STRUCTURE AND DEVELOPMENT OF INSECTS. 



11 



A correct knowledge of the exact time and conditions 

 under which the transformations occur for each individual 



Fig. 3. — Incomplete jMetamorpliosis of a Bug [Brachymena 4-jmsiic- 

 lata). a, eggs: 6, adult bug; c, different stages of young bugs 

 or nympLs. (Original.) 



insect pest is therefore often most essential when seeking 

 means for its control. 



How Insects Feed. 



The material to he used in cumhating a given insect is 

 almost entirely dependent upon the structure of its mouth- 



