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 Heliconidcz, found in South America, the 

 Danaidce, found in Asia and tropical regions 

 generally, and the Acrceidce 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 



