204 
DARWINISM 
CHAP. 
oil a plant with linear grass-like leaves and small blue flowers ; 
and Ave find the insect of the same green as the leaves, striped 
longitudinally in accordance with the linear leaves, and with 
the head blue corresponding both in size and colour with the 
fioAvers. Another species (Sphinx tersa) is represented feeding 
on a plant Avith small red fioAvers situated in the axils of the 
leaves; and the larva has a row of seven red spots, unequal 
in size, and corresponding A r ery closely Avith the colour and 
size of the fioAvers. Tavo other figures of sphinx larva? are 
very curious. That of Sphinx pampinatrix feeds on a AA’ild 
vine (Vitis indivisa), having green tendrils, and in this species 
the curved horn on the tail is green, and closely imitates in 
its curve the tip of the tendril. But in another species 
(Sphinx cranta), which feeds on the fox-grape (Vitis vulpina), 
the horn is very long and red, corresponding AA r ith the long red- 
tipped tendrils of the plant. Both these larva? are green with 
oblique stripes, to harmonise with the veined leaves of the 
vines ; but a figure is also given of the last-named species after 
it has done feeding, when it is of a decided broAvn colour and 
has entirely lost its horn. This is because it then descends to 
the ground to bury itself, and the green colour and red 
horn would be conspicuous and dangerous ; it therefore loses 
both at the last moult. Such a change of colour occurs in 
many species of caterpillars. Sometimes the change is seasonal; 
and, in those which hibernate with us, the colour of some 
species, which is broAvnish in autumn in adaptation to the 
fading foliage, becomes green in spring to harmonise with the 
neAvly-opened leaves at that season . 1 
Some of the most curious examples of minute imitation 
are afforded by the caterpillars of the geometer moths, Avhich 
are always broAvn or reddish, and resemble in form little 
tAvigs of the plant on which they feed. They have the habit, 
AAdien at rest, of standing out obliquely from the branch, to 
Avhich they hold on by their hind pair of prolegs or claspers, 
and remain motionless for hours. Speaking of these pro- 
tectiA r e resemblances Mr. Jenner Weir says: “After being 
thirty years an entomologist I Avas deceived myself, and took 
out my pruning scissors to cut from a plum tree a spur which 
I thought I had overlooked. This turned out to be the larva 
1 R. Meldola, iu Proc. Zool. Soc., 1873, p. 155. 
