276 



THE YOUNG NATUEALIST. 



added to the list. It must always be a pleasure to the amateur entomologists 

 to increase the known fauna of a district, but there are few men who can and 

 fewer who will isolate themselves from the world in a far off island for a 

 whole summer, where the wants of civilized life cannot well be supplied. 

 And we who stop at home at ease or at most run off by cheap excursion trips 

 once a year, look very small on our return, and we owe to such men a deep 

 debt of gratitude not only for their self-sacrifice, but for the liberality they 

 invariably shew to their less energetic or less fortunate friends. 



With these two lists before us if we carefully read over Mr. Weir's obser- 

 vations, I think we may fairly draw very different conclusions as to the 

 causes of variation in lepidoptera to any given by Lord Walsingham in his 

 careful and interesting address to the " Yorkshire Naturalists' Union/' at 

 Doncaster, 1885, a copy of which has recently been lent to me by my friend 

 Dr. Ellis. Many years ago a very facile writer but empirical entomologist 

 exhibited a box of dark varieties of lepidoptera at a meeting of the " Northern 

 Entomological Society/' observing that northern insects tended to melanism. 

 It was asked by a practical member where did his North began, and this 

 rather posed him, bat to illustrate North and South a member brought blacker 

 darker specimens taken in Cheshire and Staffordshire (south of the meeting), 

 than any he exhibited, except only oculta, and we heard no more of geogra- 

 phical variation, it being generally conceded at that meeting that in so small, 

 so temperate, and so central a latitude as from 50° to 60°, little variation 

 could be expected geographically, but that geologically every variation might 

 be hoped for. Here we have in the observations on the Hoy insects 

 much that goes to show variation is far more the result of the geology 

 of the district than of isolation, climatic conditions, &c. ; but his 

 Lordship successfully clears the last assumption away as he does others most 

 logically. I confess I was surprised when I read at page 21 that the smoke 

 of our furnaces and our chimneys /tad given us dark Amphydasis betularia, 

 black varieties of grossulariata, c/d, suffusa, and dark Tephrosia crepuscularia 

 and liundularia, because the first and second black betularia taken were 

 found at rest upon trees in Cheshire where there is no smoke, and the blackest 

 grossulariata I breed are taken on Pen-y-guriawin (the white mountain) in 

 Wales, and the darkest Uundularia and repandaria. &c, I ever see are taken 

 at Delemere Forest, 12 miles from any smoke of moment, and at Burnt Wood 

 (Staffordshire), many miles away from the potteries and the iron- works of 

 that county. It is not my province to combat Lord Walsingham's paper, but 

 I think it quite within our right to suggest to our theorisers that they are 

 off the line, and to point out as practical workers that as in the case of Hoy 

 lepidoptera (they are bred on old red sandstone formation, and here we are 



