10 



INJURIOUS INSKCTS OF if)o.r 



3. All screenings and litter about the threshing machine 

 should be cleaned up and either fed immediately or burned, leav- 

 ing no litter from the threshing on the field. There is no abso- 

 lute need of burning the straw pile. The flies emerging from 

 "flax seeds" in the center of the pile will never reach the surface. 



4. Since the fly lays its eggs as a rule near the locality where 

 it emerges from the "flax seed," it is best not to plant wheat on 



k\a\i ill ft 



Fig. 7. — Merisus, a parasite of Hessian Fly, emerging from a "flax seed" through 

 base of leaf. Original. 



the same ground two years in succession where rotation is pos- 

 sible. Varieties of wheat that produce a stout stalk are the least 

 affected by this pest, and varieties of wheat should be selected and 

 the soil handled to that end, remembering that a rank growth 

 does not mean strong straw, but the contrary. 



5. Co-operation is absolutely necessary, for, however careful 

 one man may be, if his neighbor is not equally so the latter's 



