216 HUXLEY AND NATURAL SELECTION 



enters into Miillerian association with a Danaine butterfly 

 even more distasteful to insect-eating animals. Bates 

 supposed that his mimics were hard-pressed forms which 

 managed to survive by their deceptive likeness to some 

 well-known, specially-protected, conspicuous, abundant 

 model. But misippus is an extraordinarily dominant 

 species : it may often be met with more abundantly than 

 its model. 1 Furthermore, the mimic has now succeeded 

 in establishing itself and lives without its model in several 

 places in the New World — Florida, certain West Indian 

 islands, Demerara, Brazil. This remarkable extension 

 of range is mainly due to its wonderful power of flight, 2 

 but also to the possession of qualities the very reverse 

 of those commonly supposed to be characteristic of 

 a Batesian mimic. The tropics of the New World are 

 inhabited by a community in which a feeble intruder is 

 by no means likely to hold its own. 



Furthermore, Hypolimnas misippus belongs to a genus 

 of which nearly all the species mimic Danaine butterflies 

 and yet none appear to be hard pressed in the struggle 

 for life. This is readily explicable if the whole genus 

 possesses distasteful qualities. The males when non- 

 mimetic, as in many of the forms, bear a marked likeness 

 to one another, whereas the mimetic females have been 

 modified in all kinds of directions by the mimicry of diverse 

 models. The remarkable species from Madagascar, 

 Hypolimnas dexithea, mimetic in neither sex, possesses 

 a pattern of the same general type as that of the non- 

 mimetic males of other species. There can be little doubt 

 that this is the ancestral appearance of the genus, and 

 that the females at one time possessed the pattern of their 

 non-mimetic males, to which indeed in many species they 

 commonly tend to revert in a greater or less degree. 

 Now this ancestral non-mimetic pattern is about as con- 

 spicuous as that of any known butterfly, — a black ground- 

 colour, with a large white patch in the centre of each wing, 



1 See Mr. C. A. Wiggins's and Mr. H. A. Byatt's observations in 

 Africa, Proc. Ent. Soc, Land., May 6, 1903, p. xxix. 



2 See Enl. Record, xii, Dec. 1900, p. 315, for the account of a swarm 

 encountered on the Atlantic 580 miles from the nearest South American 

 land, and 960 from the nearest African. 



