208 
DARWINISM 
CHAP. 
which has just that amount of irregular curvature that is seen 
in dry and withered leaves. The colour is very remarkable 
for its extreme amount of variability, from deep reddish-brown 
to olive or pale yellow, hardly two specimens being exactly 
alike, but all coming within the range of colour of leaves in 
various stages of decay. Still more curious is the fact that 
the paler wings, which imitate leaves most decayed, are 
usually covered with small black dots, often gathered into 
circular groups, and so exactly resembling the minute fungi 
on decaying leaves that it is hard at first to believe that the 
insects themselves are not attacked by some such fungus. 
The concealment produced by this wonderful imitation is 
most complete, and in Sumatra I have often seen one enter a 
bush and then disappear like magic. Once I was so fortunate 
as to see the exact spot on which the insect settled ; but even 
then I lost sight of it for some time, and only after a per¬ 
sistent search discovered that it was close before my eyes . 1 
Here we have a kind of imitation, which is very common in a 
less developed form, carried to extreme perfection, with the 
result that the species is very abundant over a considerable 
area of country. 
Protective Resemblance among Marine Animals. 
Among marine animals this form of protection is very 
common. Professor Moseley tells us that all the inhabitants 
of the Gulf-weed are most remarkably coloured, for purposes 
of protection and concealment, exactly like the weed itself. 
“ The shrimps and crabs which swarm in the weed are of 
exactly the same shade of yellow as the weed, and have white 
markings upon their bodies to represent the patches of Mem- 
branipora. The small fish, Antennarius, is in the same way 
weed-colour with white spots. Even a Planarian worm, which 
lives in the weed, is similarly yellow-coloured, and also a 
mollusc, Scyllaia pelagica.” The same writer tells us that “ a 
number of little crabs found clinging to the floats of the blue- 
shelled mollusc, Ianthina, were all coloured of a corresponding 
blue for concealment .” 2 
1 Wallace’s Malay Archipelago, vol. i. p. 204 (fifth edition, p. 130), with 
figure. 
2 Moseley’s Notes by a Naturalist on the Challenger. 
