INSECTS INJURIOUS TO SMALL GRAINS 135 



the number escaping would be greatly reduced," for, as the 

 adults emerge soon after harvest, they would escape to deposit 

 their eggs were the straw left in the fields, but "it is not likely 

 that those in the centre of the stacks would be able to make 

 their way out, and the threshing-machine would destroy many 

 more. How much could be accomplished by late sowing of grain 

 is uncertain, as the females are known to occur abundantly up to 

 October. If plots of grain were sowed immediately after harvest 

 in the vicinty of the stacks, many of the females could, no doubt, 

 be induced to deposit their eggs therein, and these could be 

 destroyed by plowing under." Burning of the stubble will also 

 aid in keeping this pest under control. 



There are several undetermined species of flies belonging 

 to the genus Oscinis, which have practically the same life history 

 as the wheat stem-maggot and injure the wheat in the same 

 manner. They very closely resemble the common house-fly in 

 miniature, being about one-fourth as large. They will not need 

 consideration by the practical farmer other than in applying 

 methods of control as already given. One species of this genus, 

 determined by Professor H. Carman as Oscinis variabilis Loew and 

 christened the American Frit-fly, has been found common in 

 Kentucky and Tanada, but in the larval stag? is so nearly 

 identical in appearance and habit with t'.ic stem-maggot that it 

 can with difficulty be distinguished from it. 



That these pests do not do more injury is probably due, to a 

 considerable extent, to the fact that large numbers of them are 

 destroyed by a small hymenopterous parasite, known as Coelinus 

 meromyza; Forbes, which very commonly infests the larvae, and 

 by other parasites and predaceous insects. 



Rarely will these pests do serious damage, but very often 

 it is sufficient to merit consideration, and only a knowledge of 

 their life history can give a key to their successful control. 



