My daughter has this thing about bugs. The sound of a nearby fly can send her into a panic; the sight of one causes a full-blown meltdown. Summer approaches rapidly, and we have begun to see the occasional housefly in our home and with them a proportionate increase in her outbursts. We wish she didn't react quite so strongly to their presence - in the age of modern sanitation, a fly here or there is not a major problem, but her reaction would be quite justified at the beginning of the 20th century, according to the classic encyclopedias of the time.

The 11th edition of the Encyclopædia Britannica, in its article on the "Fly" (vol. 10, p. 584), refers to an interesting study conducted by the Department of Agriculture in 1909: Mr L. O. Howard (Circular 71 of the Bureau of Entomology U.S. Dept. of Agriculture, Washington, 1906) says that in 1900 he made a collection of the flies in dining-rooms in different parts of the United States, and out of a total of 23,087 flies, 22,808 were the common house-fly. Its geographical distribution is of the widest, and its rapidity of breeding, in manure and dooryard filth, so great that, as a carrier of germs of disease, especially cholera and typhoid, the house-fly is now recognized as a potent source of danger; and various sanitary regulations have been made, or precautions suggested, for getting rid of it. These are discussed by Mr Howard in the paper referred to, but in brief they all amount to measures of general hygiene, and the isolation, prompt removal, or proper sterilization of the animal or human excrement in which these flies breed.

Howard is also the leading authority quoted in the 1924 Encyclopedia Americana (vol. 11, pp. 352-354). Below are some excerpts from the article "Flies:"

A type of the group [those which cause "serious evils to mankind"] is found in the house-fly (Musca domestica), which represents the great family Muscidæ, in which most of the familiar flies about houses and stables are included, and its life-history represents that of its kind generally. Its eggs are laid preferably on horse-manure, but also on human or other excrement, decaying vegetables, etc., and hatch in six or eight hours, producing maggots. These mature in four or five days, when their skins harden and turn brown, forming a puparium, or case, within which the true pupa forms, and five days later gives birth to a perfected fly. Thus a total life cycle requires in midsummer only about 10 days, and a dozen generations may thus be born in warm climates within a single season. As each fly deposits on the average 120 eggs, and as the maggots of 1,200 house-flies may be sustained by a pound of manure, the possible rapidity of their multiplication is apparent. Most flies live but a few weeks, and toward the end of the season they die with great rapidity, becoming infested with reddish mites, which suck their juices, or with fatal fungous diseases. (See Fungi). In warm houses a few may survive a winter, but as a rule all adult flies die in the fall, and the species survives and recovers in the spring from the eggs or pupa left over winter in the manure-heap or other feeding-place. It is plain that attempts to mitigate the annoyance and danger resulting from many flies may best be directed toward the destruction of their eggs and young. That such destruction is desirable and the duty of society is plain when one considers the vast amount of injury these insects may do. [...]

Dr. L. O. Howard, of the United States Department of Agriculture, has given special attention to this matter, and has found that no less than 77 species of flies frequent human excrement and are therefore liable to obtain and carry disease germs. As the innumerable insects themselves are beyond reach, the measures for protection must be preventative. Dr. Howard says that in order to avoid epidemics of typhoid fever it is necessary to abolish the box privy, prevalent in rural and village districts, and substitute earth-closets, where water-closets cannot be installed; to place stable manure in receptacles and treat it with chloride of lime to destroy the maggots, throwing a shovelful over each day's addition. Pantries, dining-rooms and kitchens should be carefully screened to keep out flies; and especial pains taken in summer to keep flies out of sick-rooms. Detailed instructions and the reasons for them are given by Howard in his pamphlet, 'How Insects Affect Health in Rural Districts,' issued as Farmers' Bulletin 155, by the United States Department of Agriculture.

The article on the "Fly" in the 1919 World Book (vol. 4, pp. 2231-2235) is quite sensational and very thoroughly illustrated, but it is also charming in its optimistic belief that most people will rally behind science and facts to come together and solve large societal problems. I've reproduced the full article with pictures below:

Fly. "A fly," wrote a small boy who had had a lesson in school on the harm the little pest can do, "is more dangerous than a lion, but I would rather have a fly bite me than a lion." Not many years ago flies were looked upon as a necessary nuisance; they were troublesome, but they were not dangerous, people thought, and there was no possible way of getting rid of them. A half-century ago it was common at mealtime during the summer months to have a servant or one of the children of the family stationed near the table with a leafy branch, wherewith to wave away the flies which were thick in the dining-room. A little later nettings were introduced, and then came wire screens, to keep out as many as possible; but to-day such measures are looked upon as all too passive, because the deadly nature of the insect is understood, and regular crusades are instituted against the fly.

But why? What can this little insect do that makes it as "dangerous as a lion," and has caused "Swat the fly" to become a slogan? Before discussing this question it is necessary to learn something about the insect.

What a Fly Is. The name fly is applied to many different kinds of insects; in fact, more than 40,000 species are known to-day, but they all have certain traits in common. The most noticeable of several resemblances is the fact that they have but two wings; the scientific name for flies is Diptera, which means two-winged. No other known insect has two wings except one little scale-insect. The wings of flies are always transparent, never folded as are the wings of grasshoppers, and they have prominent lengthwise veins. Instead of hind wings most flies have two small, rod-like organs which probably help the insect to balance and steer itself in flight. The head of a fly is usually small; by far the larger part of it is made up of two wonderful eyes, which are often composed of thousands of facets which enable their owner to see in almost any direction. A few species are provided with sucking mouth-parts, but fortunately the common house fly is not thus equipped.

The Commonest Fly. Of the true flies, a number of groups are very well known, as the gnats, blow flies, midges and mosquitoes; and the name is often applied to certain insects to which it does not really belong, as the dragon fly and the May fly. But there is one true fly which is so common all about the haunts of man that it has received the name of domestic fly, or house fly, and it is this little creature which is meant when the term fly is used without modification.

Life History. There are some very interesting things about the house fly. Every child has watched with wonder its progress across the ceiling, to which it is held by the suckerlike hairs on its feet; but nothing about it is more remarkable than the amazing rapidity with which it breeds. If there were alive in the world at the beginning of April but one fly, and that an egg-laying female, there might be six months later, if all the eggs laid came to maturity, no fewer than 131,220,000,000,000,000,000 flies — over 131 quintillions of descendants of that one first fly! What wonder is it that a neighborhood which seemed free from flies may in a week or two be swarming with them!

The female lays her eggs in any warm, damp, decaying matter, whether it be the manure of a stable, the filth of a pig's pen or the fermenting garbage; and there the little white maggots are hatched out. Soon these change into pupae (plural of pupa, the intermediate state), and in from eight to fourteen days emerge as mature flies. Led by its strong sense of smell, the young fly hastens from its filthy hatching place to the nearest food-supply spot — perhaps an imperfectly screened kitchen or the baby's milk, where it begins to be indeed a deadly enemy.

Harm Done by Flies. Occasionally some person objects that the fly is receiving more than its share of censure, claiming that a little stingless insect cannot be one of the most dangerous things in the world; but doctors and scientists are ready with facts to prove the contrary. It is no longer a theory but a well-established fact that flies cause many of the cases of typhoid; that "summer complaint" might well be called "fly complaint," so clearly is it spread by flies; that tuberculosis and all filth diseases are carried by it; that domestic animals owe many of their diseases to its agency — in fact, that flies cost in Canada and the United States hundreds of millions of dollars and scores of thousands of lives every year.

How they accomplish all this is very evident, since their hairy legs are peculiarly well fitted for carrying germs and filth particles from their favorite breeding-haunts to food often left exposed for them to walk upon. More than 6,000,000 bacteria, it has been estimated, can be carried by one fly on its body as it flies from the manure pile or the spittoon or the sick room to the baby's lips or to the sugar bowl. It is not chance that the fly season coincides with the season of dangerous intestinal diseases and, very largely, with the typhoid season; it is a clear case of cause and effect.

Facing the Fly Problem. The average person feels helpless and hopeless in facing the question of what is to be done about it. "There always have been flies, therefore there always will be flies," is his opinion, despite any little efforts on his part. Serious, scientific men have faced the problem in a sober-minded, scientific manner, and have found ways and means which, if generally adopted, would do much toward ridding the world of this pest. In agricultural communities, such favorable breeding-grounds as manure heaps and open swill barrels can be replaced by covered manure bins and screened-top barrels, and the flies be kept down; cities and villages, however, may, with proper care, be flyless.

Some of the remedies are easy to apply and have been employed for many years. Windows and doors may be screened and "sticky fly-paper" may be placed to catch those which do slip in; but this is not beginning at the source. First of all, the fight must be carred out-of-doors. "why not," asked a thirteen-year-old boy, who had become interested in the extermination of flies, "put all the flies in jail and let ourselves out?" The annual cost of screening windows and doors, estimated for the United States and Canada at $15,000,000 would, if properly expended, make screens unnecessary.

Preventive Methods. The first step in a definite campaign is to kill the winter fly — the occasional specimen that survives in a sheltered place and in the spring crawls out to bask and gain strength in the sunshine. Kill it without pity — it may be that thereby the world is being rid of countless millions of summer flies. Until these winter flies have obtained abundant food they cannot lay eggs, and as they are extremely hungry they are easier to catch in traps than at almost any other time. If every family in a community would in the early spring days get rid of every fly about the premises there would be no summer campaign, and noonday meals could be eaten on unscreened porches with pleasure and with safety.

Next, breeding-places should be done away with, so far as possible, by providing proper sanitation and by banishing all unnecessary garbage and rubbish. Refuse should be buried or covered with kerosene and burned. Outside slop barrels should be scalded, and in communities where domestic animals are raised care should be taken to have them and the premises kept in a sanitary condition. Much of this work can be done by families in and about their homes; much remains to be done by the public authorities, who can best be urged to a proper conception of their task by enlightened public opinion. Indeed, it may be said that only as community feeling is aroused can really effective work be done, for what good does it do a family to rid its own home of flies so long as the meat it gets from the market and the butter and milk it gets from the dairies are contaminated by their presence?

The Active Fight. If the work of prevention by means of killing winter flies and destroying breeding-places is begun early enough, it is all-sufficient; but even if a few flies have been allowed to reproduce themselves and their descendants in their turn have been allowed to breed, the fight is not yet hopeless, though it is rendered more difficult.

It remains but to catch the flies as soon as possible after they have emerged, before they have reached the egg-laying stage; for it is well to remember at every stage of the campaign that the fly must feed for two weeks before it can lay its first eggs. And these young flies should be caught out-of-doors, before they have had time to carry filth germs into the house. Somewhere near every house, whether it be in the city or in the country, there is a garbage pail — the flies' favorite feeding-ground. Now if, as they swarm about this, they can be coaxed by some especially attractive bait into a trap which stands above the garbage pail, the work is done, in large measure. Then if another trap be placed outside the screen door, and another in the stable window or barnyard, it is not likely that many flies would feed through the whole two weeks without getting caught. The "catch" may be quickly killed by immersion in boiling water, or by fumigation with sulphur. Humane methods should be employed, even with flies.

Traps may be bought at a reasonable price, or they may be constructed at home still more cheaply. Any box or other receptacle of transparent material, provided with a crack at the bottom and baited with banana peel, sugar and vinegar, meat or other food attractive to flies, will serve the purpose. One point must be borne in mind — the crack at the bottom must not be too wide, or the flies will crawl out after they have fed and then proceed to lay their eggs. The crack should never be more than a quarter of an inch in width and should open up toward the bait and not down, as flies show a strong tendency to crawl upward toward the light.

Summary. It may sound at first somewhat visionary — this campaign which has as its aim to "get the last one" — but it has been proved to be sane and practical. Small towns have rid themselves almost completely of the pests; big cites have done such effective work that in the huge public markets no more than half a dozen flies may be found at one time; and neighborhoods have won for themselves relief from the nuisance when other parts of the city have swarmed with flies. These insects do not travel great distances, and a neighborhood campaign will be effective even though the town as a whole does not take up the work. It can be done — that much is certain; but it will be done only when the people are convinced of the absolute necessity. When a housewife begins to feel that it is a disgrace, a sure sign of untidiness and careless housekeeping to have even one fly about; when the storekeeper or dairyman is made to realize that he is looked upon as a spreader of disease if he does not protect his products; when a community really appreciates the fact that not only unpleasantness but sickness and death result from the presence of flies — then, and not till then, the campaign will be undertaken in earnest. The United States Department of Agriculture has shown an active interest in the problem and has for distribution bulletins which discuss the fly in all its phases, suggesting effective means of combating the danger the fly creates.

W.A.E.

Consult Cragin's Our Insect Friends and Foes; Comstock's Insect Life; Ross's The Reduction of Domestic Flies.