xxii 



others it would be particularly acceptable. How few are there at this 

 moment who can distinguish the sexes of the nightingale, the robin, 

 the wren, the moorhen, or twenty other most familiar birds ! Is not 

 this knowledge worth acquiring ? 



There is yet another subject, the facts of which are familiar and in- 

 disputable, and the digest of facts and theories thereon have been 

 rarely attempted by our ornithologists,* while our entomologists, who 

 possess perfect means, attempt no explanation or investigation what- 

 ever. I allude to the local appearance, disappearance or apparent 

 extinction of particular species. 



In this island the bustard, the crane and the stork have become 

 extinct almost without a thought, without a lament ; while the kite, 

 formerly existing round London in great abundance, and valued as a 

 scavenger, has taken himself to the hills and is unknown near the towns. 

 But it is to entomologists I would especially appeal. Is it not worth 

 their while to inquire why Limenitis Sybilla has deserted Coombe 

 Wood ; why Vanessa C-album is extinct at Birch Wood ; why Poly- 

 ommatus Hippothoe has disappeared from the fens ; and what has 

 become of Lycaena Acis in Herefordshire, and Leucophasia Sinapis at 

 Daren th ? Again, why do Lycaena bcetica and Pieris Daplidice occa- 

 sionally visit our Kent and Sussex coasts, but never remain to breed ? 

 Where has Noctua subrosea secreted itself? Some of these questions 

 are answered without difficulty, such as that about the stork; but how 

 shall we account for the disappearance of Lycaena Acis, which at Leo- 

 minster in 1832 was certainly the most common of all the blues, and 

 which has never been persecuted. I am not aware that a single speci- 

 men has been seen in that locality for thirty years. Its food-plant 

 cannot have failed; its pupae cannot have been drowned, as water 

 never rests on the hill sides where the insect once abounded ; no fens 

 have been drained ; no common land enclosed ; no alteration has 

 taken place in the temperature. 



Let us still pursue Entomology and investigate the connection be- 

 tween cuckoo-bees and their hosts ; wondrous associations, and for 

 what purpose ? Where is the cut bono of this friendly compact ? Is the 

 number of bees diminished, their increase checked, and why should it 

 be checked ? Is the increase of bees too rapid, and is the cuckoo 



* T cannot forbear alluding to the laborious exertions of the late Mr. Strickland 

 in the dodo book to which I have already alluded; and also to those of the late Mr. 

 Wolley and Mr. Newton into the history of the northern penguin as instances. 



