12 



INTRODUCTION. 



1. Chinch Bug. 

 Magnified. 



Insects which undegro such a marked series of 

 changes as those above described are said to have 

 complete transformations, to distinguish them from 

 those which do not undergo so 

 marked a series of changes — those 

 with incomplete transformations. In 

 one stage of existence — that of the 

 chrysalis or pupa — insects of the 

 first class take no food and are 

 unable to move about. With these, 

 also, the young or larva differs 

 greatly in form and appearance 

 from the adult. Thus, caterpillars 

 are very unlike the butterflies and 

 moths into which they develop, and larval honey 

 bees differ greatly from the adults ; but with the in- 

 sects of the second class this marked difference does 

 not exist.' The Chinch Bug furnishes a good illus- 

 tration of these transformations. The adult bug 

 (Fig. 1) deposits 

 eggs (Fig. 2. a, b) 

 about the roots 

 of g r a s s a n d 

 grain. From 

 these hate h 

 young bugs (c) 

 that do not dif- 

 fer in general 

 form from the 

 a i lulls. They suck the sap from various plants of 



Fig. 



m 



Chinch Bug: a, b, eggs: c, e, /, g, young 

 bugs, or nymphs. Magnified. 



