8 FARMERS’ BULLETIN 679. 
time between the emergence of the adults and the first deposition of 
eggs is considerably shorter than was previously thought to be the 
case. Only three or four days are necessary in midsummer for the 
female to reach sexual maturity. As in the case of other periods of 
its hfe history, so the preoviposition period is considerably pro- 
longed by the lower temperatures of spring and autumn. In mid- 
summer, With a developmental period of from eight to ten days from 
egg to adult, and a preoviposition period of from three to four days, 
there would be a new generation started every 11 to 14 days. There 
is thus abundance of time in the climate of Washington for the devel- 
opment of 10 to 12 generations every summer. 
Fic. 11.—Larve, or maggots, of the house fly. About natural size. (From Newstead.) 
The hibernation of the house fly is a subject to which considerable 
attention has recently been given, and many new points of practical 
importance have come to light. The prevailing idea that the house 
fly passes the winter as an adult, hiding in the cracks and crevices of 
buildings and in straw stacks, ete., has never been proved experi- 
mentally. Messrs. Bishopp, Dove,and Parman made attempts to keep 
adults in large cages through the winter of 1913-14 at Dallas, Tex. 
In one experiment in which the cage was kept in a building which 
was heated during cold periods some flies remained alive for 53 
days. In some experiments carried out by the junior author at New 
Orleans during the same winter all the flies died within a period 
of 30 days, most of them as a result of the attack of a parasitic 
