468 Transactions of the American Institute. 



Prof. Henry C. Colton — I have seen this worm frequently at this 

 season of the year. In some sections they are called " wolves." 

 The preventive is to rub the backs of cattle with some substance 

 which will keep off the gadfly in summer. It will not do to use car- 

 bolic acid where cattle can reach it with their tongues. I have seen 

 common pine tar and grease used with good effect. Mix it well and 

 rub it on the backs of the cattle. It is not likely to improve their 

 looks, but it will keep off the flies. 



Dr. J. V. C. Smith — Carbolic acid in its concentrated solution is 

 very dangerous. 1 paralyzed my hand for a week by merely dipping 

 it into the acid. I may add, rancid oil of any kind is good if put on 

 when these worms are in the flesh ; it will kill them by stopping the 

 spiracles through which they breathe. 



Mr. Henry Stewart — It will not do to kill them in the flesh. That 

 causes frightful and dangerous sores. They must be squeezed out. 

 Some kill by puncturing ; that is equally as bad as Dr. Smith's plan. 



Dr. Isaac Y. Trimble — Since there seems some confusion about 

 this matter it may be best to explain. The gadfly {oestrus hovis) is 

 peculiar to cattle, while the botfly {oestrus equi) pursues the horse. 

 The botfly is somewhat bee-shaped, while the gadfly is more like a 

 common fly greatly enlarged. The most, interesting circumstances 

 about these insects are their peculiar but diverse instincts. The bot- 

 fly will always deposit her eggs on such parts of a horse as will be 

 within reach of the tongue of the animal, and these eggs, either before 

 or soon after being hatched, will be licked off by the tongue, and by 

 that means finally reach the stomach, where the young feed till they 

 become full grown as grubs, and ultimately passing through the bowels 

 and falling to the ground with the droppings, where they undergo 

 their transformation to the fly or bee. These grubs have a curious 

 arrangement of hooks, by which they attach themselves to the folds 

 of the upper part of the stomach to prevent being prematurely car- 

 ried down. Their food is the contents of the stomach ; should this 

 become empty for some time they will feed upon the walls of the 

 stomach itself, causing pain, and sometimes death. In other words, 

 the horse dies of what is called bots. The treatment is to fill the 

 Btomach as soon as possible with something for them to eat — apples, 

 molasses and water, grass, if the horse is able to eat it. The gadfly, 

 on the contrary, deposits her eggs on those portions of cattle that 

 they cannot reach with their tongues ; otherwise the irritation arising 

 from the little punctures she makes, in which to deposit her eggs, 

 would cause the animal to lick the part, and that would be fatal to 



