INSECTS. 



Diamond Beetle. 



Caterpillar. 



1. The female of the GZstrus equi nearly double its natural size. 



3. The eggs, also magnified, deposited ou and adhering to the hair. 



3. The bots — one-half of their natur.-il size— adhering by their tentacula. en 

 hooked mouths, to the cuticular portion of the stomach. Some of them are 

 supposed to be recently detached, and the excavations which they bad made 

 in the cuticular coat are seen. 



4 The full-grown bot detached. 



6. The (Estrus ovis, or gad-fly of the sheep. 



Hercules Beetle. 



In two or three clays, these eggs are mature enough to he hatched. The horse, feeling some uneasiness 

 from this glutinous matter sticking upon the hair, licks the spot, and by the pressure, together with the 

 warmth and moisture of the tongue, the eggs are burst, and a small worm issues from each, which, adhering 

 to the tongue, is carried down into the stomach, and by means of a hook on each side of the mouth, fastens 

 itself to the insensible coat of that organ. Scooping out a little hole and plunging its muzzle into it, th^re 

 remains till the ensuing summer, feeding on the mucus and other matter belonging to tlio coats of ihe 

 stomach. 



It has now become an inch long, and proportionally large, and is ready to undergo its transformation. 

 It loosens its hold, falls into the digesting mass contained in the stomach, passes through the intestines, 

 and is discharged with the dung. It then speedily burrows in the ground, and so soon as a proper habita- 

 tion is hollowed out, a shelly envelopment gathers round it, and it appears as a pupa, or chrysalis. r 



Having remained here torpid, for a few weeks, it bursts from its prison, a perfect fly, identical with that 

 with which we began our description, seeks its mate, and having completed the act of fecundation, dies. 

 The female deposits her eggs and dies also. It is the larvae of this fly which is popularly called Bot. 

 The stomach of the horse is commonly covered with them. Ordinarily they do this animal no injury. 

 Occasionally they do harm, as when, by mistake they fasten on the upper part of the windpipe, thus pro- 

 ducing a cough beyond the alleviation of medicine, or get into the first intestine, and so irritate and choke 

 it as to destroy the horse. These, however, are mere exceptions. That a horse's stomach should contain 

 a large number of bots, is according to the order of nature, and if the animal be otherwise healthy, it is 

 very rare, that even their presence is known by any perceptible tokens. 



The Oestrus Ovis, or Gadfly of the Sheep, is -more formidable. It is smaller than the Oestrus of the 

 Horse, and its body is dark-brown, spotted with white. It is often seen in copses and on rails in the 

 vicinity of a copse. It abounds most in June and July, and is sometimes an intolerable nuisance in 

 woody regions. It is a great terror to the Sheep, the sight even of one throwing the whole flock into 

 commotion. 



The fly strives to reach the inner margin of the sheep's nostril, and darting upon it with lightning-speed, 

 deposits an egg. The moist warmth of the part soon hatches it, and a little worm escapes. This crea- 

 ture creeps up the passage and finds its way to some of the sinuses connected with the nose. The irrita- 

 tion caused by it, in crawling up the nose, would seem severe, since the sheep acts as though half-maddened. 

 Having reached some cavity near the root of the nose, the worm fastens itself to the membrane by its two 

 mouth-hooks, and these remain till the following April or May. There are rarely above three or four of 

 these bots in one sheep. 

 (359) 



