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sequently through other causes the relative numbers of the 

 two forms became reversed, then B would cease to mimic A, 

 and provided always that the necessary variations arose, A 

 would begin to mimic B. The resulting interchange of 

 characters is what I should call Alternating Mimicry.* Let 

 us now examine what Dr. Dixey has actually said with regard 

 to the nature of the mimetic approach in the case of his 

 Reciprocal Mimicry. In Tr. Ent. Soc. 1894, p. 297, he defines 

 Reciprocal Mimicry as being produced by ' A and B con- 

 verging to a point between them,' and further on the same 

 page describes the process as ' mutual convergence ' (the italics 

 are his). On p. 298, foot-note, he points out specially that he 

 does not use ' convergence ' in Professor Poulton's sense, 

 namely, as signifying the assimilation of one form to another, 



[Ixxii 

 but as meaning 'the mutual ' approach by two forms to a 

 mean between them.' In Tr. Ent. Soc. 1896, p. 74, he refers 

 to his conception as ' a kind of give-and-take arrangement, in 

 consequence of which two or more inedible forms may hasten 

 the assimilative process by imitating each other ; ' and of 

 course such hastening can only take place when the approach 

 is simultaneous. In Tr. Ent. Soc. 1897, p. 324, we are informed 

 that ' the benefit of Miillerian Association being mutual, there 

 is a distinct reason . . . for the model to help on the pi'ocess 

 of assimilation by itself advancing to meet the mimic * (the 

 italics are mine). But in order that there may be no 

 possibility of a misapprehension Dr. Dixey in the same paper 

 (p. 328) gives a very precise definition as to what we are to 

 undex^stand when he uses his term Reciprocal Mimicry. This 

 expression, he says, ' is meant to convey, besides the general 

 idea of convergence, the special information that in the cases 

 to which the term is applied, the convergence is brought about 

 not hy the simple imitation of one form by another, but by the 

 interchange of features between forms and their consequent 

 simultaneous approach to an intermediate position ' (the 

 italics are mine). Now unless we are to interpret words in a 

 distorted sense, it seems to me that the above passages must 

 assuredly convey the definite idea that Reciprocal Mimicry 



* Strictly speaking, Diaposematism is a term more applicable to this 

 form of Mimicry than to Keciprocal Mimicry. 



