130 



THE YOUNG NATURALIST. 



increase in the nnmber of our birds, which has been going on since the 

 passing of the " Wild Birds Preservation Act." I do not know whether this 

 increase has been taking place everywhere, but it has been most marked here 

 (on the borders of Herefordshire and Worcestershire.) In support of the 

 assumption that it is chiefly our climate that is causing the number of our 

 butterflies to decrease, Mr. Eobson refers once more to the comparative table 

 of Palesearctic and British Lepidoptera, which table, he says, affords a strong 

 proof that such assumption is correct. Prom what I have already said it will 

 be evident that, in my opinion, far from affording strong, it does not even 

 afford evidence of any kind that such is the case. 



On p.p. 60-62 Mr. Eobson gives a list of the species of butterflies which 

 he thinks it most important to consider in connection with this question 

 at the head of his article, together with a number of interesting remarks. 

 This list and these remarks I have found of great assistance in enabling me 

 to give some idea of what I mean, when I say that man is the chief cause in 

 the diminution of our butterflies. Mr. Eobson divides the species into five 

 classes. As to two of these species, viz., II. and III., containing respectively 

 " Immigrants that do not breed here," and " Immigrants that breed here, 

 but seem unable to perpetuate their race," I have already sufficiently clearly 

 indicated my opinion that they have no real bearing upon the subject of the 

 present article, and I will consequently confine my attention to the other 

 three. 



I. Extinct (1.) 



In this class is one, and only one, species, and that this was destroyed by 

 man is, I think, abundantly clear. This species, Folyommatus Mppoi/ioe, 

 was, so far as we know, always a fen insect, and the chief (I do not know 

 whether they were the only) food plants of the larva were the dock and the 

 great water dock. The fen drainer consequently dealt this species a severe 

 blow, but it was left for the greed of collectors to give it the finishing touch. 

 Within the last twenty years, says Professor Westwood in an edition of his 

 British Butterflies, published 1860, "the insect has become common in 

 collections, owing to the immense number taken by collectors in the former 

 localities " [i.e. Cambridgeshire and Huntingdonshire) " which, together with 

 the drainage of the fens, as I understand has almost extirpated the species." 

 Since that time it has quite extirpated the species. The fen drainer, I take 

 it, restricted the range of the insect to a comparatively small space, and once 

 its range was so restricted it had no chance against the onslaught of greedy 

 collectors. Surely the hand of man is seen plain enough here. 



IY. Species that are Eapidly Disappearing. (3.) 



1 . LycjENA Acis.— This species, Mr. Eobson tells us, " has long been 



