THE BOT-FLIES. 



635 



yellowisli, with brown nervures. Some of these insects were 

 hatchetl from larvae found attached to the pupae of hidybirds. 



The kirvas of these P'lies are found to feed on various 

 substances, some being believed to be parasitic on other larvae, 

 and others ha\ing been observed to feed on vegetable sub- 

 stances. For example, the larva of one species, Phora daucl, 



LXXVI 



1. Phora abdominalis. 2. Omithnmyia frinqillaria. a. Phora abdominnlis : head, 



side view. 6. Do., leg. c. Ornithoniyia t'ringillaria, leg. d. Do., maxilla. 



was seen to feed upon the interior of decaying radish-roots. 

 The larva is nearly cylindrical in shape, but is slightly nar- 

 rowed in front. The last segment of the body lias eiglit 

 radiating points, like those of the one or two larv« which have 

 been described, and there are also two spiracles on the same 

 segment. 



^VE now come to the small but important family of the 

 CEstridae, popularly known as Bot-Flies. In these insects the 



