in the fence corners will carry the species over winter in the 

 seed . . ." (p. 581). Exactly. And if these heads were cut 

 in the spring before adults can develop and were subsequently 

 cut whenever they became nearly old enough to mature a crop 

 of adult midges, these same patches would constantly act as 

 traps and keep the sorghum clear to that extent. It will be 

 readily seen that the best results for a given effort are secured 

 by making the trap patch of Johnson grass as far as practicable 

 the only oviposition material for the time being. 



There is every reason to believe that it will be possible to 

 work out a similar method of trapping for the control of the 

 wheat midge. 



Of wheat insects the Hessian fly stands first, with the 

 joint worm second. The Hessian fly, on winter wheat, can be 

 most easily controlled by providing a trappatch in the fall, 

 having it sprout at the same time as volunteer wheat. This 

 trappatch, and other places where volunteer wheat freely 

 occurs, will thus attract the bulk of the insects. The main 

 crop is sown comparatively late, the date depending primarily 

 upon rainfall affecting the early or late emergence of the flies 

 in the fall as the case may be, and the development of volun- 

 teer wheat. The aim naturally is to have the flies oviposit on 

 the trappatch and volunteer wheat while, the main crop is 

 sprouting. This trappatch and the places where volunteer 

 wheat freely occurs must be plowed unHer in the late fall or 

 anyway not later than in the spring before emergence of 

 the flies begins. Thus a field the previous year in wheat may- 

 be allowed to carry winter wheat up to the time of the begiu- 



9 



