BODILY CHARACTERISTICS CONSPICUOUSNESS 311 



later that I had obtained new examples of that most curious case 

 of mimicry first detected (among Birds) by Mr. Wallace, where 

 an Oriole constantly derives protection from its foes by acquiring 

 the dress of a Bird always of the same powerful and gregarious 

 Honey -eaters. . . . When my collection was laid out for de- 

 scription by Dr. Sclater, the Oriole's and the Honey- eater's 

 dress were so strikingly similar that the sharp eye of that dis- 

 tinguished ornithologist was deceived, and the two birds were 

 described by him as the same species." 



Among Reptiles, Poisonous Snakes are so universally feared 

 by other animals that we should naturally expect them to be 

 mimicked by harmless forms. As in the case of Birds, the 

 imitation may be either of a general kind or carried out into 

 detail. The former is exemplified by a number of non-poisonous 

 Snakes which, when threatened or attacked, behave as if they 

 were venomous. The same thing is true for the harmless Blind- 

 worm, which is not a snake at all, but a snake-like Lizard. 



Probably the best example of Poisonous Serpents exhibiting 

 warning colours copied by innocuous species is afforded by the 

 Coral Snakes of South America and the West Indies (see p. 303). 

 Different species of these are copied with extreme accuracy 

 by harmless Snakes belonging to several genera, and a par- 

 ticular poisonous species may have more than one kind of 

 imitator. 



MIMICRY AMONG INSECTS. The phenomena of mimicry are 

 better illustrated by Insects than any other animals, and indeed 

 the matter was first placed on a scientific basis by the researches 

 of Bates upon the Butterflies of the Amazon valley. It will there- 

 fore be convenient to make Butterflies and Moths our point of 

 departure. There are three sub -families of the former which 

 have their head-quarters in the tropics, and are possessed of 

 properties which cause them to be avoided by insectivorous 

 animals. The technical names of these three groups are Danaids, 

 Acraeids, and Heliconids, the members of all three being distin- 

 guished by colours and patterns that are regarded as having a 

 warning meaning. 



Heliconids. This sub-family is limited to and very charac- 

 teristic of tropical America, and it is the one specially studied 

 by Bates as mentioned above. He showed that a considerable 

 number of the included species are copied in a very faithful 



