46 NATURE STUDY AND LIFE 



On the side of injury and damage to man, it has been 

 calculated that insects about equally divide the produce 

 of the soil with the farmer. Professor Riley estimated 

 that insects destroy annually from |i300,ooo,ooo to ^oo,- 

 000,000 worth of produce in this country alone. These 



Fig. 10. Promethea just emerged 



figures were given twenty years ago and are low, as we 

 shall see, when we study the ravages of single insect 

 species. 



The beneficent work of insects consists in practically 

 creating by cross-pollination our beautiful and fragrant 



