INSECTS 



The blood-sucking flies are considered in another 

 chapter and have no important relation to other in- 

 sects, although some of the larvae, notably those of 

 the Tabanidce, or horse-flies, live to some extent on 

 other insect larvae inhabiting swampy and marshy 

 soil. The robber flies of the family Asilidce are veritable 

 falcons of the insect world and capture their prey by 

 pouncing upon it in flight, sucking its juices by means 

 of their powerful battery of lancets, and then discard- 

 ing the drv husk. They are not at all particular as to 

 what sort of species comes 

 into their way, — a fly, a bee, 

 a beetle or a butterfly, — any- 

 thing answers. And so while 

 they devour an enormous 

 number of specimens, they are 

 not specific checks to any line 

 of plant feeders. Indeed, as a 

 matter of fact the robber flies 

 do not discriminate in the 

 least: they will as cheerfully 

 devour a dragon fly or a 

 ground beetle as a butterfly or 

 June-bug; it is all a matter of which comes along first. 

 Among the bee-flies or Bombyliidcc, we find in the 

 larvae both parasitic and predatory types, and forms 

 which, like the blister beetles, devour the stored ma- 

 terial of bees and other species. The adult flies them- 

 selves are often bright colored and hairy, some of them 

 resembling bumble-bees in appearance and some with 

 long, bee-like mouth parts. In the larval stage some 

 are true parasites on caterpillars, notably cut- worms, 

 while others feed in the egg-pods of grasshoppers, 

 devouring all the eggs in a single pod in attaining full 

 growth. Those that feed on the stored food in bee 



Fig. 5 1 . — A robber fly, with larva 

 and pupa. 



