48 



NATURE STUDY AND LIFE 



across the way, and soon he gives up the fight. We need 

 rather to study how to make the most of the far more 

 powerful and universal agencies of living nature, the 

 natural enemies of various insect species ; and with an 

 intelligent public educated about these problems and all 

 working together, many of the worst insect ravages may 



be easily and speedily 

 abated. 



First, as to a few 

 simple terms: By the life 

 history^ or the life story, 

 of an animal, we mean 

 all the changes it goes 

 through and all that it 

 does from the time it 

 hatches from the ^gg, or 

 is born, until it dies of 

 old age. Most insect 

 eggs hatch out into some- 

 thing quite unlike the 

 parent. This is called a 

 "larva." The larvae of 

 flies are often called " maggots," those of beetles, ''grubs," 

 and those of moths and butterflies, ''caterpillars." After 

 feeding actively and shedding its skin from five to twenty 

 times as it grows, the larva passes into its third stage, the 

 " pupa." To outward appearances this is a quiescent stage, 

 the insect being incased in a hard shell, but inwardly active 

 changes of form are going on. The pupa of a butterfly is 

 often called a "chrysalis," After the internal rearrange- 

 ments have been made and the proper time has arrived, the 



Fig. 13. Chrysalis of Cecropia in 

 Cocoon 



(i natural size) 



