called Oistros by the Ancients. 287 



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 invisi- 

 ble attack : the animals carried their heads aloft, their ears 

 pricked up and extended, beating the ground, and kicking in 

 the air with their feet, as though by enchantment. Then for 

 a while they would be quiet ; then, again, they were seen most 

 furious, and this with so general and regular a movement, that 

 no army would have surpassed their exercises in uniformity." 



Linnaeus further states, in the Lachesis Lapponica, respect- 

 ing the effects produced by this sort of (Estrus, that in passing 

 afterwards into the Lapland alps he observed a Rein-deer, 

 which was loaded with his own package, frequently to stop 

 short and become perfectly quiet and motionless as a pillar of 

 stone, or one suddenly struck with catalepsy ; the head held 

 straight out, the ears upright, the eyes fixed ; nor could he by 

 any ill treatment be induced to proceed ; but in a little while 

 he would again resume his march. Where, I would ask, is 

 the Tabanus, or Conops, that could produce effects like these ? 

 or what naturalist, at all acquainted with the operations of 

 Nature herself, could confound the dissimilar effects produced 

 by these several insects ? 



Linnaeus further says, that in the Rein-deer fly he saw the 

 egg held out " like a white mustard-seed" at the end of the 

 abdomen, which, if true, fully confirms the supposition that 

 there can be no infliction. 



The (Est? us hcemorrhoidalis and (Estrus Ovis, in performing 

 their office of ovi-deposit, are also equally irritating and pecu- 

 liar, as I have shown in the paper above alluded to, in the 3rd 

 volume of the Society's Transactions. 



I avail myself of this opportunity in conclusion, to state, in 

 addition to my former remarks on this genus, that it appears 

 to me, as there is no aculeus or weapon of infliction at the end 

 of the abdomen of the female of the (Estrus Bovis, that the egg 

 is simply thrust down among the hair, till it meets the skin, 

 and that then it is affixed to it by a glutinous liquor secreted 

 at the same time ; and that the egg being hatched, the young 

 grub insinuates itself into, and finally through the skin, form- 

 ing an abscess beneath it. In a somewhat similar manner it 

 is that the ichneumon flies deposit their eggs on the sides of 

 living caterpillars of the Lepidoptera, and hatching, perforate 

 their skins, and entering within, live on the parenchyma or 

 pulp of their bodies till matured and fully grown, when they 

 make their way out again and change to the chrysalis. 



I may also remark of the (Estri, that they appear to be 



wonderfully 



