Warning Colouration 
armed and venomous, it is to its advantage that 
it should be recognised quickly, and so avoided 
by animals that might be disposed to take it as 
food. 
“Hence arises warning colouration, the ex- 
planation of which is due to Wallace. Darwin, 
who was unable to explain the reason for the 
gaudy colouration of some caterpillars, stated 
his difficulty to Wallace, and asked for sug- 
gestions. Wallace thought the matter over, 
considered all known cases, and then ventured to 
predict that birds and other enemies would be 
found to refuse such caterpillars if offered to 
them. This explanation, first applied to cater- 
pillars, soon extended to adult forms, not only of 
insects, but of other groups as well. . . . Insects 
afford many admirable examples of warning 
colours, and many well-known instances occur 
among butterflies. The best examples of these 
are found in three great families of butterflies— 
the Helzconide, found in South America, the 
Danaide, found in Asia and tropical regions 
generally, and the Acvezde of Africa. These 
have large but rather weak wings, and fly slowly. 
They are always very abundant, all have con- 
spicuous colours or markings, and often a peculiar 
form of flight, characters by which they can be 
recognised at a glance. The colours are nearly 
always the same on both upper and under sur- 
faces of the wings; they never try to conceal 
175 
