44 N. H. AGR. EXPERIMENT STATION. [Bulletin 171 



were collected on days of rain. In this year there seems to be 

 an evident acceleration of emergence immediately following 

 rainfall, even though the precipitation was slight. Further, the 

 month of June was one of great drouth in 1913, the total rainfall 

 being only .20 inch up to July 10. There had been no emergence 

 noted up to that date. With a slight precipitation on July 10 

 emergence began. 



Extreme heat seemed to retard emergence of the flies or per- 

 haps to kill many of them before they were collected in the daily 

 examination of the cages. Thus the records on July 3 and 4, 

 1911, when the temperature rose to 103 each day, fell off in 

 marked degree. The same was true on July 10, 1911, ^^^th a 

 temperature of 101. 



MANNER OF EMERGENCE OF FLIES. 



At various times from June 29 to July 6, 1911, observations 

 were made of the behavior of flies on emergence from the 

 ground. 



On first coming to the surface flies are vigorous and active. 

 They are as yet light in color, and the wings are not expanded. 

 For a time they crawl around rapidly, seemingly searching for a 

 suitable place for expanding and drying the wings. Occasion- 

 ally one will jump, somewhat like a spider. In spite of their 

 activity, however, flies that fell on their backs seemed unable to 

 right themselves, and died. 



The length of time required for the wings to expand and dry 

 varied from forty-three minutes to an hour. Usually about 

 forty-five minutes was needed. 



The flies did not attain the normal dark color until about an 

 hour after the wings were expanded, and flight was not much 

 indulged in until this additional period was over. Thus the 

 total length of time from the first appearance above ground to 

 active, normal flight was an hour and a half or more. 



PERIOD AFTER EMERGENCE BEFORE EGG-LAYING BEGINS— 



MINIMUM LENGTH. 



In 1911 and again in 1913 repeated and somewhat elaborate 

 attempts were made to maintain newly emerged flies under 

 definite observation for an extended period in surroundings as 



