INSECT PARASITES AND PREDATORS OF INSECT PESTS 



19 



natural enemies of that insect. This bug is also known as an impor- 

 tant enemy of the European red mite (Paratetranychus pilosus C. 

 and F.) upon fruit trees, the common red spider {Tetranychus bi- 

 maculatus Harv.) on cotton, hops, and citrus, and of various species 

 of thrips. Aside from its insect-feeding habits it has been associated 

 with the transmission of certain diseases of corn. 



Various bugs may at times be found with the beak imbedded in the 

 body of a caterpillar, from which they suck out the body juices. Some 

 of these species confine themselves to insect food while others ma}^ 

 subsist upon a mixed diet of insect and plant juices. 



Figure 14. 



-Erax lateralis Macq.. a robber fly : A, 

 active larval form. 



Tbe adult fly ; B, tbe pupa ; C, tbe 



The robber flies (fig. 14), which belong to the family Asilidae, feed 

 very extensively upon a wide variety of insects. Many of them are 

 large, powerful flies, capable of capturing beetles, flies, and other 

 insects while in flight. After seizing their prey they insert the beak 

 into the body and suck out the juices. The larvae of these flies live 

 in the soil and feed upon white grubs and other soft-bodied insects. 

 In appearance the larvae have a considerable resemblance to the wire- 

 worms that feed upon the roots of plants. 



The praying mantids are large, conspicuous insects which attract 

 much attention because of the striking manner in which the front legs 

 are held while awaiting prey, The forelegs are long and armed with 



