INJURING THE HEADS. 231 



of the stem ; but, being secure from ordinary obser- 

 vation, they are seldom noticed. We have found 

 five of these larvae at work on a single stem. These 

 worms do not usually wither the straw, and the 

 effect of their work is only to be observed in the 

 shorter and more slender stem, shorter heads and 

 smaller and less plump kernels. 



" The larvae are almost invariably found below the 

 upper joint, and hence, by cutting the grain a little 

 high, they can be left in the field, and as they pass 

 the winter as pupae in the same situation, by burn- 

 ing the stubble any time between harvest and the 

 following March, they can be destroyed. As the 

 adults emerging from the old straws in spring are 

 almost invariably wingless, they cannot travel about 

 very rapidly. And hence changing the grain from 

 one field to another, or rotating the crop, is often 

 quite effectual in keeping them in check. Those 

 adults appearing in June from the growing plants, 

 are provided with well developed wings, and can 

 travel about from field to field with the utmost 

 freedom." 



INJURING THE HEADS. 



The Wheat Midge. 



Cecidomyia tritici. 



This insect is closely related to the Hessian fly. 



The adult is a small, two-winged, yellow or orange 



colored fly that appears in the wheat fields a few 



weeks before harvest time, and deposits its minute 



