30 



CIECt'LAE 148, tr. S. DEPARTMENT of ageiccltttre 



Rocky Mountain States, but it is rapidly spreading in all directions. 

 The adult flies of this species deposit their eggs along the edge of 

 the lips and cause much annoyance to horses. The nose fly is the 

 most dangerous of the botflies and is the one which is responsible for 

 many accidents because its annoyance makes horses panicky and 

 causes them to run away. The bots of this species occur in the same 

 location as those of the chin fly. and when full grown also attach in 

 the rectum. 



Life history. — The eggs are glued to the hair of horses by the adult 

 flies. They hatch on the skin and the newly hatched maggots of 



FlGOlE 



!. — Portion or a horse's stomach, showing bots, GastrophUus inte&Hnalis, 



attached ro the inner linins: of the stomach wall. Natural size 



the common bot and of the nose bot are taken into the horse's mouth. 

 apparently while the animal is licking or biting itself. In the case 

 of the throat bot it has not yet been ascertained whether the maggot- 

 are taken into the mouth. Xor is it known whether the maggots 

 which are taken into the mouth are swallowed or whether they reach 

 the stomach in some other way. Once they get to the stomach, the 

 maggots attach themselves to its wall and remain there for a period 

 of from 8 to 12 months, during which time they attain their complete 

 larval development and then pass out of the body. While the com- 

 mon bot and the throat bot pass out of the body directly with the 



