328 Dr. Frederick A. DIxey on 



legitimately employed to designate the adoption of any 

 new features borrowed from another species. In so far as 

 A copies the appearance of B, it may properly be said to 

 " mimic " the latter, whether the object be to suggest 

 the presence of a disagreeable flavour which it does not 

 really possess, or merely to convey the impression 

 that it and its model are alike in all respects. Mdl- 

 lerian assimilation may be quite as deceptive as Batesian, 

 in the sense of leading to confusion between species 

 essentially distinct ; and in the case of a " weak " species 

 being associated with a "strong '^ one, the departure of 

 a form from the typical aspect of its congeners by the 

 development of strictly imitative features may be as well 

 marked in the one kind of mimicry as in the other. But 

 although either of the terms " Mlillerian mimicry " or 

 '' convergence " would appear to express quite adequately 

 the general idea of the mimetic relation between inedible 

 species, a separate terra is wanted to designate the 

 peculiar give-and-take changes which we have seen are 

 theoretically possible to a greater or less extent in every 

 case of Mlillerian association, and which in fact do actually 

 occur in several. It is to supply this want of a term that 

 I have proposed the expression " reciprocal mimicry,"* 

 which 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 by 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 foregoing remarks will, I think, have made it 

 sufficiently clear, (1) that reciprocal mimicry can only take 

 place in Mlillerian associations, not in Batesian ; and that 

 it is therefore, as I have elsewhere said " good evidence 

 of the distastefulness of all the forms between which it 

 can be shown to occur ; '' (2) that although a mimic 

 which is of relatively plentiful occurrence must be Mlil- 

 lerian, it does not follow that a mimic which is scarce 

 must necessarily be Batesian. An inedible mimic may 

 be either rare or common ; an edible mimic must be rare. 

 Judging by these principles, we must conclude that the 

 association of Pieris locusta $ with Reliconius cydno is 



* Trans. Eut. Soc. Lond. 1894, p. 298. 



