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6o° centigrade ; when the same fragments were floated in a saucer
containing cold water they rapidly recovered their green colour,
which was even intensified.”—(Beddard. Animal Coloration, ft. 60.)
“ Mr. W. W. Smith has remarked that the prolonged drought
recently experienced in New Zealand produced pale-coloured varie
ties ; and that the Lepidoptera of that country are generally paler on
the plains than on the hills. ‘ The higher we ascend the Alps,’ he
remarks, ‘the more humidity we meet with, and the greater the
darkening of the Lepidoptera, until we reach the summit, when they
become perfectly black.’ ’’—(Beddard. Ibid. ft. 61.)
“ It is at least possible that the tawny colours of desert animals,
which have so often been brought forward as an instance of adapta
tion to the hues of their environment, may be due to a similar
cause.”—(Beddard. ft. 60.)
This possibility becomes a very strong probability when
we remember that dryness is the especial characteristic of
desert regions.
Exposure to, or protection from light, and change of
temperature, are also powerful transforming agents.
“ As a general rule those insects whose pupae are exposed are
brighter in colour than those insects whose pupae are concealed,
either in the ground or in a dense cocoon. Contrast, for instance,
the bright colours of the Vanessidae—the ‘ Red Admiral,’ the Peacock,
and others—whose chrysalids are naked and freely suspended with
the dull colours of most Satyrids which undergo their tranformation
in the ground. Similarly the Tiger-moths and the Crimson Under
wings contrast with the Cossidae and Agrotidae and most other
Noctuae ; and among the Geometers the bright yellow Swallowtail-
moth, Uraftteryx sambucaria, Angerona ftrwiaria, &c., may be
compared with the sombrely-coloured species of the genera Boarmia
and Biston.”—(Beddard. ftp. 62-3.)
“ Dorfmeister learns from his experiments that temperature exer
cises the greatest influence on the colour and marking of butterflies,
when it acts upon them during the change into the pupa, or shortly
afterwards. In many, a rise of temperature produces a lighter, more
brilliant, ground colour; a fall, a darker or less brilliant—for example,
Vanessa lo, Utricae. In Euprepia caja the red-yellow ground colour
of the posterior wings is changed by a rise of temperature into
vermilion red ; by a fall, into ochre-yellow.”—(Eimer. Organic
Evolution, p. 1 31.)