286 Mr. Bracy Clark on the Insect 



toss of the head, perhaps, towards the part, if they sucked a 

 little too vigorously ; or, if they were still more importunate, 

 a lash of the tail, was in general all the notice he would con- 

 descend to take of them. But if an (Estrus approached, the 

 consternation was indescribable, and the agitation most re- 

 markable ; and the object attacked, however lazily he might 

 be disposed from the heat of the weather, or a full belly, would 

 become suddenly as agile as a young deer, and canter away, 

 holding out his tail, and running with a sort of undulatory 

 movement of the back (thereby endeavouring, perhaps, to dis- 

 appoint the touch and designs of his enemy), till he had ob- 

 tained his accustomed retreat in the water, or the fly had 

 quitted him, — 



Tossing the foam 



They scorn the keeper's voice, and scour the plain, 

 Through all the bright serenity of noon ; 

 While from their labouring breasts a hollow moan 

 Proceeding, runs, low-bellowing, round the hills. — Thomson. 



Assuredly no Tabanus can produce any effects like these. Un- 

 able to account for this extraordinary agitation, I had formerly 

 given way to the notion of some very painful infliction by the 

 (Estrus : but I am now led to question this opinion, inasmuch 

 as I can discover no instrument by which this effect can be 

 produced. 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 re- 

 mark, that the wing-scale, covering the halteres, which has 

 been supposed by Keller to be the organ of sound, is particu- 

 larly large in this insect; but further than this we dare not 

 assert, but leave the point for future investigation. We know 

 from Linnaeus's own account, that the (Estrus Tarandi, or 

 Rein-deer Bot, very similar in all respects to the (E. Bovis, 

 makes no sound while depositing 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 (Estrus of the Rein-deer, are equally singular and re- 

 markable ; and this fact we have from the indefatigable re- 

 searches of our immortal leader, Linnaeus himself. He says, 

 speaking of the (E. 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 



