PROTECTIVE MIMICRY 233 



I have recently heard the objection raised to the 

 theory of Mimicry, that non-mimetic Pieridce, with 

 the typical appearance of their group, are among the 

 commonest butterflies in South America. It is there- 

 fore argued that the Pieridce are quite able to take 

 care of themselves, and, if any of them resemble 

 other forms, it cannot be in order to shelter them- 

 selves under the reputation of the latter. There 

 does not seem to be much force in this objection ; the 

 forces which tend to the extermination of a species 

 are so nicely balanced against the forces by which 

 its existence is maintained, that a very minute and 

 often quite inappreciable difference may lead to pre- 

 dominance or to scarcity, perhaps ending in exter- 

 mination. Because the typical Pieridce in South 

 America appear to be predominant, it by no means 

 follows that all the species of this group have always 

 been so. Furthermore, the fact that all mimicking 

 Pieridce are scarce, and that they invariably resemble 

 the butterflies of specially protected groups which are 

 also mimicked by other butterflies and by moths, is 

 a practical and complete answer to the objection. 



Mimicry in Asiatic Butterflies 



In the Malayan islands and in India Mr. Wallace 1 

 found that the Danaidce are the chief models for 

 Mimicry, although certain Morphidce and one section 



1 Linn. Soc. Trans, vol. xxv. pp. 19-22. 



