334 



TEXTBOOK OF ZOOLOGY 



ders; while Imms, the noted English entomologist, has included 

 twenty-three orders in his A General Textbook of Entomology. 



In this elementary consideration of insect classification we have 

 tried to include information and illustrations which will be of value 

 in interesting the student in the thousands of insects of our environ- 

 ment. 



Fig. 199. — Hymenoptera. Alfalfa-seed chalcis-fly, Brucophagus funetris How. 

 A, female; B, female antenna; C, male antenna; D, eggs (greatly enlarged) ; E, 

 anterior view of right mandible; F, larva; G, pupa, (enlarged) ; H, worker of the 

 black ant. (From Sorensen and Knowlton, permission Utah Agricultural Experi- 

 ment Station.) 



SOCIAL LIFE AMONG THE INSECTS 



The great majority of insects live an individual existence, with- 

 out any cooperation or filial relationship existing between parents 

 and offspring. The processes that have ever been operative have 

 emphasized the importance of the individual in the scheme of prog- 



