6180 



Insects. 



another species, CE. Bovis, respecting which, however, much difference 

 of opinion has arisen. At certain seasons, the whole terrified herd, 

 with their tails in the air, or turned upon their backs, or stiffly 

 stretched out in the direction of the spine, gallop about the pastures, 

 finding no rest till they also get into the water. This CEstrus is 

 asserted by some writers to make a strong humming noise, and hence 

 it has been supposed that the herd of cattle are alarmed at the noise ; 

 but this must surely be an incorrect conjecture, as the OEstri, if they 

 make any hum at all, are far outstripped in this respect by many other 

 insects which instil no dread into oxen. Neither are they alarmed in 

 consequence of being subjected to the same kind of attack upon so 

 sensitive a part as the lips, as is the case with the horses attacked by 

 the (Estrus hoemorrhoidalis. It is, however, asserted by some writers 

 that the dread is produced by the pain inflicted by the (Estrus in 

 depositing her eggs, her ovipositor being represented as constructed 

 like an auger or gimlet, only having several longer points it can wound 

 with more effect. When it is stated, however, that the QEstrus Bovis 

 does not occupy more than a few seconds in depositing each egg, 

 we may fairly doubt whether, with her long, fleshy tubular ovipositor, 

 she has been able to pierce the hide of an ox; or whether, as Mr. 

 Bracy Clark suggests, she only makes use of this long instrument to 

 thrust the egg down to the surface of the skin, which she does not 

 pierce, but only glues its eggs to it; the young larvae when hatched 

 burrowing into the flesh. If this be the case, the act of oviposition 

 must be unattended with pain, as in the case of the deposition of the 

 eggs of the (Estrus Equi ; and we must search for the cause of the 

 alarm of the herd, either in an instinctive knowledge that a certain 

 insect flying round them is the parent of a grub which at a future time 

 will be a torment to them, or in the attacks of some other insect ; and 

 I confess that I am inclined to consider that Virgil's beautiful descrip- 

 tion of the annoyance caused by 



' Myriads of insects flnttering in the gloom, 

 (CEstrus in Greece, Asilus named at Home), 

 Fierce and of cruel hum ' 



fly. Even though amongst a herd of perhaps five hundred rein deer there were not 

 above ten of these flies, every one of the herd trembled and kept pushing its neighbour 

 about. The fly meanwhile was trying every means to get at thera ; but it no sooner 

 touched any part of their bodies than they made an immediate effort to shake it off*. 

 In one respect this season is peculiarly propitious to the insect, as the reindeer's coat 

 is now very thin, most of the hair of last year's growth being fallen off." 



