THE FLIES 37 



during warm and sunny weather, their harassing bites cause much 

 torture to horses and cattle. They do not fly in cloudy weather, and 

 they perish with the frosts of early autumn. 



Family IV. Muscid^ 



Diptera (p. 23). — These flies are small to moderately large, with bodies 

 thinly covered with hairs or bare. The bristles of antennae are feathery. 

 The abdomen is four-segmented and smooth except for bristles near the 

 tip. 



The larvse are apodal maggots, feeding upon decaying animal or veg- 

 etable matter. 



MUSCA DOMESTICA 



The common house fly (Fig. 8). Muscidae (p. 37). — The mature in- 

 sect is one-fourth to five-sixteenths of an inch in length; dorsal region of 

 thorax grayish in color and bearing four longitudinal stripes; abdomen 

 yellowish. The mouth parts are trumpet-shaped, adapted for sucking 

 up Hquids but not for piercing. 



Life History. — In about ten days after emerging from the pupal 

 case the female fly seeks suitable material upon which to deposit her 

 eggs. This may be any decaying vegetable matter, though usually 

 horse stable manure. About one hundred eggs are deposited at each 

 laying, of which there are several at intervals of three to five days. In 

 eight to twenty-four hours a white, footless larva is hatched. After 

 five days to one week of feeding and and growing, during which period 

 it undergoes two molts, the larva enters the pupal stage, the larval skin 

 serving as its puparium. Before entering this stage the maggot may 

 crawl away from its breeding place and burrow for a short distance 

 into the adjacent ground, or find lodgment under a board, stone, or 

 dried crust of manure. The stage of pupation lasts from five days to 

 one week, and at its termination the adult fly emerges. 



According to the longer periods given, the time required for develop- 

 ment from the egg to the imago is fifteen days. This time, however, is 

 greatly influenced by temperature, under the most favorable conditions 

 of which the period for complete metamorphosis may be reduced to ten 

 days; a fact always to be reckoned with in dealing with control of the fly 

 through the regular and systematic removal of stable manure or other 

 material which may serve as its breeding bed. 



In the warm midsummer season adult flies may live for six to eight 

 weeks, though it is probable that the average period will not exceed 

 thirty days. They may survive the winter in a state of hibernation, 

 seeking their retreats in the late fall months, and coming forth with the 

 warm days of early spring to crawl upon the windows as they seek the 

 warm sunlight or exit from houses. 



