INSECTS AND JtlKDS 



(a) The members of the first class are killed by internal 

 poisons. Since they eat away parts of the plant, they 



WHEAT PARTLY DESTROYED BY THE HESSIAN FLY. 



can be destroyed much as we destroy rats by putting 

 poison on a piece of bacon for them to eat. As the bacon 



is eaten, the poison enters 

 the rat's stomach along 

 VJ with it. So we spray 



^^ the leaves of plants with 



a liquid solution poison- 

 ous to insects ; then, as 

 a part of the leaf is con- 

 sumed by an insect, the 

 poison upon the leaf 

 likewise enters the body 

 of the pest and kills it. 



Two common inter- 

 nal insecticides (internal 

 poisons for killing in- 

 sects) are arsenate of 

 lead and Paris green. 



ANGOUMOIS GRAIN MOTHS AND GRAIN 

 WEEVILS. 



Above is the injured grain; below at the left 

 are the weevils ; at the right, the moths. 



