342 



Tlie l\vo-\vinged Flies 



Most abundant, most wide-spread, and most important to us of all the 

 Muscid flies are the common house-flics. They belimi^ with some other 

 simihir forms to the subfamily Muscina-. A number of species may be 

 found in houses, but the true house-fly, Musca domeslica (Fig. 483), is by 

 far the most numerous. Dr. Howard, government entomologist, who has 

 ])aid special attention to the life of house-flies and moscjuitoes, because of 

 their dangerous disease-germ carrying habits, says that house-flies undoubtedly 

 contribute materially in the dissemination of infectious diseases by carrying 

 germs in the dirt and filth on their feet, collected during their pilgrimages 

 to the contents of cuspidors, slop-pails, and closets. He advocates a definite 

 crusade against the house-fly like the one now being undertaken in this 

 country against the mosc]uito. 



Fig. 485. 



Fig. 485. — Larva of house-fly, Musai donuslka. (.Vfter Howarrl and Marlatf, three 



times natural size.) 

 Fig. 486.^Pupa, in puparium, of house-fly, Musca domeslica. (.\fter Howard and 



Marlatt; three times natural size.) 



The eggs of the house-fly are laid in horse-manure, occasionally in other 

 e.xcrementitious or decaying matter. Each female lays about one hundred eggs. 

 These eggs hatch in six or seven hours, and the slender pointed white larvae 

 called maggots (Fig. 485) lie in their plentiful food-supply for the five or six days 

 necessary for their full growth. They pupate within the last larval skin, which 



thickens and turns brown at the time of pupation 

 (Fig. 486). The pupal stage lasts five days, and 

 then the fly issues. Its food is liquid and taken 

 up by lapping. The "house-fly" that bites is 

 not the true house-fly, but u.sually the fiercely 

 piercing stable-fly, Slomoxys cakilrans, another 

 member of the subfamily, which looks much like 

 Musca and which is a not infrequent visitor in 

 the hou.se. 



This stable-fly and another ally of the house- 

 fly, called the horn-fly, are great posts of stock. 

 The horn-fly, Hamatobia serrata (Fig. 488), which 

 gets its popular name from the habit of clustering, when not feeding, on the 

 bases of the horns of cattle, is a European insect that was accidentally brought 

 to this country in 1886 or 1887. 



It quickly established itself, and in two years had spread over the eastern 



Fig. 487.— a stable-fly, Slo- 

 moxys calcilrans. (Three 

 times natural size.) 



