336 THE PLACE OE MIMICRY 



resemblances to models will generally be found among 

 mimics with the hii;hest decree of special protection. 



It must be again pointed out, as it has been before 

 (see pp. 235-7), that these mimetic resemblances are in- 

 dependent of affinit)'. In large numbers, even of closely 

 related s|)ecies, it can be shown that mimetic likeness is 

 not ancestral, but has been superposed upon an earlier 

 pattern which was entirely different. 



4. TJic Limit to lilullcrian Unificatioji of ]]^anii}ii^ 

 Colours in (Diy Country. — The Miillerian principle of 

 unification of W'arninor Colours, as an aid in the education 

 of enemies, would seem to carry with it the implication 

 that the process will continue almost indefmitely until 

 the utniost possible simplification is attained. The facts 

 brouL^ht forward in the last Section mii-ht also be con- 

 sidered to support this conclusion. Nevertheless, there 

 can be little doubt that a limit is (|uickly reached, and that 

 henceforward the main change consists in detachino- the 

 mimics or even the central models, when by migration, or 

 spreading through increase of mmibers, they extend beyond 

 the influence of the original combination to which they 

 belonored and come within that of another. The trans- 

 ference would be, of course, more easily effected if the 

 pattern of the new combination resembled that of the old. 

 The Miillerian principle is reciprocal in its action, and 

 the crowd of mimics in a given combination — the less 

 perfect as well as the more perfect — all tend to keep the 

 central member or members stable. 



The tendencies of Miillerian Mimicry are best studied 

 in Africa, where the problem is far simpler than in South 

 America. The chief Ethiopian models, the Danai)u\ are 

 represented by conii)aratively few species, and of these 

 a high proportion form the centres of strong Miillerian 

 combinations. Thus on the East Coast, the common 

 conspicuous Danaines are Lininas chrysippus^ ^Iviauris 

 niavius (form do))iinica)ius\ A. ochlta, A. ccheria and 

 A. albiviaculata. The two last, entering into the closest 

 synaposematic relationship, forni the centre of one strong 

 combination, the first forms the centre of another, the 

 second of another, the third of a smaller and less well- 



