CATTLE AND HORSE PARASITES 439 



quently excavating a large cavity. The purulent discharge from 

 such sores attracts other flies to lay their eggs, more maggots enter 

 the wound, and unless aid is rendered the animal dies. A slight scratch 

 or merely a mass of blood from a crushed tick may serve as a starting- 

 point for the trouble. The flies also breed in decaying carcasses. 



Treatment. — Prevent the deposition of eggs by washing all wounds 

 as soon as noticed with a disinfectant, and then apply a dressing of 

 pine tar or tar and grease. When wounds are found infested, dislodge 

 the maggots by injections of carbolic acid diluted with 30 parts of 

 water, or one of the coal-tar sheep dips may be used. After the maggots 

 have been removed and the sore thoroughly disinfected, dress the 

 wound with a coating of pine tar. Deep sores should be packed with 

 sterilized absorbent cotton. 



By careful attention to the destruction of garbage, carcasses, and other 

 filth in which the maggots breed in enormous numbers, much loss may 

 be avoided. Carcasses left to decay exposed to the air about pastures 

 are constant sources of danger. 



Horse. Horse bot-fly {Gastrophilus equi). — The light yellow 

 eggs are glued to the hairs on the shoulders, forelegs, and under side 

 of the body by a brownish fly about three-fourths inch in length. 

 By licking these parts the egg-cap is removed and young maggots taken 

 into the mouth. On reaching the stomach they attach themselves 

 to the walls and remain there until the following spring. When abun- 

 dant they may nearly cover the whole inner surface of the stomach, 

 interfere with the secretion of the digestive juices, and by collecting 

 near the pyloric opening prevent the natural passage of the food from 

 the stomach. When mature they loosen their hold and are voided 

 with the excrement in late spring. These full-grown bots are 

 about three-fourths inch in length ; they burrow into the ground 

 where the pupal stage is passed. The flies emerge thuiy or forty 

 days later. 



Treatment. — Remove the eggs within a week after they have been 

 deposited by clipping the hair, or destroy them by washing with a solu- 

 tion of carbolic acid in 30 parts of warm water. When only a few 

 bots are present in the stomach, they do not seem to cause the animal 

 inconvenience ; when very abundant, they may cause fretting and 

 colic, and the horse may loose flesh. In such cases consult a veteri- 

 narian. 



