UITOES AND FLIES
tic pest to people that live indoors, is intimately associated with the stable. Its favorite breeding place is the manure pile. Here the female fly lays her eggs (B), and here the larvae, or maggots (Ç), l?ve until they are ready for trans- formation. It is estimated that fully ninety-five per cent of our house files have been bred in horse manure. A few may come from garbage cans, or from heaps of vegetable refuse, but such sources of fly infestation are comparatively unimportant. Measures of fly control are directed chiefly to preventing the access of files to stable manure and the destruction of maggots living in it. The eggs of the bouse fly IFig. ?82 B) are small, white, .elongate-oval objects, about one twenty-fifth of an inch m length, each slightly curved on one side and concave on the other. The female tir begins to lay eggs in about ten days after having transformed to the adult form, and she deposits from 75 to ?5o eggs at a single laying. She re- peats the laying, however, at intervals during her short productive period of about twenty days, and in all may deposit over 2,ooo eggs. Each egg hatches in twenty-four hours or less. The larva of the house tly, in common with that of many other related files, is a particularly wormlike creature, and is commonly called a maggot IFig. 182 D). Its slender white body is segmented, but, in external appearance, it is legless and headless. On a fiat area at the rear end of the body are located two large spiracles (P,çp), which the novice might mistake for eyes. The tapering end of the body is the head end, but the true head of the maggot is withdrawn entirely into the body. From the aperture where the head bas disappeared, which serves the maggot as a mouth, two clawlike hooks project (?,?h), and these hooks are both jaws and grasping organs to the maggot. The larva sheds its skin twice during the active part of its life, which is very short, usually only two or three weeks. Then it crawls of? to a secluded place, generally in the earth beneath its manure pile, where it enters a resting condi-
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INSECTS
