390 



Hoiv Living Things Affect 072e Another unit vii 



Fig. 338 Ma?2y kinds of in- 

 sects injure trees. A piece of 

 bark has been raised to show 

 the timnels of the pine beetle. 

 The eggs are laid in tbein. 

 Why does this tiinneliiT^ in- 

 jure the tree? (u, s. forest 

 service) 



Fig. 339 The hmimn head 

 lotise. The lines are Iminan 

 hairs. Closely related species 

 attack dogs, goats, aiid other 

 animals, and do ?>mch harm. 



(U. S. BUREAU OF ENTO- 

 MOLOGY) 



Fig. 340 The boll weevil lays its eggs in a cot- 

 tonboll. See text, page 389. (u. s. bure.\u of 

 entomology) 



such insects are as important to them as 

 to the farmer. No matter where we hve 

 we all pay higher prices for many kinds 

 of foods because of insect damage. 



Most farmers know how this comes 

 about. The city boy or girl ought to 

 know, too, so that the farmer's problem 

 may be understood by all. The farmer 

 raises potatoes for sale in the market. 

 He puts in a certain amount of labor on 

 this acre of potatoes and spends money 

 for fertilizer, farm implements, and so 

 on. If the Colorado potato beetle injures 



