104 



INSECTS INJURIOUS TO STAPLE CROPS. 



appearance of the fall brood, a season of drought in early 

 September retarding the emergence of the flies until rain 

 falls. Professors Roberts and Slingerland state that ''a 



mild October and November often emphasizes the fly's 

 destructiveness. A damp spring, even though a cold one, 

 is also favorable to the development of the insect. On the 

 contrary, dry hot summers are unfavorable, and often 



