CONTEXTS. 
Paere 
Introduction 7 
Importance and early history 7 
Original habitat of Hessian fly 9 
Distribution 10 
Means of distribution 11 
Outbreaks in spring- wheat regions in Northwestern States 13 
Description and life history 14 
Development 17 
Annual generations 18 
Food plants 25 
Effect upon the plants 27 
Natural enemies of the Hessian lly 27 
Primary parasites 28 
Merisus destructor 31 
Bteotomns subapterus 32 
Pteronialns pallipes 33 
Eupelmus allynii 31 
Platygaster herrickii .'. 35 
Polygnotns hiemalis 35 
Lygocerns triticum 36 
Secondary parasites 36 
Tetrastichus productus 36 
Tetrastichus ca rinatus : 37 
Utilization of parasites 37 
Introduction of Entedon epigonus 38 
Other natural enemies 41 
Nematode worms 41 
Thrips 11 
Remedies 41 
Burning the stubble Ii' 
The plowing under of stubble 43 
Destruction of volunteer wheat 43 
Planting of decoy strips 43 
Early or late sowing of tall wheat II 
Intermittent wheat culture 45 
Pasturing with sheep 4"> 
Rolling 4t! 
Mowing LG 
Selection of resistant varieties <>f wheat 46 
Use of insecticides IT 
Combination of remedial measures 48 
Bibliography L8 
Explanation of plates 58 
B 
