cxl Journal of Proceedings.
Weismann's ' Theory of Descent,' it had occurred to him that
during the Glacial Period most mammalia and most birds were
white. Lord Walsingham had accepted that part of the argument, bat
pointed out—what he (Mr. Meldola) was quite unaware of at the time
—that similar views had been entertained as far back as 1846 by
Craven, a writer on sporting matters, who clearly put forth the idea that
the white colouring was to protect animals against climate.* The insects
of Alpine regions, however, were generally darker coloured than those
of more southern regions. To account for this, Lord Walsingham
extended to the insects the argument of protection against climate, point-
ing out that while white would be a protection for warm-blooded
animals which generated their own heat, insects required to take all
the advantages they could of the feeble solar radiation. Consequently it
would be of extreme advantage to the insects of an arctic climate
to be darker-coloured than insects of a warmer latitude. The same
cause explained the white colour of the mammalia and the melanism
of the insects. He thought the field of research opened up in this
pamphlet was a very important one, and likely to lead to valuable
results. He might, for instance, refer to the support which it afforded
to Weismann's speculations on the seasonal dimorphism of Lepi-
doptera.†
Mr. W. Cole pointed out that the average colour of insects which
appeared early in the Spring was very light, which was rather
an objection to this theory, because one would think it would be a
benefit to an insect in the early cold days of Spring to obtain as much
warmth as possible by absorption.
Mr. Meldola said he had foreseen this objection, but it was merely a
difference of degree of colouration where both forms were coloured, and
would probably not lead to any great difference of power of absorbing
heat. But in the case of such a well-known insect as Pieris napi, the
difference came out very strongly. There the winter Alpine form
(ab. bryoniae) was almost black, and the summer generations were very
light indeed.
Mr. Holmes remarked that the hair of the mammoth which was found
embedded in the ice at Siberia was of a dark colour.
Mr. Meldola said that in the case of the mammoth, the protection
seemed to have been afforded by the woolly covering.
Mr. White observed that the mammoth was an extinct animal, and
possibly its dark colour was one reason why it had died out.
The Rev. A. W. Rowe, M.A., F.G.S., then read a paper " On some
Crystalline Rocks from the Drift in the Neighbourhood of Felstead,
Essex," which was illustrated by a long series of specimens of the rocks
themselves, and some beautiful microscopical sections of the same.
* Recreations in Shooting,' p. 101.
† Mr. Meldola gave a summary of his observations in ' Nature' for April 2nd,
1885 (vol. xxxi., p. 505).