CHAPTER I 



INTRODUCTION 



AMONG the manifold operations of living creatures 

 few have more strongly impressed the casual observer 

 or more deeply interested the thoughtful student 

 than the transformations of insects. The schoolboy 

 watches the tiny green caterpillars hatched from 

 eggs laid on a cabbage leaf by the common white 

 butterfly, or maybe rears successfully a batch of 

 silkworms through the changes and chances of their 

 lives, while the naturalist questions yet again the 

 ' how ' and ' why ' of these common though wondrous 

 life-stories, as he seeks to trace their course more 

 fully than his predecessors knew. 



Everyone is familiar with the main facts of such 

 a life-story as that of a moth or butterfly. The form 

 of the adult insect (fig. 1 a) is dominated by the 

 wings two pairs of scaly wings, carried respectively 

 on the middle and hindmost of the three segments 

 that make up the thorax or central region of the 

 insect's body. Each of these three segments carries 

 a pair of legs. In front of the thorax is the head on 

 which the pair of long jointed feelers and the pair 

 c. i. 1 



