WARNING COLORATION 443 



the nest to found new colonies. The color which then 

 develops in the skin does not protect them against 4he 

 attacks of enemies, but it does appear to screen the inter- 

 nal organs against sunburn or the injurious effects of 

 light. Tan is a temporary protective coat, and the brown 

 and yellow pigments which are permanent features of 

 the skin of various races of men are protective adapta- 

 tions of the same character. In several species of animals 

 the nerves are more or less covered with pigment, while 

 in others a heavy pigmented coat lines the visceral cavity. 

 In many otherwise transparent marine organisms the 

 eyes, and, in certain species, the reproductive organs as 

 well, are coated with variously colored substances. In 

 these and many other species, it is assumed that color 

 screens are protective, or in certain instances they may 

 absorb or reflect the light and thus keep an animal 

 warm or cool. 



Warning Coloration. — Many animals are so bril- 

 liantly and conspicuously colored that it appears surpris- 

 ing that they have escaped annihilation on the part of 

 numerous enemies. The explanation, at least in certain 

 definitely established instances, is that the color adver- 

 tises the fact that they are dangerous on account of stings, 

 poisons, or a nauseous flavor. For example, there is a 

 gorgeously blue and red frog in Nicaragua which flaunts 

 its colors in the brilliant sunshine comparatively safe 

 from attack. Mr. Belt, who conducted the experiment, 

 states that he offered one of these frogs to ducks and 

 chickens, all of which refused it except one young duck 

 which snatched it up, promptly dropped it, " and went 

 about jerking its head as if trying to throw off some un- 

 pleasant taste." It has further been shown that the 

 memory of such experiences endures for a very consider- 

 able period, and the victims cannot be induced to repeat 

 the experiment. 



The yellow and black banded bodies of hornets and 

 wasps are also warning or signalling colors, reminding 



