296 NORTH AMERICAN INSECTS. 



case, but, on the contraiy, as may be seen almost every day 

 in spring and the beginning of summer, the female of this 

 fly deposits her eggs, often five hundred in number, upon 

 the fore-legs of the horse. In about four days these eggs are 

 hatched ; and as by their motions they produce a tickling 

 or itching, the horse tries to remove them with his tongue, 

 and in doing so swallows most of them, by which means 

 they are transported to the stomach, where each one fastens 

 itself, by means of two horny hooks, to the internal coat, 

 there sucking its fleshy fibres and feeding on the gastric 

 juice. When full grown, and about three quarters of an 

 inch long, they leave this viscus, are carried along through 

 the intestines, and, with the balls of fecal matter, fall to 

 the ground, enter it, and transform themselves into pupag, 

 from which, after three or four weeks, they come out as 

 perfect flies. 



As each of these maggots, for its habitation, bores a cell 

 as large as a grain of Indian corn, and by this operation 

 causes more or less of irritation, often inflammation of the 

 stomach ; and as their number often amounts to many hun- 

 dreds, we may imagine that the consequences would be very 

 serious, as indeed they are, often causing fatal epidemic dis- 

 eases of horses. In such cases the animal loses his appe- 

 tite and flesh, is afliicted with cough, bites its sides, dis- 

 charges much phlegm from the nose, breathes with great dif- 

 ficulty, and will die unless remedies are successfully used to 

 expel these larvae, such as mild laxative oils, etc. 



But as the gad-fly that infests the horse is found only in 

 fields, bots are found only in such horses as feed in pas- 

 tures or work in the fields, and hence much may be done 

 in the way of preventing their ravages by currying and 

 cleaning the horse twice a day. 



Dr. Harris, in his work on Injurious Insects, mentions 

 also the Small Red-tailed Bot-fly {CEstrus hcemorrhoidalis), 

 which deposits her eggs on the lips, and the Brown Farrier 



