318 INSECTS ATTACKING STOCK AND POULTRY 



few days, when a horse has been exposed, with pure kerosene 

 might prove efficacious, but a mere combing or use of a brush 

 is not sufficient with this bot, or with any other laying eggs on 

 the hairs. Repulsive ointments on the lips or nose would be of 

 service where the animals are running in pasture. 



Ox Bot-Flies, Warble Flies. The genus Hypoderma includes 

 species of bot-flies which make tumors on cattle. Recent investiga- 

 tors question the accuracy of the following hitherto accepted method 

 of entering the animal. Like other bot-flies, they lay eggs on the 

 hairs in spring and summer, and these eggs are e'ther hatched by the 



FIG. 323. Red-tailed bot-fly. Greatly enlarged. (Lugger.) 



moist friction of the tongue of the animal the tiny maggots finding 

 their way into the mouth by subsequent licking or the eggs them- 

 selves are carried into the mouth and hatch there. In either 

 event, the young maggots migrate down the gullet, through its 

 walls and other tissues of the victim until they reach the skin, 

 where they appear, forming the swellings known as "warbles." 

 These become more noticeable in midwinter and later. Here 

 they mature, hi tumors caused by their own activities. Their 

 anterior end, with its mouth, is at the bottom of the tumor, where 

 the mucus upon which they feed gathers. The posterior end, 

 through which most of the breathing takes place, is directed up- 

 ward. This is near the small opening in the hide, which is appar- 



