37 



animal from the excessive titillation it occasions, for he immediately after rubs his mouth 

 against the ground, his forefeet, or sometimes against a tree with great emotion, till find- 

 ing this mode of defence insufficient, he quits the spot in a rage, and endeavours to avoid 

 it by galloping away to a distant part of the field, and if the fly still continues to follow 

 and teaze him, his last resource is in the water, where the insect is never observed to pur- 

 sue him. These flies appear sometimes to hide themselves in the grass, and as the horse 

 stoops tofgraze they dart upon the mouth or lips, and are always observed to poise them- 

 themselves during a few seconds in the air, while the egg is prepared on the extended 

 point of the abdomen." 



Remedies. 



Mr. E. Verrill, from whose valuable paper on the external and internal parasites of 

 man and domestic animals, we quote, writes thus : — 



The amount of injury caused by the bots of horses has long been a matter of dispute, 

 many writers claiming that they are very injurious, and even at times fatal, while others 

 deny this and consider them as harmless, or even beneficial. This can be definitely settled 

 only by experiment, but most reasonable men would be content to forego any possiblebenefit 

 and be satisfied with a healthy horse, destitute of bots. No doubt many diseases due to other 

 causes are commonly attributed to these insects, but that they are frequently the cause of 

 serious trouble, is generally believed and admitted. In this instance prevention is com- 

 paratively easy, while all writers admit that there is no reliable cure, no matter how much 

 they may difiTer in other respects. The means of prevention consist chiefly in frequently 

 removing and destroying the eggs, and also in removing and destroying the full grown 

 larvae when observed attached to the rectum. The eggs being large can easily be seen, and 

 can be removed either by thorough washing and brushing, or by cutting the hairs off with 

 scissors. A wash of carbolic acid soap has been recommended to destroy them. In some 

 countries the grooms frequently wash out the mouths of the horses with a suitable brush 

 in order to remove the young larvae. Many drugs have been recommended to remove bots 

 from the stomach, but none that do not endanger the life of the horse can be relied on ; 

 and in cases where they bring away the larvse it is possible that those that are already in 

 the intestines are the only ones affected. Spirits or oil of turpentine is a remedy in com- 

 mon use, but should be used with caution, if at all. A better plan under ordinary circum- 

 stances is to keep the horses in good health in other respects, so that they can the better 

 sustain the attacks of the larvse, until they naturally pass away, which will usually take 

 place witjbout serious injury. In exceptional and severe cases only, resort should be had 

 to special medicines of a dangerous or doubtful character, and then they should be given 

 if possible in accordance with the advice of a competent physician. 



No. 2. — The Ox Bot-Fly {(Estnis bovis Latr.). 



This is a large and handsomely-col- 

 oured fly. 



M. Joly describes it as having a 

 very hairy body, a large head, the face 

 and forehead covered with light yellow 

 hair, the eyes brown and the antennae 

 black. The throat is yellow, barred with 

 black, the abdomen of a greyish white at 

 the base, covered with black hair on the 

 third segment, and the remainder of an 

 orange yellow ; the wings are smoky 

 brown. 



The fly appears during the summer 

 months, and the female lays her eggs on 

 the backs of cattle. There seems to be 

 a considerable difference of opinion as to 

 the manner in which the egg is deposited. 

 Mr. Bracey Clark holding very decidedly 



Fig. 29, The Bot Fly. (Estr us bovis. 



