called Oistros by the Ancients. 407 
able to account for this extraordinary agitation, I had formerly 
given way to the notion of some very painful infliction by the 
Œstrus : but I am now led to question this opinion, inasmuch 
as I can discover no instrument by which this effect can be pro- 
duced. ‘The shrill sharp sound, which Virgil describes, was, I 
dare say, not stated without some real ground ; and a friend of 
mine actually informed me, that he was standing in a farm-yard 
one day near some cattle, when one of these flies entered and 
approached them, and that he distinctly heard this shrill sound. 
In confirmation of this account we may remark, that the wing- 
scale, covering the halteres, which has been supposed by Keller 
to be the organ of sound, is particularly large in this insect ; 
but further than this we dare not assert, but leave the point 
for future investigation. We know from Linnæuss own ac- 
count, that the Œstrus Tarandi, or Rein-deer Bot, very simi- 
. lar in all respects to the Œ. Bovis, makes no sound while de- 
positing its egg ; which again brings me into doubt upon this 
matter. 
We next have to observe, in confirmation of the peculiar 
effects of these insects upon the animals they infest, that those 
of the Œstrus of the Rein-deer, are equally singular and re- 
markable; and this fact we have from the indefatigable re- 
searches of our immortal leader, Linnæus himself. He says, 
speaking of the Œ. Tarandi, in his Lapland Tour, that as he 
was in bed early one morning, he perceived a very ungrateful 
smell, and when day-light appeared, **there were standing about 
the cot a thousand of these Rein-deer, driven by old men, boys, 
dogs, and women, who milked these animals. They appeared 
to be under the apprehension of some invisible attack : the ani- 
mals carried their heads aloft, their ears pricked up and ex- 
tended, beating the ground, and kicking in the air with their 
VOL. XV. 3c feet 
