ATTACUS ATLAS: A LIFE-HISTORY. 67 
In a case of variation of this kind it is natural to inquire how 
far the facts are in accordance with the theories of “selection ”’ 
and protective resemblance or mimicry, or more generally of 
“the adaptation of the organism to its environment.” An 
interesting question thus arises as to how far this difference in 
colour may be due to climate, height above sea-level, and more 
sombre colour of surrounding rocks. Thus we have Llanfair- 
fechan—a sheltered habitat; on the sea coast (which generally 
infers a more equable temperature during the year); and light- 
coloured rocks, producing a light bone-coloured type. And 
Bettws-y-coed—a habitat at a greater elevation—much subject to 
high winds, rain and chill misty days, and with rocks of a darker 
hue and somewhat shaded with dark rust-coloured grey, pro- 
ducing a darker form. 
Is the difference in these conditions sufficiently marked 
to account for a tendency towards Melanochroism? Or may 
we not conclude (from its greater pilosity and resemblance to 
an Arctic type) the darker variety to be the older or original 
type (possibly a survival from the Glacial period), and the light 
to be the aberrant form; and that the species originating inland 
and extending into a locality where the surroundings were of 
lighter hue, and which received a greater amount of sunshine 
throughout the year, accommodated itself to these new conditions, 
and gradually acquired, possibly for the sake of protection, the 
lighter tone of the rocks of its new locality ? 
Chatteris, January, 1879. 
ATTACUS ATLAS: A LIFE-HISTORY. 
By Paitie Henry Gosssz, F.R.S. 
(Concluded from p. 41.) 
Ir was now past the middle of September; the weather set in 
windy and cold; Thad not yet begun domestic fires; I therefore 
removed the whole ménage to an orchid-house, where there was 
a hot damp atmosphere, probably much like that of the Indian 
valleys whence the parents came. In one or other of my tropical 
plant-houses it remained thenceforth, save that, now and then, 
on a warm sunny day, when I wished to have the larvee under closer 
observation, I replaced it for a few hours in my study. 
