The House Fly and How to Suppress It — Story, Setting & Ideas

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U. S. DEPARTMENT OF AGRICULTURE

FARMERS' BULLETIN No. 1408

_The_ HOUSE FLY AND HOW TO SUPPRESS IT

The presence of flies is an indication of uncleanliness, insanitary conditions, and improper disposal of substances in which they breed. They are not only annoying; they are actually dangerous to health, because they may carry disease germs to exposed foods.

It is therefore important to know where and how they breed, and to apply such knowledge in combating them. This bulletin gives information on this subject. Besides giving directions for ridding the house of flies by the use of screens, fly papers, poisons, and flytraps, it lays especial emphasis on the explanation of methods of eliminating breeding places and preventing the breeding of flies.

This bulletin supersedes Farmers' Bulletin 851.

Washington, D. C. Issued April, 1925; revised November, 1926

THE HOUSE FLY[1] AND HOW TO SUPPRESS IT.

By L. O. HOWARD, _Chief of the Bureau of Entomology_, and F. C. BISHOPP, _Entomologist_.

CONTENTS. Page. Kinds of flies found in houses 1 Where the true house fly lays its eggs 2 How the house fly passes the winter 6 Carriage of disease by the house fly 6 Excluding and capturing flies 7 The use of screens 7 Fly papers and poisons 8 Fly sprays 8 Flytraps 9 Preventing the breeding of flies 9 Construction and care of stables 9 Fly-tight manure pits 10 Frequency with which manure should be removed in cities and towns 10 Health office regulations for control of house flies in cities 10 Disposal of manure in rural and suburban districts 11 Chemical treatment of manure to destroy fly maggots 12 Maggot trap for destruction of fly larvæ from horse manure 13 Compact heaping of manure 15 Garbage disposal and treatment of miscellaneous breeding places 15 Sewage disposal in relation to the prevention of fly-borne diseases 15 What communities can do to eliminate the house fly 16

KINDS OF FLIES FOUND IN HOUSES.

Several species of flies are found commonly in houses. Some of them so closely resemble the true house fly that it requires very careful observation to distinguish them from it.

One of these is the biting stable fly[2] (fig. 1). It occurs frequently in houses and differs from the house fly in the important particular that its mouth parts are formed for piercing the skin. This fly is so often mistaken for the house fly that most people think that the house fly can bite.

Another frequent visitant of houses, particularly in the spring and fall, is the cluster fly.[3] It is somewhat larger than the house fly, and is distinguished by its covering of fine yellowish hairs. Occasionally this fly occurs in houses in such numbers as to cause great annoyance. It gets its name of "cluster fly" from its habit of collecting in compact groups or clusters in protected corners during cold periods.

Several species of metallic greenish or bluish flies also are found occasionally in houses. These include a blue-bottle fly,[4] the black blowflies,[5] and the green-bottle (fig. 2) flies.[6] They breed in decaying animal matter.

[Footnote 1: _Musca domestica_ L.] [Footnote 2: _Stomoxys calcitrans_ L.] [Footnote 3: _Pollenia rudis_ Fab.] [Footnote 4: _Calliphora erythrocephala_ Meig.] [Footnote 5: _Phormia regina_ Meig. and _P. terrae-novae_ Desv.] [Footnote 6: _Lucilia caesar_ L., _L. sericata_ Meig., and other species of the genus.]

There is still another species, smaller than any of those so far mentioned, which is sometimes called the "lesser house fly."[7] This insect is distinguished from the ordinary house fly by its paler and more pointed body. The male, which is commoner than the female, has large pale patches at the base of the abdomen, which are translucent when the fly is seen on the window pane. These little flies are not the young of the larger flies. Flies do not grow after the wings have once expanded and dried.

[Footnote 7: _Fannia canicularis_ L.]

In late summer and autumn many specimens of a small fruit fly, known as the "vinegar fly,"[8] make their appearance, attracted by the odor of overripe fruit.

All of these species, however, are greatly dwarfed in numbers by the common house fly. In 1900 the senior author made collections of the flies in dining rooms in different parts of the country, and found that the true house fly made up 98.8 per cent of the whole number captured. The remainder comprised various species, including those mentioned above.

[Footnote 8: _Drosophila ampelophila_ Loew.]

WHERE THE TRUE HOUSE FLY LAYS ITS EGGS.

The true house fly (fig. 3), which is found in nearly all parts of the world, is a medium-sized fly with four black stripes on the back and a sharp elbow in one of the veins of the wings. The house fly can not bite, its mouth parts being spread out at the tip for sucking up liquid substances.