THE ANIMAL PARASITES OF CATTLE. 



499 



The fly also breeds in dead animals, and all carcasses should there- 

 fore be buried deeply or burned. 



Treatment for screw worms.— For proper treatment an animal suf- 

 fering from screw worms should be caught and thrown. Pour chloro- 

 form into the wound, taking care that it penetrates thoroughly into 

 all the burrows of the screw worms, if necessary using a slender stick 

 or a small bunch of twisted hay as a probe. The animal should be 

 held for several minutes in order to insure the continued action of 



Pig. 8. — The warble fly (Hypoderma lineata): a, adult female; 6, eggs attached to a hair, x 25; 

 c, larva as seen in egg; <i, larva from esophagus of an ox; e, next stage of larva from beneath 

 the skin of the back; /, larva at the stage when it leaves the back of cattle and falls to the 

 ground— all enlarged (after Riley). 



the chloroform. Finally the wound should be dressed with a car- 

 bolic or cresylic ointment to promote healing and thus prevent fur- 

 ther infection, or the wound may be painted with pine tar. 



Grubs, Wakbl.es, Bots. 



The common parasites known as grubs, warbles, bots, etc. (fig. 8), 

 found under the skin of the backs of cattle, where they form more or 

 less conspicuous lumps during the latter part of winter and spring, 



