26 



THE YOUNG NATURALIST. 



[Eebruary 



Habitat — Much more widely distributed in Britain than the last, 

 species but less so according to Drs. Staudinger and Wocke on the Con- 

 tinent of Europe where they give : — " Finland, Denmark, Middle and 

 Western Germany, and Hungary," only. It is, however found in 

 America, ("Entomologist's Monthly Magazine," Vol. XVIII., pp. 74, 

 75), and Dr. Jordan records it from Bergen in Norway ("Entomologist's 

 Monthly Magazine," Vol. XXIV., p. 128). Mr. Porritt's larvae came 

 from Scotland ("Entomologist's Monthly Magazine," Vol. XXII., p. 

 103) and it is included in Mr. Birchall's Irish list, (" Entomologist's 

 Monthly Magazine," Vol. III., p. 172), as occurring at Howth, and 

 Mr. Porritt writes that it is abundant at Askham, near York (in litt)' 

 I have taken it at Maidenhead in Berkshire, Deal and other 

 localities, in Kent, and in my own garden at Westcombe Park, quite 

 in the London District. 



A NOTE ON THE POSSIBLE ADVANTAGE OF 

 MELANIC VARIATION TO LEPIDOPTERA, 

 By Lord Walsingham, F.R.S., F.E.S.. &c. 



In an article in the " Young Naturalist " for this month, Mr. Dale 

 referring to the Presidential address to the Yorkshire Naturalist's 



Union, in 1885, writes — " Lord Walsingham argues that northern 



and mountain species of Lepidoptera are dark, because dark colours 

 absorb heat," and he proceeds, " Is such the case ? I say no !" From 

 what follows I gather that he does not dispute a tendency to darker 

 variation in northern Lepidoptera, which must be generally admitted, 

 but that he rather disputes the fact that dark colours absorb heat. I 

 doubt if Mr. Dale would be prepared to carry his theory into practice 

 by playing lawn-tennis in a black shirt, or getting under a black sun- 

 shade in summer. It has been frequently and conclusively proved by 

 experiment that dark surfaces do absorb and radiate heat more rapidly 

 than light surfaces. The simple experiment of placing pieces of black 

 and white paper, or cloth, on snow exposed to the sun, (I tried it with 

 the insects themselves) will show that the black melts the snow beneath 

 it, and sinks into it with more rapidity than the white. The instances 



