224 



THE ABDOMEN AND ITS CONTENTS. 



there unsuspected until it weighed nearly half-a-pound, it then became entangled i& 

 the pyloric orifice, and prevented the passage of the food, and destroyed the horse.* 



BOTS. 



In the spring and early part of the summer, horses are much troubled by a grub 01 

 caterpillar, which crawls out of the anus, fastens itself under the tail, and seems to 

 cause a great deal of itching or uneasiness. Grooms are sometimes alarmed at tke 

 appearance of these insects. Their history is curious, and will dispel every feaj 

 with regard to them. We are indebted to Mr. Bracy Clark for almost all we kno\ 

 of the hot. 



CUT OF THE BOT. 



and 6 The eggs of the gad-fly, adhering to the hair of the horse 



c The appearance of the bots on the stomach, firmly adhering by their hooked months. 



The marks or depressions are seen which are left on the coat of the stomach 



when the bots are detached from their hold. 

 <v The bot detached. 



e The female of the gad-fly, of the horse, prepared to deposit her egg*. 

 / The gad-fly by which the red bots are produced. 

 g The smaller, or red bot. 



A species of gad-fly, e, the O3trus equi, is in the latter part of the summer exceed- 

 ingly busy about the horse. It is observed to be darting with great rapidity towards 

 the knees and sides of the animal. The females are depositing their eggs on thf 

 hair, and which adhere to it by means of a glutinous fluid with which they are su 

 rounded (a and 6). In a few days the eggs are ready to be hatched, and the slignx 

 est application of warmth and moisture will liberate the little animals which they 

 contain. The horse in licking himself touches the egg ; it bursts, and a small worm 

 escapes, which adheres to the tongue, and is conveyed with the food into the stomach. 

 There it clings to the cuticular portion of the stomach, c, by means of a hook on 

 either side of its mouth ; and its hold is so firm and so obstinate, that it must be 

 broken before it can be detached. It remains there feeding on the mucus of the sto- 

 mach during the whole of the winter, and until the end of the ensuing spring ; when, 

 having attained a considerable size, c?, and being destined to undergo a certain trans- 

 formation, it disengages itself from the cuticular coat, is carried into the villous por- 

 tion of the stomach with the food, passes out of it with the chyme, and is evacuated 

 with the dung. 



The larva or maggot seeks shelter in the ground, and buries itself there ; it con- 

 tracts in size, and becomes a chrysalis or grub, in which st:ite it lies inactive for * 

 feT* weeks, and then, bursting from its confinement, assumes the form of a fly. The 

 iemale, oecoming impregnated, quickly deposits her eggs on those parts of the hors 

 which he is most accustomed to lick, and thus the species is perpetuated. 



There are several plain conclusions to be drawn from this history. The bots can 



* The Veterinarian, vol. vii.. n. 7fi 



