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diff --git a/59554-0.txt b/59554-0.txt new file mode 100644 index 0000000..0ac1965 --- /dev/null +++ b/59554-0.txt @@ -0,0 +1,607 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 59554 *** + + + + + + + + + + + + +Transcriber Notes + +Text emphasis displayed as _Italics_ and =Bold=. + + + + + Issued July 31, 1911. + + U. S. DEPARTMENT OF AGRICULTURE. + + + + FARMERS' BULLETIN 459. + + + + HOUSE FLIES. + + + + BY + + L. O. HOWARD, + _Chief of the Bureau of Entomology_. + + + [Illustration] + + + WASHINGTON: + GOVERNMENT PRINTING OFFICE. + 1911. + + + + + LETTER OF TRANSMITTAL + + + U. S. Department of Agriculture, + Bureau of Entomology, + _Washington, D. C, May 23, 1911_. + +Sir: I have the honor to transmit for publication a paper dealing with +the subject of the house fly or typhoid fly. Previous publications of +this department concerning this insect have been in circular form, but +it is desired to make this information more widely available through +the medium of a Farmers' Bulletin. With this intention this manuscript +has been prepared, being modified and amplified from Circular No. 71 of +this bureau, and I respectfully recommend its publication as a Farmers' +Bulletin. + + Respectfully, + + L. O. Howard, + _Entomologist and Chief of Bureau_. + + Hon. James Wilson, + _Secretary of Agriculture_. + + +[A list giving the titles of all Farmers' Bulletins available for +distribution will be sent free upon application to a Member of Congress +or the Secretary of Agriculture.] + + + + +CONTENTS. + + + Page. + + Introduction 5 + + Life history of the true house fly 7 + + Carriage of disease 9 + + Remedies and preventives 10 + + Natural enemies 15 + + What cities and towns can do 15 + + + + +ILLUSTRATIONS. + + + Page. + + 1. The common house fly (_Musca domestica_); Puparium, + adult, larva, and details 5 + + 2. The biting house fly (_Stomoxys calcitrans_): Adult, + larva, puparium, and details 6 + + 3. A stable fly (_Muscina stabulans_): Adult, larva, + and details 7 + + 4. One of the blue-bottle flies (_Phormia terrænovæ_): Adult 8 + + 5. The green-bottle fly (_Lucilia cæsar_): Adult 8 + + 6. The little house fly (_Homalomyia brevis_): Adults and larva 9 + + 7. The fruit fly (_Drosophila ampelophila_): Adult, larva, + puparium, and details. 10 + + 8. The dung fly (_Sepsis violacea_): Adult, puparium, and + details 11 + + 9. The house centipede (_Scutigera forceps_): Adult 14 + + + + +HOUSE FLIES. + + + +INTRODUCTION. + + +There are several species of flies which are commonly found in houses, +although but one of these should be called the house fly proper. This +is the _Musca domestica_ L. (fig. 1 ) and is a medium-sized, grayish +fly, with its mouth parts spread out at the tip for sucking up liquid +substances. It is found in nearly all parts of the world. On account +of the conformation of its mouth parts, the house fly can not bite, +yet no impression is stronger in the minds of most people than that +this insect does occasionally bite. This impression is due to the +frequent occurrence in houses of another fly (_Stomoxys calcitrans_ +L.) (fig. 2), which is called the stable fly, and which, while closely +resembling the house fly (so closely, in fact, as to deceive anyone +but an entomologist), differs from it in the important particular +that its mouth parts are formed for piercing the skin. It is perhaps +second in point of abundance to the house fly in most portions of the +Northeastern States. It breeds in horse manure, cow manure, and in warm +decaying vegetation like old straw and grass heaps. + +[Illustration: Fig. 1.--The common house fly (_Musca domestica_): +Puparium at left; adult next; larva and enlarged parts at right. All +enlarged. (Author's Illustration.)] + +A third species, commonly called the cluster fly (_Pollenia rudis_ +Fab.), is a very frequent visitant of houses, particularly in the +spring and fall. This fly is somewhat larger than the house fly, with a +dark-colored, smooth abdomen and a sprinkling of yellowish hairs. It is +not so active as the house fly and, particularly in the fall, is very +sluggish. At such times it may be picked up readily and is very subject +to the attacks of a fungous disease which causes it to die upon window +panes, surrounded by a whitish efflorescence. Occasionally this fly +occurs in houses in such numbers as to cause great annoyance, but such +occurrences are comparatively rare. It is said in its earlier stages to +be parasitic on certain angleworms. + +A fourth species is another stable fly, known as _Muscina stabulans_ +Fall. (fig. 3), a form which almost exactly resembles the house fly in +general appearance, and which does not bite as does the biting stable +fly. It breeds in decaying vegetable matter and in excrement. + +[Illustration: Fig. 2.--The stable fly or biting house fly (_Stomoxys +calcitrans_): Adult, larva, puparium, and details. All enlarged. +(Author's illustration.)] + +Several species of metallic greenish or bluish flies are also +occasionally found in houses, the most abundant of which is the +so-called blue-bottle fly (_Calliphora erythrocephala_ Meig.). This +insect is also called the blow-fly or meat-fly and breeds in decaying +animal material. A smaller species, which may be called the small +blue-bottle fly, is _Phormia terrænovæ_ Desv. (fig. 4); and a third, +which is green or blue in color and a trifle smaller than the large +blue-bottle, is _Lucilia cæsar_ L. (fig. 5). + +There is still another species, smaller than any of those so far +mentioned, which is known to entomologists as _Homalomyia canicularis_ +L., sometimes called the small house fly. A related species, _H. +brevis_ Rond., is shown in figure 6. _H. canicularis_ is distinguished +from the ordinary house fly by its paler and more pointed body and +conical shape. The male, which is much commoner than 'the female, has +large pale patches at the base of the abdomen, which are translucent +when the fly is seen on a window pane. It is this species that is +largely responsible for the prevalent idea that flies grow after +gaining wings. Most people think that these little Homalomyias are +the young of the larger flies, which, of course, is distinctly not +the case. They breed in decaying vegetable material, in the excreta of +animals, and in dead insects. + +Still another fly, and this one is still smaller, is a jet-black +species known as the window fly (_Scenopinus fenestralis_ L.), which +in fact has become more abundant of later years. Its larva is a white, +very slender, almost thread-like creature, and is found in cracks of +the floor in buildings, where it feeds on other small insects. + +In the autumn, when fruit appears on the sideboard, many specimens of +a small fruit-fly (_Drosophila ampelophila_ Loew) (fig. 7) make their +appearance, attracted by the odor of overripe fruit. + +A small, slender fly is not infrequently seen in houses, especially +upon window panes. This is _Sepsis violacea_ Meig., shown enlarged in +figure 8. + +[Illustration: Fig. 3.--A stable fly (_Muscina stabulans_): Adult, +larva, and details. All enlarged. (Author's Illustration.)] + +All of these species, however, are greatly dwarfed in numbers by the +common house fly. In 1900 the writer made collections of the flies in +dining rooms in different parts of the country, and out of a total of +23,087 flies 22,808 were _Musca domestica_--that is, 98.8 per cent of +the whole number captured. The remainder, consisting of 1.2 per cent of +the whole, comprised various species, including those mentioned above. + + +LIFE HISTORY OF THE TRUE HOUSE FLY. + +_Musca domestica_ commonly lays its eggs upon horse manure. This +substance seems to be its favorite larval food. It will oviposit on +cow manure, but we have not been able to rear it in this substance. +It will also breed in human excrement, and from this habit it becomes +very dangerous to the health of human beings, carrying, as it does, +the germs of intestinal diseases such as typhoid fever and cholera from +excreta to food supplies. It will also lay its eggs upon other decaying +vegetable and animal material, but of the flies that infest dwelling +houses, both in cities and on farms, a vast proportion comes from horse +manure. + +[Illustration: Fig. 4.--One of the blue-bottle flies (_Phormia +terrænovæ_): Adult, enlarged. ( Author's Illustration.)] + +It often happens, however, that this fly is very abundant in localities +where there is little or no horse manure, and in such cases it will +be found breeding in other manure or in slops or fermenting vegetable +material, such as spent hops, or bran, or ensilage. + +At Salem, Mass., Packard states that he reared a generation in 14 +days in horse manure. The duration of the egg state was 24 hours, the +larval state from 5 to 7 days, and the pupal state from 5 to 7 days. +At Washington the writer has found in midsummer that each female lays +at one time about 120 eggs, which hatch in 8 hours, the larval period +lasting 5 days and the pupal 5 days, making the total time for the +development of the generation 10 days. This was at the end of June. The +periods of development vary with the climate and with the season, and +the insect hibernates in the puparium condition in manure or at the +surface of the ground under a manure heap. It also hibernates in houses +as adult, hiding in crevices. + +The Washington observations indicate that the larvæ molt twice, and +that there are thus three distinct larval stages. + +The periods of development were found to be about as follows: Egg +from deposition to hatching, one-third of a day; hatching of larva +to first molt, 1 day; first to second molt, 1 day; second molt to +pupation, 3 days; pupation to issuing of adult, 5 days; total life +round, approximately 10 days. There is thus abundance of time for the +development of 12 or 13 generations in the climate of Washington every +summer. + +[Illustration: Fig. 5.--The green-bottle fly (_Lucilia cæsar_): Adult, +enlarged. (Author's Illustration.)] + +The number of eggs laid by an individual fly at one time is undoubtedly +large, averaging about 120, and a single female may lay 4 such batches, +so that the enormous numbers in which the insects occur is thus plainly +accounted for, especially when the abundance and universal occurrence +of appropriate larval food is considered. In order to ascertain the +numbers in which house-fly larvæ occur in horse-manure piles, a quarter +of a pound of rather well-infested horse manure was taken on August 9, +and in it were counted 160 larvæ and 146 puparia. This would make about +1,200 house flies to the pound of manure. This, however, can not be +taken as an average, since no larvæ are found in perhaps the greater +part of ordinary horse-manure piles. Neither, however, does it show +the limit of what can be found, since about 200 puparia were found in +less than 1 cubic inch of manure taken from a spot 2 inches below the +surface of the pile where the larvæ had congregated in immense numbers. +The different stages of the insect are well illustrated in figure 1 and +need no description. + +[Illustration: Fig. 6.--The little house fly (_Homalomyia brevis_): +Female at left; male next, with enlarged antenna; larva at right. All +enlarged. (Author's Illustration.)] + + +CARRIAGE OF DISEASE. + +In army camps, in mining camps, and in great public works, bringing +together large numbers of men for a longer or shorter time, there is +seldom the proper care of excreta, and the carriage of typhoid germs +from the latrines and privies to food by flies is common and often +results in epidemics of typhoid fever. + +And such carriage of typhoid by flies is by no means confined to these +great temporary camps. In farmhouses in small communities and even +in the badly cared-for portions of large cities typhoid germs are +carried from excrement to food by flies, and the proper supervision and +treatment of the breeding places of the house fly become most important +elements in the prevention of typhoid. + +In the same way other intestinal germ diseases are carried by flies. +The Asiatic cholera, dysentery, and infantile diarrhea are all so +carried. + +Nor are the disease-bearing possibilities of the house fly limited to +intestinal germ diseases. There is strong circumstantial evidence that +tuberculosis, anthrax, yaws, ophthalmia, smallpox, tropical sore, and +parasitic worms may be and are so carried. Actual laboratory proof +exists in the cases of a number of these diseases, and where lacking is +replaced by circumstantial evidence amounting almost to certainty. + + +REMEDIES AND PREVENTIVES. + +A careful screening of windows and doors during the summer months, with +the supplementary use of sticky fly papers, is a preventive measure +against house flies known to everyone, and there seems to be little +hope in the near future of much relief by doing away with the breeding +places. A single stable in which a horse is kept will supply house +flies for an extended neighborhood. People living in agricultural +communities will probably never be rid of the pest, but in cities, +with better methods of disposal of garbage and with the lessening of +the number of horses and horse stables consequent upon electric street +railways, bicycles, and automobiles, the time may come, and before +very long, when window screens may be discarded. The prompt gathering +of horse manure, which may be variously treated or kept in a specially +prepared receptacle, would greatly abate the fly nuisance, and city +ordinances compelling horse owners to follow some such course are +desirable. Absolute cleanliness, even under existing circumstances, +will always result in a diminution of the numbers of the house fly, +and, in fact, most household insects are less attracted to the premises +of what is known as the old-fashioned house-keeper than to those of the +other kind. + +[Illustration: Fig. 7.--The fruit fly (_Drosophila ampelophila_): _a_, +Adult; _b_, antenna of same; _c_, base of tibia and first tarsal joint +of same; _d_, puparium, side view; _e_, puparium from above; _f_, +full-grown larva; _g_, anal spiracles of same. All enlarged. (Author's +illustration.)] + +Not only must all horse stables be cared for, but chicken yards, +piggeries, and garbage receptacles as well, and absolutely sanitary +privies are prime necessities. Directions for building and caring for +such privies will be found in Farmers' Bulletin No. 463. The dry-earth +treatment of privy vaults is unsatisfactory. Kerosene should be used. + +[Illustration: Fig. 8.--The dung fly (_Sepsis violacea_): Adult, +puparium, and details. All enlarged. (Author's illustration.)] + +During the summer of 1897 a series of experiments was carried out +with the intention of showing whether it would be possible to treat +a manure pile in such a way as to stop the breeding of flies. The +writer's experience with the use of air-slaked lime on cow manure to +prevent the breeding of the horn fly (_Hæmatobia serrata_ Rob.-Desv.) +suggested experimentation with different lime compounds. It was found +to be perfectly impracticable to use air-slaked lime, land plaster, or +gas lime with good results. Few or no larvæ were killed by a thorough +mixing of the manure with any of these three substances. Chlorid of +lime, however, was found to be an excellent maggot killer. Where 1 +pound of chlorid of lime was mixed with 8 quarts of horse manure, 90 +per cent of the maggots were killed in less than 24 hours. At the rate +of one-fourth of a pound of chlorid of lime to 8 quarts of manure, +however, the substance was found not to be sufficiently strong. Chlorid +of lime, though cheap in Europe, costs at least 3-1/2 cents a pound in +large quantities in this country, so that the frequent treatment of a +large manure pile with this substance would be out of the question in +actual practice. + +Experiments were therefore carried on with kerosene. It was found that +8 quarts of fresh horse manure sprayed with 1 pint of kerosene, which +was afterwards washed down with 1 quart of water, was thoroughly rid +of Irving maggots. Every individual was killed by the treatment. This +experiment and others of a similar nature on a small scale were so +satisfactory that it was considered at the close of the season that +a practical conclusion had been reached, and that it was perfectly +possible to treat any manure pile economically and in such a way as to +prevent the breeding of flies. + +Practical work in the summer of 1898, however, demonstrated that this +was simply another case where an experiment on a small scale has failed +to develop points which in practical work would vitiate the results. + +The stable of the United States Department of Agriculture, in which +about 12 horses were kept, was situated about 100 yards behind the +main building of the department and about 90 yards from the building +in which the Bureau of Entomology is situated. This stable was always +very carefully kept. The manure was thoroughly swept up every morning, +carried outside of the stable, and deposited in a pile behind the +building. This pile, after accumulating for a week or 10 days, or +sometimes 2 weeks, was carried off by the gardeners and spread upon +distant portions of the grounds. At all times in the summer this manure +pile swarmed with the maggots of the house fly. It is safe to say that +on an average many thousands of perfect flies issued from it every day, +and that at least a large share of the flies which constantly bothered +the employees in the two buildings mentioned came from this source. + +On the basis of the experiments of 1897, an attempt was made, beginning +early in April, 1898, to prevent the breeding of house flies about the +department by the treatment of this manure pile with kerosene. The +attempt was begun early in April and was carried on for some weeks. +While undoubtedly hundreds of thousands of flies were destroyed in the +course of this work, it was found by the end of May that it was far +from perfect, since if used at an economical rate the kerosene could +not be made to penetrate throughout the whole pile of manure, even +when copiously washed down with water. A considerable proportion of +house-fly larvæ escaped injury from this treatment, which at the same +time was found, even at an economical cost, to be laborious, and such a +measure, in fact, as almost no one could be induced to adopt. + +There remained, however, another measure which had been suggested by +the writer in an article on the house fly published in 1895, namely, +the preparation of an especial receptacle for the manure; and this +was very readily accomplished. A closet 6 by 8 feet had been built +in the corner of the stable nearest the manure pile. It had a door +opening into the stable proper, and also a window. A door was built in +the outside wall of this closet, and the stablemen were directed to +place no more manure outside the building; in other words, to abolish +the outside manure pile, and in the future to throw all of the manure +collected each morning into this closet, the window of which in the +meantime had been furnished with a wire screen. The preparations were +completed by the middle of June, and a barrel of chlorid of lime was +put in the corner of the closet. Since that time every morning the +manure of the stable is thrown into the closet, and a small shovelful +of chlorid of lime is scattered over it. At the expiration of 10 days +or 2 weeks the gardeners open the outside door, shovel the manure into +a cart, and carry if off to be thrown upon the grounds. + +Judging from actual examination of the manure pile, the measure is +eminently successful. Very few flies are breeding in the product of +the stable which formerly gave birth to many thousands daily. After +this measure had been carried on for two weeks, employees of the +department who had no knowledge of the work that was going on were +asked whether they had noticed any diminution in the number of flies in +their offices. Persons in all of the offices on the first floor of the +two buildings were asked this question. In every office except one the +answer was that a marked decrease had been noticed, so that the work +must be considered to have been successful. + +The account of this remedial work has been given with some detail, +since it shows so plainly that care and cleanliness combined with +such an arrangement as that described will in an individual stable +measurably affect the fly nuisance in neighboring buildings. + +With the combined efforts of the persons owning stables in a given +community, much more effective results can undoubtedly be gained. + +In the consideration of these measures we have not touched upon the +remedies for house flies breeding in human excrement. On account of +the danger of the carriage of typhoid fever, the dropping of human +excrement in the open in cities or towns, either on vacant lots or +in dark alleyways, should be made a misdemeanor, and the same care +should be taken by the sanitary authorities to remove or cover up such +depositions as is taken in the removal of the bodies of dead animals. +The box privy is always a nuisance from many points of view, and is +undoubtedly dangerous as a breeder of flies which may carry the germs +of intestinal disease. No box privies should be permitted to exist +unless they are conducted on the kerosene principle. With a proper +vault or other receptacle, closed except from above, and a free use of +kerosene and water, the breeding of house flies can be prevented. + +[Illustration: Fig. 9.--The house centipede (_Scutigera forceps_) Adult +natural size (After Marlatt.)] + +A Parisian journal, the Matin, during the winter of 1905-6, established +a prize of 10,000 francs for the best essay on the destruction of the +house fly. The jury of competent scientific men awarded the prize to +the author of a memoir in which it was proposed to use residuum oil in +the destruction of the eggs and larvæ of the fly. This oil is to be +used in privies and cesspools. Two liters per superficial meter of the +pit is mixed with water, stirred with a stick of wood, and then thrown +into the receptacle. It is said to form a covering of oil which kills +all the larvæ, preventing the entrance of flies into the pit and, at +the same time, the hatching of eggs. It makes a protective covering for +the excrement, and this is said to hasten the development of anærobic +bacteria as in a true septic pit, leading in this way to the rapid +liquefaction of solid matters and rendering them much more unfit for +the development of other bacteria. For manure it is recommended to mix +this residuum oil with earth, with lime, and with phosphates, and to +spread it at different times, in the spring by preference, upon the +manure of farms and stables and so on. + +There seems to be a definite period of perhaps 10 days between the +issuing of the adult flies and the laying of eggs. During this period, +and especially in the early spring, it becomes important to trap as +many flies as possible. With this end in view, Prof. C. F Hodge, of +Clark University, Worcester, Mass., has devised certain flytraps which +he attaches to garbage cans and to screened stable windows, and which +he places in the neighborhood of possible fly-breeding places. + +So many cheap flytraps are on the market that it is unnecessary and +undesirable to specify any particular kind. Many of them are good. + + +NATURAL ENEMIES. + +The house fly has a number of natural enemies. The common house +centipede (fig. 9) destroys it in considerable numbers, there is a +small reddish mite which frequently covers its body and gradually +destroys it, it is subject to the attacks of hymenopterous parasites in +its larval condition, and it is destroyed by predatory beetles at the +same time. + +The most effective enemy, however, is a fungous disease known as +_Empusa muscæ_, which carries off flies in large numbers, particularly +toward the close of the season. The epidemic ceases in December, and +although many thousands are killed by it, the remarkable rapidity of +development in the early summer months soon more than replaces the +thousands thus destroyed. + + +WHAT CITIES AND TOWNS CAN DO. + +It would appear, from what we know of the life history of the common +house fly and from what remedial experimentation has already been +carried on, that it is perfectly feasible for cities and towns +to reduce the numbers of these annoying and dangerous insects so +greatly as to render them of comparatively slight account. The health +departments of most of our cities have the authority to abate nuisances +dangerous to health, and it is easy for the health authorities of any +city to formulate rules concerning the construction and care of stables +and the keeping and disposal of manure which, if enforced, will do away +with the house-fly nuisance. Such a series of rules was formulated in +the spring of 1906 by the Health Department of the city of Asheville, +N. C, and an effort is being made during this summer to see that they +are enforced. On the 3d of May, 1906, the Health Department of the +District of Columbia also issued a series of orders of this nature, on +the authority of the Commissioners of the District, and these orders, +which may well serve as a model to other communities desiring to +undertake similar measures, may be briefly condensed as follows: + +All stalls in which animals are kept shall have the surface of the +ground covered with a water-tight floor. Every person occupying a +building where domestic animals are kept shall maintain, in connection +therewith, a bin or pit for the reception of manure, and, pending the +removal from the premises of the manure from the animal or animals, +shall place such manure in said bin or pit. This bin shall be so +constructed as to exclude rain water, and shall in all other respects +be water tight except as it may be connected with the public sewer. +It shall be provided with a suitable cover and constructed so as to +prevent the ingress and egress of flies. No person owning a stable +shall keep any manure or permit any manure to be kept in or upon any +portion of the premises other than the bin or pit described, nor shall +he allow any such bin or pit to be overfilled or needlessly uncovered. +Horse manure may be kept tightly rammed into well-covered barrels for +the purpose of removal in such barrels. Every person keeping manure in +any of the more densely populated parts of the District shall cause all +such manure to be removed from the premises at least twice every week +between June 1 and October 31, and at least once every week between +November 1 and May 31 of the following year. No person shall remove or +transport any manure over any public highway in any of the more densely +populated parts of the District except in a tight vehicle which, if not +inclosed, must be effectually covered with canvas, so as to prevent the +manure from being dropped. No person shall deposit manure removed from +the bins or pits within any of the more densely populated parts of the +District without a permit from the health officer. Any person violating +any of the provisions shall, upon conviction thereof, be punished by a +fine of not more than $40 for each offense. + +As with all such measures, the test comes with the enforcement, and +these regulations have not been well enforced, owing to the extremely +small corps of inspectors allowed to the Health Department, and to +other more pressing work. They can be made effective, however, and +it is earnestly hoped that not only Washington but other communities +as well will very soon be brought to a realization of the ease of +house-fly eradication and its very great desirability. + + + * * * * * + + +=The insect we now call the "house fly" should in the future be termed +the "typhoid fly," in order to call direct attention to the danger of +allowing it to continue to breed unchecked.--L. O. Howard.= + + + * * * * * + + +Transcriber Notes + +All illustrations moved to avoid splitting paragraphs. + + + + + + + + +End of the Project Gutenberg EBook of USDA Farmers' Bulletin 459: House Flies, by +L. O. Howard + +*** END OF THE PROJECT GUTENBERG EBOOK 59554 *** |