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LI E> R.AFLY 
 
 OF THE 
 
 UNIVERSITY 
 
 Of ILLINOIS 
 
 570 
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 no. I -24 
 cop. 6 
 
 NATURAL HISTORY 
 SURVEY 
 
 rURAl 
 HJS1 
 
Digitized by the Internet Archive 
 
 in 2011 with funding from 
 
 University of Illinois Urbana-Champaign 
 
 http://www.archive.org/details/dangerfromhousef04forb 
 
__ 
 
 The Danger from House-flies and 
 How to Control It 
 
 The house-fly pest is dangerous to health, and the cause of many deaths, es- 
 pecially of children, in summer time. To diminish this danger, keep the premises 
 clean and kill the flies; and to avoid it entirely, induce neighbors and town author- 
 ities to do the same. Clean up, keep clean, and kill the fly, is the 
 admonition of science to the householder, the community, and the city or town. 
 
 House-flies lay their eggs in a great variety of decaying or fermenting 
 substances — most frequently in the fresh manure of horses and cattle in 
 stables and barns, but often in kitchen garbage also, and in other and more 
 offensive household wastes. They hatch from the egg as footless, headless 
 maggots which feed upon the substances in which they were born. In the 
 course of a few days the maggot changes to a brown, oval, motionless ob- 
 ject called the pupa, and out of this comes the winged house-fly, soon ready 
 to produce eggs for another generation. In hot weather the eggs may 
 hatch, the maggot grow up and pupate, and the winged fly come forth, all 
 in from nine to fourteen days. In cool weather, these changes go on more 
 slowly. 
 
 The winged fly lives mainly on fluid or semifluid foods, some of which 
 are of kinds most dangerous to human health. Thus flies may sip up the 
 sputum of a person ill with consumption, in which are the germs by which 
 that disease is spread from one person to another; they may feed on the 
 wastes of a sick room, and on other filth, and so become fouled with fluids 
 containing the germs of typhoid fever, of summer complaint, and of dysen- 
 tery; and then they may visit our houses, restaurants, and groceries, 
 crawling over the food which we are about to eat, leaving a trail of disease 
 germs as they go, and they may infect the milk and other fluids which we 
 are about to drink. In this way they often spread abroad the most serious 
 diseases and cause the death each year of hundreds and thousands of peo- 
 ple, especially of children, in summer time in cities and towns. 
 
 Although in the maggot stage the house-fly may be of considerable 
 service as a scavenger, it does at best very imperfectly what we ought not 
 
to leave to the chance operations of insects, but should do systematically 
 and thoroughly on our own account. The winged fly, on the other hand, 
 is always a nuisance, and often a highly dangerous pest; and its destruction 
 is both a personal and a social duty. One who parmits flies to enter his 
 house or to get access to his food, is guilty of negligence likely to injure 
 his own health and that of his family; one who permits flies to breed on 
 his premises is to that extent himself a dangerous member of society; and 
 the community which does nothing to control the house-fly pest is to that 
 extent delinquent in the discharge of its duties towards its own people. 
 Every person may, it is true, protect himself in great measure, even if 
 living in a negligent community, but only with considerable trouble and at 
 unnecessary expense. Community work is necessary to complete success. 
 
 In order that house-flies may live and multiply, the adults must find 
 food for themselves and suitable places and substances in which to lay their 
 eggs; such substances must continue in a condition to serve as food for the 
 maggots until these have got their growth and have changed to the pupa; 
 this infested material must not be destroyed until the flies have escaped 
 from the pupa and taken wing; and then, of course, the winged flies must 
 live until they have laid a new lot of eggs. If any one of these conditions 
 can be suppressed, the house-fly itself will be suppressed also. 
 
 As this insect breeds only in substances which ought not to be allowed 
 to lie exposed, the plague of flies is a part of our punishment for unclean 
 surroundings; and to clean up and keep clean, is thus the first requirement. 
 In cities and towns the manure from a stable for a single horse should be 
 closely packed, every day, into one or more tight barrels or boxes with 
 close-fitting covers, and the contents of these receptacles should be hauled 
 away once a week, or even twice a week in warmest weather. In the 
 country, where the stables are larger, each should have an inclosure or pit 
 Into which the manure may be pitched daily, and from which it may be 
 hauled away. This inclosure must be made fly-proof by close-fitting doors, 
 but should have a screened opening for ventilation. Stables should have 
 floors which are water-tight, thus preventing the accumulation of moist, 
 fermenting material in which flies are likely to breed. Pits or bins in 
 which the manure is temporarily stored should be cleaned out thoroughly 
 when emptied, and if any fly pupae remain they should be killed by sprink- 
 ling lightly with kerosene. No garbage, offal, or decaying and fermenting 
 refuse of any description should be allowed to remain on the premises. 
 Even ashes become dangerous if mixed with moist garbage. Box privies, 
 If they can not be abolished, should at least be made fly-tight, and their 
 contents should be covered regularly with copperas, which will keep down 
 odors, and prevent the development of house-fly maggots. Garbage cans 
 should be kept tightly covered, and thoroughly cleaned out when emptied, 
 and sprinkled inside with kerosene to make sure that no larva* or pupa; 
 are left alive. Where flies are being bred in neighboring places beyond 
 
3 
 
 one's control, they must be kept out of the house, so far as possible, by 
 screened doors and windows, and caught and killed if they make their way 
 into the rooms. Sticky fly-paper, helped out by the favorite operation of 
 "swatting the fly", will ordinarily serve this purpose. An efficient fly 
 poison may be made by diluting formalin with five or six times as much 
 water, and adding sugar enough to make it sweet. This should be set about 
 in shallow dishes, and other liquids kept beyond the reach of the (lies. 
 Wire fly-traps, baited with attractive fly food, may be used to advantage in 
 the open air; for the number of flies which will seek admission to the house 
 may thus be diminished, as well as the number of fly maggots and of flies 
 of later generations to be bred in the neighborhood. 
 
 The principal contents of this little circular may be summarized large- 
 ly in the words of a poster issued by the Florida State Board of Health: 
 
 Flies breed in horse manure, cow dung, decaying vegetables, garbage of 
 all description, dead animals, and human excrement. 
 
 Flies are Nature's scavengers, it is true, but they become an intolerable 
 nuisance and DANGER when entering human dwellings and contaminat- 
 ing foods. 
 
 The presence of flies is a direct evidence of careless housekeeping and 
 the existence of filth in some form on or near the premises. 
 
 Remember that when and where absolute cleanliness prevails there will 
 be no files. 
 
 Look daily after the garbage cans. See that they are carefully sprin- 
 kled with hydrated lime or kerosene and effectively covered. 
 
 Remove all manure from stables every three or four days, and when re- 
 moved cover with hydrated high calcium lime. 
 
 Look carefully after the cuspidors. They require constant attention. 
 This is particularly true in hotels, boarding houses, station houses, railroad 
 stations, and, in fact, wherever people congregate in large numbers. 
 
 Flies are fond of feasting on tuberculosis sputum, and hover around 
 cuspidors. The specks of flies contain live tubercle bacilli after they have 
 eaten tuberculosis sputum, showing that the bacilli will pass through the 
 digestive tract of the fly in an active infective state. 
 
 Flies carry on their mouth parts, and on their legs, germs of decay and 
 disease, on which they have recently fed, and then crawl over food, infect- 
 ing it, unless shut out by screens. 
 
 Keep flies from the SICK, especially those ill with communicable or 
 contagious diseases. If the room is not screened the patient should be 
 treated under a net, both for safety to others as well as for individual com- 
 fort. 
 
 SCREEN ALL FOOD. Apply this rule, not only to food prepared at 
 
home, but to food-stuffs offered for sale, and especially fruits, salads, and 
 all other things which do not require to be cooked; for — 
 
 Flies crawl over fruit when exposed for sale, unguarded by screens, and 
 many people do not wash fruit before eating it. This is a common source 
 of human infection, particularly if a case of typhoid fever near by is being 
 carelessly handled. 
 
 Don't forget that flies will carry the bacilli of typhoid fever from the 
 stools of the patient (if left exposed and not disinfected), if given an op- 
 portunity, to the food in the kitchen and dining-room. 
 
 The great secret of freedom from flies is CLEANLINESS, FIRST, and 
 a screening of all openings of the home, especially of the kitchen and the 
 dining-room. 
 
 Stephen A. Forbes, 
 
 .State Entomologist. 
 Urbana, Illinois, 
 June 1, 1911.