PART II ECONOMIC ENTOMOLOGY 



CHAPTER XIV 

 INSECTS AFFECTING MAN AND DOMESTIC ANIMALS 



112. House Flies (26).* The house fly is too well known 

 to need description. It will hardly be confused with any 

 other species except, possibly, the stable fly (p. 180), from 

 which it may be distinguished by the absence of the strong 

 piercing mouth-parts which enable the latter species to 

 bite and by the six dark lines on -the thorax. Smaller flies 

 belong to other species, contrary to the popular notion that 

 little flies grow larger as the season advances. Careful 

 counts have shown that practically 99 per cent of the flies 

 found in dining-rooms are house flies. 



"Musca domestica commonly lays its eggs on horse 

 manure. This substance seems to be its favorite larval 

 food. It will oviposit on cow manure, but we have not been 

 able to rear it in this substance. It will also breed in human 

 excrement, and from this habit it becomes very dangerous 

 to the health of human beings, carrying, as it does, the germs 

 of intestinal diseases such as typhoid fever and cholera 

 from excreta to food supplies. It will also lay its eggs on 

 other decaying vegetable and animal material, but of the 



* Musca domestica Linn. Family Muscidce, see page 141. Numbers 

 in parentheses refer to publications cited in Appendix A, which 

 should be consulted for more detailed information. 



175 



