 (Nat. Mus.); Ithaca, N. Y., July 9 and 17, August 28; Wilmuth, N. Y., June 10 (Comstock) ; Saskatchewan River, British America (Nat. Mus.); Minnesota (Lugger); . Loudon County, Va., Aug. 26 (Pratt); Tyrone, Ky., July 14 (Garman); Georgia (Nat. Mus.) ; Mesilla, N. Mex., (Cockerell) ; Isle of Pines, W. I. (Scudder); Port- land, Jamaica (Johnson). Culex perturbans Walk. 8 females. Habitat: Lakeland, Md., August 8 (Pratt); Virginia, cae 17 (Pergande) ; Tick Island, Fla., May 12 (Johnson); Texas (Nat. Mus.). Culex posticatus Wied. 5 females. Synonym: Culex musicus Say. Habitat: Montgomery County, Pa., July 17 (Johnson); Texas (Nat. Mus.). Culex pungens Wied. 25 males, 103 females. Habitat: White Mountains, N. H.; Beverly, Mass., September 5; Cambridge, Mass., September 16 to November 5; Boston, Mass.; Baltimore, Md., Novem- ber 5 (Nat. Mus.), November 26 (Lugger); Charlton Heights, Md., December 1 MOSQUITOES AND FLEAS. 23 (Pratt); District of Columbia, January 30, March 5, May 6 anid 15, June 28, July 11, August, October 10, 15, 25, and 31, November 4, 8, 13, 16, and 23, December - 23 (Pergande); Ithaca, N. Y., May 29, July 17, August 28 (Comstock); Illinois (Nason); Minnesota (Lugger); Lincoln, Nebr., September 20 (Bruner); Lex- ington, Ky., November 10 (Garman); New Orleans, La., December 17 (Howard) ; San Antonio, Tex., May 5 (Marlatt); Georgia, August (Coquillett); Portland, Jamaica (Johnson). Culex signifer Coq. 1 female. Habitat: District of Columbia, June (Coquillett). Culex stimulans Walk. 13 males, 54 females. Habitat: White Mountains, N. H.; Beverly, Mass., June 2, July 9; Cambridge, Mass., May; Jamaica Plain, Mass., August 25 (Nat. Mus.); Baltimore, Md. (Lugger); Illinois, August 1, September 15, October 5 (Nason); Agricultural College, Mich. (Gillette); Saskatchewan River, British America (Nat. Mus.); Lincoln, Nebr. (Bruner); Colorado (Nat. Mus.); Ithaca, N. Y., June 13, 18, 29, July 14, August 28; Wilmuth, N. Y., June 10 (Comstock); Georgia (Nat. Mus.). Culex tarsalis Cog. 1 male, 4 females. Habitat: Argus Mountains, Cal., April; Folsom, Cal., July 3 (Nat. Mus.). Culex triseriata Say. 3 females. Habitat: White Mountains,N. H. (Nat. Mus.); Delaware County, Pa., June 12 (Johnson); Washington, D. C., May 5, Loudon County, Va. (Pratt). Culex tzeniorhynchus Wied. 1 male, 32 females. (Not the Culex teniorhynchus Wied. of Arribalzaga.) Habitat: Maine, August; Beverly, Mass., June, September 15° (Nat. Mus.); Avalon, Anglesea, and batt City, N. J., July 10 to 29 (Johnson); Far Bocaway. Long Island, N. Y., Aug. 30 Geonrard District of Columbia (Pergande); Georgia (Nat. Mus.); St. Augustine and Charlotte Harbor, Fla., July; Portland, Jamaica (Johnson). Psorophora ciliata Fabr. 2 males, 29 females. Habitat: Dorchester, Mass. (Nat. Mus.); Washington, D. C. (Chittenden); Westville, N. J., July 2 (Johnson); Illinois (Nason); Brooklyn Bridge, Ky., June 23 (Garman); Lincoln, Nebr., July, August (Bruner); Los Angeles, Cal. (Coquillett); San Diego, Tex., May 15 (Schwarz); Florida, July (Nat. Mus.). Anopheles crucians Wied. 3 females. Habitat: District of Columbia, April 27 (Pergande); Georgia (Nat. Mus. No Anopheles punctipennis Say. 5 males, 13 females. (Considered by Wiedemann to be the same species as his Anopheles crucians, but the two are certainly distinct. ) Synonym: Culex hyemalis Fitch (wrongly referred to Anopheles quadrimaculata in the Osten Sacken Catalogue). Habitat: Castleton, Vt., February 1 (temperature 6° F.); Beverly, Mass., Sep- tember 19, October 2; Cambridge, Mass., June 16, September 30, October 20 (Nat. Mus.); Charlton Heights, Md., March 31, November 17 (Pratt); District of Columbia, June 6, October 15, 25, and 31 (Pergande); Philadelphia, Pa., October 12 (Johnson); Ithaca, N.Y., April 17, August 28 (Comstock); Illinois, October 16 (Nason); Texas (Nat. Mus.); Mesilla, N. Mex. (Cockerell); Port- land, Jamaica (Johnson). Anopheles quadrimaculata Say. 3 males, 31 females. Habitat: Berlin Falls, N. H., August (Nat. Mus.); Ithaca, N. Y., January, ie 31, November 28 (Comstock): Lakeland, Md., August 8; Chartean Heights, Md., November 24 (Pratt); District of Golamnbie: July, Outober 15, November 2 and 14 (Pergande); [llinois, September 10, October 10 (Nason); St. Anthony Park, Minn., December 11 (Lugger); Tick Island, Fla., May 12 (Johnson); Texas (Nat, Mus.). 24 PRINCIPAL HOUSEHOLD INSECTS. Megarhinus ferox Wied. 1 male. Habitat: District of Columbia, August 22 (Pergande). Megarhinus rutilus Coq. 3 males, 5 females. Habitat: North Carolina; Georgiana, Fla. (Nat. Mus.). Aédes sapphirinus Q.S. 1 female. Habitat: Ithaca, N. Y. (Comstock). (B) Species recorded from the United States, but not included in the material studied. Culex rubidus Desvoidy, Culicides, etc. Carolina. Culex testaceus v. d. Wulp, Tijdschr. v. Entom., 2d ser., II, 128, Tab. III, f.1. Wis- consin. Culex incidens Thomson, Eugenie’s Resa, etc., 443. California. Culex territans Walker, Dipt. Saund., 428. United States. Psorophora boscii Desvoidy, Culicides, ete. Carolina. Anopheles annulimanus v. d. Wulp, Tijdschr. v. Entom., 2d ser., II, 129, Tab. III, f. 2. Wisconsin. : Anopheles ferruginosus Wiedemann, Auss. Zw., I, 12. New Orleans (Wied.); on the Mississippi (Say). Culex quinquefasciatus Say, Journ. Ac. Phil., III, 10, 2; Compl. Wr., II, 39. (Change of name by Wied.) Anopheles maculipennis Meigen (European species, which also oceurs in North America, according to Loew, Sillim. Journ., n. ser., Vol. XXXVII, 317). Anopheles nigripes Staeger (European species, which also occurs in North America, according td’ Loew, Sillim. Journ., n. ser., Vol. XX XVII, 317). Aédes fuscus O. Sacken, Western Diptera, 191. Cambridge, Mass. THE CAT AND DOG FLEA. (Pulex serraticeps Gerv.) Examination of many specimens of fleas sent to the Department in recent years shows that the species which commonly overruns houses during the damp summers, in our Eastern cities at least, is not, as many have supposed, the human flea (Pulex irritans), but the common cos- mopolitan flea of the dog and the cat (Pulex serraticeps). There is wide- spread ignorance as to the transformations of this insect, and even the average entomologist is puzzled to know where to consult good figures of the different stages and a detailed account of the life history. The figures accompanying this article have been prepared to fill this want, and the following account of the transformations has been drawn up from notes made during the summer of 1895, at the request of the writer, by Mr. Pergande, of the division of entomology. The best two of the previously published articles are, one by Laboulbene, in the Annales de la Société Entomologique de France, 1872, pp. 267-273, PI. XIII, and the other by W. J. Simmons, read before the Microscopical Society of Calcutta, March 5, 1888, and printed in The American Monthly Microscopical Journal for December, 1888, with no illustra- tions.? 1Ritzema has written an article on the natural history of the dog flea, which, however, could not be consulted by the writer. MOSQUITOES AND FLEAS. 25 Laboulbéne describes carefully the pretty, oval, waxy white or opaque, porcelain-colored, smooth egg, which reaches 0.5 mm. in length. He describes the external appearance of the larve and recites their extremely rapid movements, which are made by means of the bristles with which they are furnished, and particularly by means of the tubercle and the hair-like spines below the head. He placed larve upon dust, with birds’ feathers mixed with dried blood, upon which they developed perfectly. Others were put on the sweepings of aroom, and developed just as well. Laboulbene at first believed that blood was necessary for the nourishment of the larvae, the reddish-colored contents of the digestive tract making him think so; but he found they would flourish and complete their metamorphoses in sweepings in which there was no trace of blood. He concluded that all that has been said on Pulex irritans nourishing its young on dried blood is very problem- Fic. 5.—-Pulez serraticeps ; a, egg; b, larva in cocoon; ¢, pupa; d, adult; e, mouth-parts of same from side; f, labium of same from below; g, antenna of same—all enlarged (original). atical. In his opinion the larve of the cat flea for the most part live upon the ground in spots where cats stay, and that they live in the dust in the cracks of the floor. The cocoon he described as ovoid, almost rounded, brown and granular, because it is covered with dust, delicate, but difficult to open, attached by one surface. It is about 2.5mm. by 2.75mm. The only statement in the article regarding the length of the different stages is to the effect that the pupal condition lasts from one to two weeks. Mr. Simmons found the eggs upon a cloth upon which a dog had been sleeping, in the midst of a dust composed of fragments of cuticle, hairs, fibers, and pellets of dried blood, the last being probably the nat- ural excreta of the fleas. In fifty hours most of the eggs hatched. The larve are described, and the statement is made that in seven days they began to spin their cocoons. They remained in the cocoons eight days, 26 PRINCIPAL HOUSEHOLD INSECTS. when the adults emerged, completing their transformations seventeen days after the eggs were deposited. The eggs of the flea under consideration are deposited between the hairs of the infested animals, but are not fastened to them, so that when the animal moves about or lies down numbers of the eggs will be dis- lodged and drop to the ground or the floor or wherever the animal may be at the time. An easy way to collect them, therefore, is to lay a strip of cloth for the animal to sleep upon, and afterwards brush the cloth into a receptacle, in which the eggs will be found in numbers. Some difficulty was found in securing proper conditions of moisture to bring about successful rearing, and some detailed account of our experience will be of vaiue to persons who desire to repeat the rearing in order to secure material for microscopic study, and will be at the same time suggestive as bearing on the conditions under which the insect will multiply in houses. On June 27 a number of eggs were collected and placed in two glass vessels, one large and one small, each containing a layer of sand at the bottom, next a layer of sawdust, and on top of this a layer of rich soil. The eggs were placed between two layers of blotting paper on top of the soil. On June 29 fourteen of the eggs had hatched in the small vessel, and the larve had crawled at once down into the sawdust. On July 1 some of the eggs were found to have hatched in the large vessel, and the alimentary canal of the larve was already brownish, indicating that they had been feeding to some extent and presumably upon the particles of dried blood collected with the eggs and placed with them between the layers of blotting paper. By July 11 all of these larvee in both vessels had died, apparently without having cast a skin. They were very active during most of this period, crawling rapidly about when disturbed. Some were noticed to feed upon particles of peat which was placed with them. From some of these individuals fig.6 was made. On the second antennal joint there was apparent a sensorial spot, and on or near the base of the antennz were two small, slender, fleshy tubercles and a few granulations on each side, some dis- tance behind the antenne. At the base of the head above occurred a small, apparently well-differentiated sclerite, as indicated in fig. 6, b, the purpose of which we can not surmise. Immediately behind it, on the anterior border of the first thoracic segment, is apparently a delicate sculpturing, indicating a thickening of the integument at this point. The posterior border of this segment is a somewhat similar, faintly indicated band. The first nine segments bear each four dorsal bristles and, on each side, one ventro-lateral bristle, near the posterior margin. The two following segments bear each six dorsal bristles and one ventro- lateral bristle, and the penultimate segment eight dorsal and one ven- tral bristle. These bristles become gradually longer toward the end of the body. The last segment is without long bristles, although there is a semicircular transverse row of numerous fine hairs and a small patch MOSQUITOES AND FLEAS. 2% of still finer hairs on each of the anal lobes near the base of the anal prolegs, as shown in fig. 6, ¢. On July 6 another lot of eggs was placed in each of the two different vessels. One lot was kept moist and the other dry, and both lots were provided with nothing but the particles of dried blood and a few erumbs of dry bread. On July 8 it was discovered that all of the eggs had hatched. Both vessels had been kept closed under a glass cover. Those between the layers of damp blotting paper had apparently not fed. Some were dead, having crawled up the sides of the vessel. Those in the dry receptable were very lively and had fed abundantly, so that the whole alimentary canal, from one end to the other, was dark brown. Fic. 6.—Pulex serraticeps: a, larva; b, head; c, anal end of same—greatly enlarged (original). On July 9 the larve in the dry receptacle had cast the first skin, but upon careful examination were seen to agree perfectly with those of the first stage, except that they were larger. No trace of eyes could be found in either stage. The mandibles apparently bore four blunt teeth. At this date the larve kept in the moist receptacle had not cast a Skin, and appeared almost colorless, having fed very little. In both vessels, however, all the larve were very active and ran about very briskly. Their movements when crawling recall those of many Tineid larve. Ten individuals of the second stage were removed to another vessel to see whether they would cast a second skin. . On July 10 all of the larve in the original moist vessel died. Those in the dry vessel, which had been fed with bread crumbs, were still growing nicely, and were very active. By July 15 all the larve which had been transferred, to watch for further molts, had died without 28 PRINCIPAL HOUSEHOLD INSECTS. molting. They either stuck to the crumbs, which were rather greasy, or to the sides of the glass, which had also become somewhat greasy. On the same date the larvee in the dry vessel, from which these ten had been removed, commenced to spin up. Many were restlessly run- ning about in search of suitable places for spinning, and some had even reached the top of the blotting paper. A thin layer of gray cotton was placed between the two blotting papers to give them suitable spinning places. The eggs hatched in two days, having been kept dry all the time. The first skin was cast two days after hatching, and the beginning of spinning occurred eight days after hatching. By July 19 no more specimens had spun up and many had died. The receptacle seemed to be too dry and too hot, and the blotting paper was somewhat moistened. But one pupa was found, which was that of a larva which began to spin July 15. July 21 no others had spun up, although they were still very lively. The pupa had become brownish. July 22 the adult flea issued over night and escaped through the cov- ering. From that time until July 29 no more spun cocoons, and many of them died. On July 30 one of the survivors commenced to spin, twenty-four days after hatching. The cocoon is delicate, white in color, and is very well shown at fig. 5. On August 2 this larva, which commenced to spin July 21, changed to pupa. On August 6 it was still white in color, becoming somewhat yellowish on the 7th and quite brown on the 8th. On the 9th the adult flea was found to have issued overnight. The pupa state, therefore, lasted about eight days, and it is to be noted that the pupa remains white until shortly before the emergence of the adult. It was supposed that the pupa stage in this instance was longer than usual, on account of the fact that the larval stage was so soy much longer than in the first instance. On July 11 another series of Su veemnente § was started, in order to gauge the variation in the duration of the stages and settle the ques- tion of the number of larval molts. Eggs collected on this date hatched July 13. On July 16, of fifteen larvee eleven had cast the first skin. On July 18 five specimens cast the second skin. July 19 the weather was extremely warm and a number of the larve died. July 20 the heat continued, and more died. On July 23 seven larve which had east the first skin remained; one of them had begun to spin up. There were on the morning of this date three cast skins in the receptacle, so that there are apparently three molts. In this final state the bristles have become longer and the mandibles have two teeth at the apex. The remaining four were carried on until August 8, when the last one died, none. of them having succeeded in casting a third skin. Of the entire lot, but one was reared to the pupa state, and this pupa was preserved in alcohol for drawing. The record of this advanced speci- men shows three molts, and that it began to spin eight days after hatching. The average of the others shows that the eggs hatch in MOSQUITOES AND FLEAS. 29 from two to four days and that some of the larve cast their first skin three to four days later, and a second skin two to six days later. On July 15 another series was begun. The eggs collected on this date began to hatch on the 17th and all had hatched by the morning of the 18th. July 21 some of them had cast the first skin. August 1 the first one spun up; August 3, two more; August 6, two more. At this date the first one which constructed its cocoon turned brown. August 7 one full-grown larva transformed to pupa without spinning a cocoon. August 12 the first adult emerged. A summary for this lot shows that the eggs hatch in from two to four days and that the Jarve cast the first skin from five to seven days later. Some spun up sixteen to twenty days after hatching, and the imago appeared six days later. Observation of these last two lots shows that the larve are very apt to die if kept too dry or too moist. They also need plenty of air. July 20 another series was begun. Eggs collected on this date hatched the following day. July 24 the first skin was cast; July 26, in one case a second skin was cast. July 27 three more cast a second skin, and on this date one individual spun its cocoon. July 29 three more began to spin; on July 30 many more. On July 30 the first one that began to spin was found to have changed to pupa. August 2 many cocoons were found. Some of the larve, disturbed while spin- ning, left the incomplete cocoon and transformed to pupa outside of it. Most of the advanced specimens were placed in alcohol, and it was not until August 14 that an adult was allowed to emerge. This series of observations showed that the eggs hatched about one day after being placed in the vessels. The larvee cast their first skin in from three to seven days, and their second skin in from three to four days. They commenced spinning in from seven to fourteen days after hatching, and the imago appeared five days later. From these observations it appears that in summer at Washington many specimens will undergo their transformations quite as rapidly as Mr. Simmons found to be the case at Calcutta, and that an entire gen- eration may develop in little more than a fortnight; also that an excess of moisture is prejudicial to the successful development of the insect and that in the same way the breeding place must not be too dry. The little particles of blood found among the eggs on the cloth upon which the infested animal has slept are probably the excrement of the aduit fleas. This substance in itself, together with what vegetable dust is found in the places where these larvee rear themselves, suffices for the larval food. . REMEDIES. Flea larve will not develop successfully in situations where they are likely to be disturbed. That they will develop in the dust in the cracks in floors which are not frequently swept has been observed by the writer. The overrunning of houses in summer during the temporary 30 PRINCIPAL HOUSEHOLD INSECTS. absence of the occupants is undoubtedly due to the development of a brood of fleas in the dust in the cracks of the floor from eggs which have been dropped by some pet dog or cat. This overrunning is more liable to occur in moist than in excessively dry summer weather, and it is more likely to occur during the absence of the occupants of the house, for the reason that the floors do not, under such cirecum- stances, receive their customary sweeping. The use of carpets or straw mnattings, in our opinion, favors their development under the cir- cumstances above mentioned. The young larve are so slender and so active that they readily penetrate the interstices of both sorts of cover- ings and find an abiding place in some crack where they are not likely to be disturbed. That it is not difficult to destroy this flea in its early stages is shown by the difficulty we have had in rearing it; but to destroy the adult fleas is another matter. Their extreme activity and great hardiness render any but the most strenuous measures unsuccessful. In such cases we have tried a number of the ordinarily recommended remedies in vain. Even the persistent use of California buhach and other pyrethrum powders, and, what seems still stranger, a free sprinkling of floor mat- ting with benzine, were ineffectual in one particular case of extreme infestation. In fact, it was not until all the floor mattings had been taken up and the floor washed down with hot soapsuds that the flea pest abated. In another case, however, the writer found that a single application of California buhach, freely applied, was perfectly success- ful; and in a third case a single thorough application of benzine also resulted in perfect success. The pyrethrum application was made in a Brooklyn (N. Y.) house, and the benzine application in a Washington residence. The frequently recommended newspaper remedy of placing a piece of raw meat in the center of a piece of sticky fly paper has been thoroughly tried by the writer, without the slightest success. As a palliative measure, however, the plan adopted by Professor Gage in the McGraw Building of Cornell University, and described at length on page 422 of Vol. VII, Insect Life, may be worth trying. It will be remembered that Professor Gage tied sheets of sticky fly paper, with the sticky side out, around the legs of the janitor of the building, who then for several hours walked up and down the floor of the infested room, with the result that all or nearly all of the fleas jumped on his ankles, as they will always do, and were caught by the fly paper. In his recent summary of the described fleas (Canadian Entomolo- gist, August, 1895, pp. 221-222) Mr. C. F. Baker shows that there are forty-seven valid species, which attack all sorts of warm-blooded animals. The species which we have just considered (Pulex serrati- ceps Gervais) is, as he states, the common cat and dog flea, well known over all parts of the world. Mr. Baker further states that, ‘‘besides the various wild cats and dogs, it has been reported from Herpestes ichneumon (Pharaoh’s rat), Fetorius putorius (common polecat of MOSQUITOES AND FLEAS. 31 Europe), Hyena striata (striped hyena), Lepus timidus (common hare), and Procyon lotor (raccoon). It is also said to occasionally sip human blood [ste /]. I have specimens from various parts of North America, and also from Europe.” Many unfortunate inhabitants of New York, Philadelphia, Washington, and Baltimore during the past few summers will be able to verify Mr. Baker’s statement that the species ocea- sionally sips human blood! This species may be distinguished at a glance from the so-called human flea (Pulex irritans) by the fact that the latter species does not possess the strong recurved spines on the margin of the head, which show so distinctly in fig. 5. CHAPTER II. THE BEDBUG AND CONE-NOSE. By C. L. MAR.LaTT. THE BEDBUG. (Cimex lectularius Linn.) This disgusting hitman parasite, the very discussion of which is tabooed in polite society, is practically limited to houses of the meaner sort, or where the owners are indifferent or careless, or to hostelries not always of the cheaper kind. The careful housekeeper would feel it a signal disgrace to have her chambers invaded by this insect, and, in point of fact, where ordinary care and vigilance are maintained the danger in this direction is very slight. The presence of this insect, however, is not necessarily an indication of neglect or carelessness, for, Fic. 7.—Cimez lectularius: a, adult female, gorged with blood; b, same, from below; ¢, rudimentary wing-pad; d, mouth-parts—all enlarged (original). © little as the idea may be relished, it may often gain access in spite of the best of care and the adoption of all reasonable precautions. Itis very apt to get into the trunks and satchels of travelers, and may thus be introduced into homes. Unfortunately, also, it is quite capable of | migrating from one house to another, and will often continue to come from an adjoining house, sometimes for a period of several months, gaining entrance daily. Such migration is especially apt to take place if the human inhabitants of an infested house leave it. With the 32 THE BEDBUG AND CONE-NOSE. aa failure of their usual source of food, the migratory instinet is devel- oped, and escaping through windows, they pass along walls, water pipes, or gutters, and thus gain entrance into adjoining houses. It is expe- dient, therefore, to consider this insect, unsavory as the subject may be, since, as shown, it may be anyone’s misfortune to have his premises temporarily invaded. As with nearly all the insects associated with man, the bedbug has had the habits now characteristic of it as far back as the records run. It was undoubtedly of common occurrence in the dwellings of the ancient peoples of Asia. The Romans were well acquainted with it, giv- ing it the name Cimex. It was supposed by Pliny (and this was doubt- less the common belief among the Romans) to have medicinal properties, and it was recommended, among other things, as a specific for the bites of serpents. It is said to have been first introduced into England in 1503, but the references to it are of such a nature as to make it very probable that it had been there long previously. Two hundred and fifty Fie. 8.— Cimex lectularius. Egg and newly hatched larva of bedbug: a, larva from below; b, larva | from above; ¢, claw; d, egg; e, hair or spine of larva—greatly enlarged; natural size of larva and egg indicated by hair lines (original). years later it was reported to be very abundant in the seaport towns, but was scarcely known inland. It has been inferred that the following reference from the old English Bible of 1551 is to this insect: “Thou shalt not nede to be afriad for eny Bugges by night” (Psalm XCTI, 5). One of the old English names was “wall-louse.” It was afterwards very well known as the ‘“chinch,” which continued to be the common appellation for it until within a century or two, and is still used in parts of this country. The origin of the name “bedbug” is not known, but it is such a descriptive one that it would seem to have been very natu- rally suggested. Almost everywhere there are local names for this parasite, as, for illustration, around Boston they are called ‘“‘chintzes” and ‘‘chinches,” and from Baltimore comes the name ‘mahogany flat,” while in New York they are styled ‘‘red coats.” The bedbug has accompanied man wherever he has gone. Vessels are almost sure to be infested with it. It is not especially limited by cold, and is known to occur well north. It probably came to this 2805—No. 4 3 34 PRINCIPAL HOUSEHOLD INSECTS. country with the earliest colonists, at least Kalm, writing in 1748-49, stated that it was plentiful in the English colonies and in Canada, though unknown among the Indians. The bedbug belongs to the order Hemiptera, which includes the true bugs or piercing insects, characterized by possessing a piercing and sucking beak. The bedbug is to man what the chinch bug is to grains or the squash bug to cucurbs. Like nearly all the insects parasitic on animals, however, it is degraded structurally, its parasitic nature aud the slight necessity for extensive locomotion having resulted, after many ages doubtless, in the loss of wings and the assumption of a comparatively simple structure. The wings are represented by the merest rudiments, barely recognizable pads, and it lacks the simple eyes or ocelli of most other true bugs. In form it is much flattened, obovate, and in color is rust red, with the abdomen more or less tinged with black. The absence of wings is a most fortunate circumstance, since otherwise thcre would be no safety from it even for the most careful and thorough of housekeepers. Some slight variation in length of wing pads has been observed, but none with wings showing any considerable development have ever been found. A closely allied species is a parasitic messmate in the nests of the common barn or eaves swallow in this country, and it often happens that the nests of these birds are fairly alive with these vermin. The latter not infrequently gain access to houses, and cause the housekeeper con- siderable momentary alarm. At least three species occur also in Eng- land, all very closely resembling the bedbug. One of these is found in pigeon cotes, another in the nests of the English martin, and a third in places frequented by bats. What seems to be the true bedbug, or at least a mere variety, also occurs occasionally in poultry houses.! The most characteristic feature of the insect is the very distinct and disagreeable odor which it exhales, an odor well known to all who have been familiar with it as the ‘‘buggy” odor. This odor is by no means limited to the bedbug, but is characteristic of most plant bugs also. The common chinch bug affecting small grains and the squash bugs all possess this odor, and it is quite as pungent with these plant-feeding forms as with the human parasite. The possession of this odor, dis- agreeable as it is, 1s, after all, a most fortunate circumstance, as it is of considerable assistance in detecting the presence of these vermin. The odor comes from glands, situated in various parts of the body, which secrete a clear, oily, volatile liquid. The possession of this odor is cer- tainly, with the plant-feeding forms, a means of protection against insectivorous birds, rendering these insects obnoxious or distasteful to their feathered enemies. With the bedbug it is probably an illustration of a very common phenomenon among animals, the persistence of a characteristic which is no longer of any especial value to the possessor of it. The natural enemies of true bugs, against which this odor serves ‘Insect Life, Vol, VI, p. 166, Osborn. THE BEDBUG AND CONE-NOSE. 35 as a means of protection, in the conditions under which the bedbug lives, are kept away from it, and the roach, which will be shown later to feed on bedbugs, is evidently not deterred by the odor, while the com- mon house ant, which will also attack the bedbug, seems not to find this odor disagreeable. The bedbug is thoroughly nocturnal in habit and displays a certain degree of wariness and caution, or intelligence, in its efforts at con- cealment during the day. It thrives particularly in filthy apartments and in old houses which are full of cracks and crevices in which it can conceal itself beyond easy reach. It usually leaves the bed at the approach of daylight to go into concealment either in cracks in the bedstead, if it be one of the old wooden variety, or behind wainscoting, or under loose wall paper, where it manifests its gregarious habit by col- lecting in masses together. The old-fashioned heavy wooden bedsteads are especially faverable for the concealment and multiplication of this diately after emerging from a; c, same after first meal, distended with blood (original). insect, and the general use in later years of iron and brass bedsteads has very greatly facilitated its eradication. They are not apt to be very active in winter, especially in cold rooms, and ordinarily hibernate in their places of concealment. The bedbug, though normally feeding on human blood, seems to be abie to subsist for a time at Jeast on much simpler food, and in fact the evidence is pretty conclusive that itis able to get more or less suste- nance from the juices of moistened wood, or the moisture in the accu- mulations of dust, ete., in crevices in flooring. No other explanation would seem to account for the fact that houses long unoccupied are found, on being reinhabitated, to be thoroughly stocked with bedbugs. There is a very prevalent belief among the old settlers in the West that this insect normally lives on dead or diseased cottonwood logs, and is almost certain to be abundant in log houses of this wood. This belief was recently voiced by Capt. S. M. Swigert, U.S. A., who reports that it often occurs in numbers under the bark of dead trees of cotton- 36 PRINCIPAL HOUSEHOLD INSECTS. wood (Populus monilifera), especially along the Big and Little Horn rivers in Montana. The origin of this misconception—for such it is—so far as the out-of- door occurrence is concerned, is probably, as pointed out by Professor Riley, from a confusion of the bedbug with the immature stages of an entirely distinct insect (Aradus sp.) which somewhat resembles the former and often occurs under cottonwood bark. In houses, green or moist cottonwood logs or lumber may actually furnish sustenance in the absence of human food. The bedbug is, however, known to be able to survive for long periods without food, specimens having been kept for a year in a sealed vial, with absolutely no means of sustenance whatever, and in unoccupied houses it can undoubtedly undergo fasts of extreme length. Individuals obtained from eggs have been kept in small sealed vials in this office for several months, remaining active and sprightly in spite of the fact that they had never taken any nour- ishment whatever. Extraordinary stories are current of the remarkable intelligence of this insect in circumventing various efforts to prevent its gaining access to beds. Most of these are undoubtedly exaggerations, but the inher- ited experience of many centuries of companionship with man, during which the bedbug has always found its host an active enemy, has resulted in a knowledge of the habits of the human animal and a facil- ity of concealment, particularly as evidenced by its abandoning beds and going often to distant quarters for protection and hiding during daylight, which indicate considerable apparent inteliigence. The bite of the bedbug is decidedly poisonous to some individuals, resulting in a slight swelling and disagreeable inflammation. To such persons the presence of bedbugs is sufficient to cause the greatest uneasiness, if not to put sleep and rest entirely out of the question. With others, however, who are less sensitive, the presence of the bugs may not be recognized at all, and, except for the occasional staining of the linen by a crushed individual, their presence might be entirely overlooked. The inflammation experienced by sensitive persons seems to result merely from the puncture of the skin by the sharp piercing sete which constitute the puncturing element of the mouth parts, as there seems to be no secretion of poison other than the natural fluids of the mouth. The biting organ of the bedbug is exactly like that of other hemip- terous insects. It consists of a rather heavy, fleshy under lip (the only part ordinarily seen in examining the insect), within which lie four thread-like hard filaments or sete which glide over each other with an alternating motion and pierce the flesh. The blood is drawn up through the beak, which is closely applied to the point of puncture, and the alternating motion of these setz in the flesh causes the biood to flow more freely. The details of the structure of the beak areshown in the accompanying sketch (fig. 7, d). Jn common with other insects THE BEDBUG AND CONE-NOSE. ah (L which attack men. it is entirely possible for these pests to be transmit- ters of contagious diseases. Like its allies, the bedbug undergoes an incomplete metamorphosis, the young being very similar to their parents in appearance, structure, and in habit. The eggs are white oval objects, having a little project- ing rim around one edge, and are laid in batches of from one-half dozen to fifty in cracks and crevices where the bugs go for concealment. The egos hatch in a week or ten days, and the young escape by pushing the lid within the projecting rim from the shell. At first they are yel- lowish white, nearly transparent, the brown color of the more mature insect inereasing with the later molts. During the course of develop- ment the skin is shed five times, and with the last molt the minute wing pads characteristic of the adult insect make their appearance. A period of about eleven weeks has been supposed to be necessary for the complete maturity of this insect, but we have found this period subject to great variation, depending on warmth and food supply. Breeding experiments conducted at this office indicate, under most favorable conditions, a period averaging eight days between moltings and between the laying of the eggs and their hatching, giving about seven weeks as the period from egg to adult insect. Some individuals under the same conditions will, however, remain two to three weeks between moltings, and without food as already shown they may remain unchanged for an indefinite time. Ordinarily but one meal is taken between molts, so that each bedbug must puncture its host five times before becoming mature and at least once afterwards before it again develops eggs. They are said to lay several batches of eggs during the season, and are extremely prolific, as occasionally realized by the housekeeper, to her chagrin and embarrassment. REMEDIES. The bedbug, on account of its habits of concealment, is usually beyond the reach of powders, and the ordinary insect powders, such as pyrethrum, are of practically no avail against it. If iron or brass bedsteads are used the eradication of the insect is comparatively easy. With large wooden bedsteads, furnishing many cracks and crevices into which the bugs can force their flat, thin bodies, their extermina- tion becomes a matter of considerable difficulty. The most practical way to effect this end is by very liberal applications of benzine or kerosene or any other of the petroleum oils. These must be introduced into all crevices with small brushes or feathers, or by injecting with small syringes. Corrosive sublimate is also of value, and oil of tur- pentine may be used in the same way. The liberal use of hot water wherever if may be employed without danger to furniture, etc., is also an effectual method of destroying both eggs and active bugs. Various bedbug remedies and mixtures are for sale, most of them containing one or the other of the ingredients mentioned, and they are frequently 38 PRINCIPAL HOUSEHOLD INSECTS, of value. The great desideratum, however, in a case of this kind, is 4 daily inspection of beds and bedding and of all crevices and locations about the premises where these vermin may have gone for conceal- ment. TS PN Bs N experiments were made in as! ioe} Yas 7X this office during the summer of 1895, and it was unexpect- edly found that the house fly is a difficult insect to rear in confinement. Buzzing about everywhere, and apparently living with ease under the most adverse conditions, itis nevertheless, when confined in the warm season of the year to a small receptacle, not at all tenacious of life. It results from this fact, for example, that it is almost a impossible to ascertain the ~ 4 ee length of the life of the house OO fly in the adult condition. Fic. 14._Musca domestica: a, full-grown larva; b, one of On June 26a small quantity its anterior spiracles; c, side view of head; d, hind end of fresh horse manure was of body showing anal spiracles; e, side view of head; - ais f, head from above; g, head of young larva from above; exposed lh afly-infested room h, eggs—all enlarged (original). for a few minutes. The flies deposited their eggs freely and immediately in this substance.! At the same time the specimens were confined in,a glass dish 7.5 inches in diam- eterand 3 inchesin height. In this dish was a layer of moist sand, cov- ered with a layer of fresh horse manure, and the vessel was covered with a piece of gauze. On the following morning all the flies, twenty-four in number, were dead, and not a single egg had been laid. A fresh sup- ply of flies was introduced into the same vessel, and the next morning all were dead and no eggs had been laid. The cover was now removed from this vessel and the latter placed in a glass cylinder 14 inches high, the 1The experiments which follow were conducted by Mr. D. W. Coquillett. 46 PRINCIPAL HOUSEHOLD INSECTS. top of which was covered with gauze, and twenty flies introduced. This was at noon; by 4 o’clock in the afternoon no eggs could be found, but at 9 o’clock the next morning two clusters of eggshells, one cluster containing 26 and the other 45 eggs, were found. The eggs had been deposited in small cavities between the sides of the vessel and the manure, at a depth of about a quarter of an inch below the surface, but were not arranged in any regular order. Afterwards several black- berries, cherries, and partly decayed apples were placed in this vessel, and more fhes were introduced.