414 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



siini)ler our own existence would be if, during the Hrst half of our 

 life, we could earn and lay by a sufficient amount of money to be in- 

 dependent during the second half, when we could marry and raise 

 families without working at anything else, and without worrying 

 over the need of providing food, or paying the rent, or the mortgage. 

 Insects, in fact, have adopted many advanced ideas during their evo- 

 lution, and as a consequence they own the earth. The principle in- 

 convenience of tlieir double life is in getting from one stage into the 

 other. This involves a process of thorough reconstruction, or meta- 

 morphosis, during which the creature is helpless and assumes the 

 form known as the pupa. The subject of metamorphosis is one of 

 the most interesting phases in the study of insects, but metamorpho- 

 sis belongs to the postembryonic period of development and is, there- 

 fore, beyond the limits of our present theme. 



