INSECTS INJURIOUS TO WHEAT. 123 



abandonment of the wheat crops in some localities through- 

 out northern New England. Serious damage was reported 

 as due to this pest every few years until about 1860, being 

 most severe in 1854, — in which j^ear Dr. Fitch estimated 

 the loss in Nevv York alone at 815,000,000, — 1857, and 



Fig. 70. — Wheal -midge (Diplosis triU-i). a, female fly; h, male 

 fly; c, larva from below. (After Marlatt, U. S. Dept. Agr.) 



1858. Since then no wide-spread injury has occurred, 

 though local outbreaks are frequent, and it has spread 

 south to the Gulf States and westward to Iowa, Minnesota, 

 and Arkansas. 



Life-lmtovy. — The adult flies are small, two-winged 

 insects, about an eighth of an inch long, of a yellow or 

 orange color. They appear about the middle of June and 

 lay the eggs "'in a small cavity at the summit of, and 

 formed by a groove in, the outmost chaff covering the 

 incipient kernel.^' They hatch in about a week, according 

 to Dr. Fitch, and the maggots burrow into the fonning 

 t.ernels. The maggots are of a reddish color, and when 



