BOTS. 289 



shelP^ (male and female) says Mr. Clark, ^' tliey in a few 

 hours become dry, take wing, and tlien seek their mates. The 

 female being impregnated, searches for a proper subject 

 among the horses, performs with great solicitude and care 

 her office of depositing her eggs upon the legs of the horse, 

 in the manner we have already stated, thus completing the 

 wonderful round of its operations and history.'^ 



The insect of the cestrus hemorrhoidalis or funda- 

 ment EOT, whose manner of depositing eggs, says Mr. Clark, 

 has never been described, or known before, chooses the lips 

 of the horse for this purpose, " which is very distressing to 

 the animal from the titillation it occasions ; for he imme- 

 diately after rubs his mouth against the ground or his fore 

 legs, or sometimes against a tree, with great emotion ; till 

 the animal at length, finding this mode of defence insuffi-^ 

 cient, enraged he quits the spot, and endeavours to avoid it 

 by galloping away to a distant part of the field ; and if the 

 fly still continue to follow and tease him, his last resource is 

 in the water, where the oestrus never is observed to pursue 

 him. These flies appear sometimes to hide themselves in the 

 grass, and as the horse stoops to graze they dart upon the 

 mouth or lips, and are always observed to poise themselves 

 during a few seconds in the air, while the e^^ is preparing 

 on the extended point of the abdomen. ^^ — '^ The larva or 

 grub of this species inhabits the stomach as the former, 

 generally adhering to the white lining, and is disposed pro- 

 miscuously in dense clusters after the same manner ; they 

 may, however, be distinguished from them by being in general 

 smaller ) longer in proportion to their bulk, and rounder ; and, 

 I have thought, of a duller red, or more inclining to a ivhite, 

 than those of the oestrus eqid, for they difl'er in appear- 

 ance in diff'erent subjects.^^ These bots quit their habi- 

 tation in the same season of the year, but are rendered 

 remarkable by their '^ sticking more or less within tlie verge 

 or opening of the anus, adhering to its soft lining, and pro- 

 ducing considerable irritation. Indeed, I once well re- 

 member,^^ continues Mr. Clark, ^' being on a tour of pleasure 

 in the Isle of Wight, and experiencing much annoyance from 



II. 19* 



