.. 



o8 Mr. Clark'j Obfervatiom on the Genus Oe/rrus, 



occafion the horfe to lick himfelf in thofe parts, and thus receive 

 the larva on the tongue and lips ; and a horfe that has had no ova 

 depofited on him, may yet have the bots by performing the friendly 

 office of licking another horfe that has. The eggs on the fhoulder 

 are particularly well difpofed for being received in this way. 



Whether theie larva; can exift in the ftomach of a carnivorous 

 animal I am not certain. I gave upwards of a hundred eggs (proved 

 by trials to be ripe, and containing a living caterpillar) to a cat in 

 milk, at various times; and on deftroying her at the end of two 

 months after the firft portion had been given, no traces of them 

 in the ftomach or inteflines could be difcovered. 



The fmall end of the chry[alis, in all the fpecies of this genus, 

 contains the head of the fly 5 the contrary being the cafe with almoft 

 all other infects. 

 • 



Of the Oestrus hamorrhoidalis: 



The larva of this infect, needs not to be particularly defcribed, as 

 it refembles in almoft every refpect that of the CE, EquL Its habits 

 are the fame, being feen in the ftomach of the horfe occupying the 

 fame fituation as thofe of the CE. JLqui, from which they can only be 

 diftinguifhed by their fmaller fize and greater whitenefs. See fig. 10. 



On difleclion it is found to poflefs fimilar air tubes and alimen- 

 tary canal. When it is ripe, and has pafTed through the inteftines, 

 its fkin becomes of a greemih-red hue. It generally afTumes the 

 chry falls ftate in about two days after leaving the reBlum^ and is then 

 of a deep-red colour. See fig. n. 



The larva of this and the preceding fpecies may be obtained from 



the horfe from the beginning of June to the middle of July, being 



found hanging to the extremity of the return. None of thefe larva 



i ever 



