336 THE PLACE OF MIMICRY 



resemblances to models will generally be found among 

 mimics with the highest degree 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 affinity. In large numbers, even of closely 

 related species, it can be shown that mimetic likeness is 

 not ancestral, but has been superposed upon an earlier 

 pattern which was entirely different. 



4. The Limit to Miillerian Unification of Warning 

 Colours in any Country. — The Miillerian principle of 

 unification of Warning Colours, as an aid in the education 

 of enemies, would seem to carry with it the implication 

 that the process will continue almost indefinitely until 

 the utmost possible simplification is attained. The facts 

 brought forward in the last Section might also be con- 

 sidered to support this conclusion. Nevertheless, there 

 can be little doubt that a limit is quickly reached, and that 

 henceforward the main change consists in detaching the 

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

 spreading through increase of numbers, they extend beyond 

 the influence of the original combination to which they 

 belonged 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 Danaini, are 

 represented by comparatively 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 Limnas chrysippus, Amauris 

 niavius (form dominicanus), A. ochlea, A. echeria and 

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

 synaposematic relationship, form 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- 



