9 6 



INSECTS 



cycle of any one kind. Crickets there are of many 

 sorts, and some of these are general feeders, eating 

 each other as freely as they do vegetation and other 

 things. The tree-crickets are more definitely predatory 

 in habits and feed largely upon plant lice; but they 

 also are too few and too slow in reproducing to be able 

 to exert a very important influence on the increase of 

 their prey. Furthermore, they are limited as to the 

 places which they inhabit, and no field crops of any 

 sort harbor them. 



FIG. 41. Stylops and its development: a, female in body of bee; b, same in 

 outline; c, d, male from above and side. 



In the order Coleoptera or beetles we have few 

 truly parasitic forms. We may for the present consider 

 the family Stylopidcz as true Coleoptera and these are 

 found in the abdomen of various insects, chiefly bees 

 and wasps although some Hemiptera and perhaps 

 other orders are also infested. But they are so very 

 rare that they exert little influence on the numbers 

 of the species which they infest. Their life history 

 and complicated metamorphoses are extremely inter- 

 esting, the female being wingless and living in the 

 abdominal cavity of its host, with the head projecting 



