284 Mr. Bracy Clark on the Insect 



description of the effects it produces upon cattle, and which 

 are so singular, that they have afforded incidents to most 

 rural poets, ancient and modern : and the truth seems to be, 

 that the poets in describing these effects have been true to 

 nature ; while the philosophers, being presented with a wrong 

 insect, have only involved the subject in error. 



That it is an Italian insect we have the authority of Valli- 

 sneri of Padua, who appears to have been the first naturalist 

 who bred the true (Estrus Bovis from the grubs found in the 

 backs of the cattle ; and for the first time, as far as we possess 

 any record of the subject, saw with certainty the identical ob- 

 ject that created so much commotion among them. He ap- 

 plied correctly enough the passages of the ancients which he 

 thought had allusion to this insect. Reaumur followed Valli- 

 sneri in these researches, and bred with great difficulty one 

 imperfect specimen of the true Oestrus Bovis. Linnaeus next 

 followed ; but not having ever seen the insect, and not daring 

 to describe from figures merely, or the descriptions of others, 

 he took the large Horse Bot for it, — -the CEstrus Equi of my 

 enumeration. This error is continued through all the editions 

 of the Systema Naturce, intending all the while, and referring 

 to Vallisneri and Reaumur for, the true CEstrus Bovis. Thus, 

 like some of the ancients, he also described a spotted-winged 

 insect for the (Estrus Bovis ,• whereas the true insect has per- 

 fectly spotless wings. The true fly cannot be caught in the 

 act of oviposition, from the violent running of the cattle, and 

 the terror they are in at the approach of their enemy. 



This makes it more than probable, nay, almost certain, that 

 if Aristotle, iElian or Pliny described an insect with spotted 

 wings, or with a trunk or proboscis, &c, they knew nothing 

 about the true CE. Bovis, and had been deceived as to the real 

 object of their research. It was indeed much more easy for 

 them to have been presented with one of the numerous host 

 of flies that infest the backs of cattle and lodge on them, than 

 the true CE. Bovis. Their fly may have been a Tabanus or an 

 Asilus, a Conops, or a Culex, or any other with spotted wings ; 

 for as the true fly cannot be caught in the act of oviposition, it 

 was next to impossible they should have discovered, or been 

 made acquainted with, the true object of such disturbance. 

 Indeed, during these commotions it would be dangerous to 

 approach the cattle, or to remove any thing from their back ; 

 and if an insect was caught under any other circumstance, 

 how could it be known that it was the genuine cause of this 

 agitation r 



It is in vain now to inquire what precise fly these ancient 

 philosophers might have been presented with, as their testi- 

 monies 



