404 Mr. Bracy Crank on the Insect 
correctly enough the passages of the ancients which he thought 
had allusion to this insect. Reaumur followed Vallisneri in 
these researches, and bred with great difficulty one imperfect 
specimen. of the true Œstrus Bovis. Linnwus 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 Œstrus Equi of my enumeration; 
This error is continued through all the editions of the Systema 
Nature, intending all the while, and referring to Vallisneri and 
Reaumur for, the true Œstrus Bovis. "Thus, like some of the 
ancients, he also described a spotted-winged insect for the CEstrus 
Bovis; whereas the true insect has perfectly 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, Ælian or Pliny described an insect with spotted 
wings, or with a trunk or proboscis, &c., they knew nothing 
about the true Œ. 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 A silus, 
a Conops, or a Culez, 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 ? 
It is in vain now to inquire what precise fly these ancient phi- 
| losophers 
