350 TROPICAL NATURE Vv 
flies, so that it is really a living trap, and forms its own 
bait !1 
All who have observed animals, and especially insects, in 
their native haunts and attitudes, can understand how it is 
that an insect which in a cabinet looks exceedingly con- 
spicuous, may yet when alive, in its peculiar attitude of 
repose and with its habitual surroundings, be perfectly well 
concealed. We can hardly ever tell by the mere inspection 
of an animal whether its colours are protective or not. No 
one would imagine the exquisitely beautiful caterpillar of the 
emperor-moth, which is green with pink star-like spots, to be 
protectively coloured; yet, when feeding on the heather, it 
so harmonises with the foliage and flowers as to be almost 
invisible. Every day fresh cases of protective colouring are 
being discovered, even in our own country; and it is becoming 
more and more evident that the need of protection has played 
a very important part in determining the actual coloration 
of animals. 
Warning Colours 
The second class—the warning colours—are exceedingly 
interesting, because the object and effect of these is, not to 
conceal the object, but to make it conspicuous. To these 
creatures it is useful to be seen and recognised ; the reason 
being that they have a means of defence which, if known, 
will prevent their enemies from attacking them, though it is 
generally not sufficient to save their lives if they are actually 
attacked. The best examples of these specially protected 
creatures consist of two extensive families of butterflies, the 
Danaide and Acreide, comprising many hundreds of species 
inhabiting the tropics of all parts of the world. These 
insects are generally large, are all conspicuously and often 
most gorgeously coloured, presenting almost every conceivable 
tint and pattern; they all fly slowly, and they never attempt 
to conceal themselves ; yet no bird, spider, lizard, or monkey 
(all of which eat other butterflies) ever devours them. The 
reason simply is that they are not fit to eat, their juices 
having a powerful odour and taste that is absolutely dis- 
gusting to all these animals. Now we see the reason of their 
1 These cases form a distinct sub-group of “alluring coloration.” See 
Darwinism, p. 210. 
