PAIRING OF INSECTS, 217 



with a sort of tremulous quivering not very percep- 

 tible unless closely inspected. It might be that there 

 were no males in the vicinity, though the insect is 

 by no means rare around Lee ; at ail events, she re- 

 mained without a mate for about three weeks, as 

 the eggs which she at length laid proved to be in- 

 fertile, and she died soon after. In the instance 

 of a much rarer insect, the clear under-wing (JEgeria 

 asiliformis, STEPHENS), having discovered a brood 

 in the trunk of a poplar tree, we were desirous of 

 securing all that issued from it, and having caught a 

 female, we placed her in a box covered with gauze 

 at the root of the tree, the notion of surrounding 

 the tree itself with gauze not having occurred to us 

 at the moment. As this moth is one of the day- 

 fliers, we expected to make sure of all the males in 

 the neighbourhood ; but, to our no small disappoint- 

 ment, not one approached the box, though we after- 

 wards inclosed in it another female. This was the 

 more remarkable, that, from the protrusion of the 

 pupa cases from the tree, there was evidently not only 

 one or two, but a considerable number evolved after 

 the box had been placed there. In 1828, having 

 discovered a beautiful male crane-fly (Ctenophora 

 pectinicornis, MEIGEN), apparently just disclosed from 

 the pupa, we carefully examined the old willow stump 

 upon which it rested, expecting to find more of the 

 same brood. Next day we accordingly observed a 

 female, and imagining it to be one of the rare species 

 (Ct. ornata or Ct. jlaveolata), we placed her in a 

 gauze-covered box ; but no male approached for five 

 days, when a large hunting-spider found means to in- 

 troduce himself into the box, and make a meal of her *. 

 There is one extraordinary fact connected with this 

 subject, which is worthy of being prominently stated, 

 namely, that after insects pair, and the females de- 

 * J.R. 



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