368 ANIMAL STUDIES 



insects are known, but not many. The conspicuously 

 marked venomous coral-snake or coralillos (Elaps) is mim- 

 icked by certain non-venomous snakes called king-snakes 

 (Lampropeltis, Osceola). The pattern of red and black 

 bands surrounding the cylindrical body is perfectly imi- 

 tated. But whether this is true mimicry brought about 

 for purposes of protection may be doubted. Instances 

 among birds have been described, and a single case has 

 been recorded in the class of mammals. But it is among 

 the insects that the best attested instances occur. The 

 simple fact of the close resemblance of two widely related 

 animals can not be taken to prove the existence of mimicry. 

 Two animals may both come to resemble some particular 

 part in their common environment and thus to resemble 

 closely each other. Here we have simply two instances 

 of special protective resemblance, and not an instance of 

 mimicry. The student of zoology will do well to watch 

 sharply for examples of protective resemblance or mimicry, 

 for but few of the instances that undoubtedly exist are as 

 yet known. 



286. Protective resemblances and mimicry most common 

 among insects. The large majority of the preceding exam- 

 ples have been taken from among the insects. This is 

 explained by the fact that the phenomena of protective 

 resemblances and mimicry have been studied especially 

 among insects; the theory of mimicry was worked out 

 chiefly from the observation and study of the colors and 

 markings of insects and of the economy of insect life. 

 Why protective resemblances and mimicry among insects 

 have been chiefly studied is because these conditions are 

 specially common among insects. The great class Insecta 

 includes more than two thirds of all the known living 

 species of animals. The struggle for existence among the 

 insects is especially severe and bitter. All kinds of " shifts 

 for a living " are pushed to extremes ; and as insect colors 

 and patterns are especially varied and conspicuous, it i& 



