236 
DARWINISM 
CHAT. 
The most interesting and most conclusive example of 
warning coloration is, however, furnished by caterpillars, 
because in this case the facts have been carefully ascertained 
experimentally by competent observers. In the year 1866, 
when Mr. Darwin was collecting evidence as to the supposed 
effect of sexual selection in bringing about the brilliant 
coloration of the higher animals, he was struck by the fact 
that many caterpillars have brilliant and conspicuous colours, 
in the production of which sexual selection could have no 
place. We have numbers of such caterpillars in this country, 
and they are characterised not only by their gay colours but 
by not concealing themselves. Such are the mullein and the 
gooseberry caterpillars, the larvae of the spurge hawk-moth, of 
the buff-tip, and many others. Some of these caterpillars are 
wonderfully conspicuous, as in the case of that noticed by 
Mr. Bates in South America, which was four inches long, 
banded across with black and yellow, and with bright red 
head, legs, and tail. Hence it caught the eye of any one who 
passed by, even at the distance of many yards. 
Mr. Darwin asked me to try and suggest some explanation 
of this coloration; and, having been recently interested in 
the question of the warning coloration of butterflies, I 
suggested that this was probably a similar case,—that these 
conspicuous caterpillars were distasteful to birds and other 
insect-eating creatures, and that their bright non-protective 
colours and habit of exposing themselves to view, enabled 
their enemies to distinguish them at a glance from the edible 
kinds and thus learn not to touch them; for it must be 
remembered that the bodies of caterpillars while growing 
are so delicate, that a wound from a bird’s beak would be 
perhaps as fatal as if they were devoured. 1 At this time not 
a single experiment or observation had been made on the 
subject, but after I had brought the matter before the 
Entomological Society, two gentlemen, who kept birds and 
other tame animals, undertook to make experiments with a 
variety of caterpillars. 
Mr. Jenner Weir was the first to experiment with ten 
species of small birds in his aviary, and he found that none of 
them would eat the following smooth-skinned conspicuous cater- 
1 See Darwin’s Descent of Man, p. 325. 
