278 ORDER DIPTERA 



The house fly {Musca doDicstica) is perhaps the most 

 uni\ersal, and occurs wherever civihzation extends, and 

 presents an important feature in its possibilities of carrying 

 disease germs. One of the first cases estabhshing this con- 



FiG. 223. — The common house fly: a, full-grown larva; b, one of its 

 anterior spiracles; c, antenna; d, hind end of body showing anal spiracles; 

 e, side view of head; /, head from above; g, head of young larva: h, eggs. 

 All enlarged. (From Howard, Div. Ent , U. S. Dept. Ag.) 



nection was that determined during the Spanish-American 

 war, where the source of the typhoid was traced to house flies. 

 It is known to serve as a carrier for tuberculosis, dysentery 

 and other diseases. Flies breed in filth, especially horse 

 manure, the eggs requiring a few hours to hatch, the mag- 



