11 H IHE entomologist's RECORb. 



to conform to these patterns must be variable, or, if there are constant 

 species that are conforming, they must have converged long ago when 

 they had not already become fixed. Mdinaca eijina must have drawn 

 JlrliamiKs silrana at a period long prior to any other attraction, as 

 JJ. .nlrana is a constant species, and must also be an old species from 

 the large extent of its range. It is also probably true for the same 

 reason that IJiliconius retiistits was attracted to M. nnwme much 

 earlier than was Hdiconius niunata. It is easy to see that once a 

 group, however small it may be to start with, has begun, it can go on 

 almost indefinitely. Arguing from an extension of this theory, it 

 would be (juite possible to imagine such a case as an ''all-palatable " 

 association, it would need only that a certain one of more species 

 should be exceedingly abundant and other species with an approxima- 

 tion of the same colouring to be much rarer. It would thus be not 

 iuiprobable that the very abundant species would act as a type, as 

 much of the attack out of curiosity would vanish, while the rarer 

 species, not being under constant observation, would certainly in all 

 probability be more readily persecuted. Having got thus far in the 

 argument, it is easy to refute the true Batesian theory of mimicry 

 altogether, which says that a palatable butterfly mimics a distasteful 

 one. Much more proof is needed of the palatability or otherwise of 

 various butterflies before one rejects the Batesian theory as unwork- 

 able in practice. It is of frequent occurrence to find that the so-called 

 palatable mimicker is far more abundant than the so-called mimicked 

 species. This would not, therefore, be of much, if any, advantage, to 

 the palatable species, especially if the coloration was not very 

 distinctive. If, however, both species (mimicker and mimicked) were 

 more or less distasteful, the benefit to the commoner would probably 

 be no less great than if it were a palatable species. It is agreed that 

 the attacks are mostly those made by young birds out of curiosity, and 

 the rare species would always be more of a curiosity than the common 

 one. There is plenty of evidence now that nauseous species are 

 attacked ; specimens that have notches taken out of both fore- or hind- 

 wing that coincide cannot have lost them by any ordinary wear and tear. 

 Once the association is formed and attained a fair size by a number 

 of species conforming to a certain pattern, the force acting to bring in 

 fresh members is considerable, and, if the various species fluctuate much 

 in numbers, the conformity will be all the greater and the equalising 

 force all the stronger, moreover, fresh arrivals would have a much 

 easier way of gaining protection by assimilation of colour. For this 

 reason it is explicable how, in a large group, no two members are 

 excessively alike, while, in small groups, where presumably one of the 

 species is always much more abundant, one finds often practically 

 complete assimilation. We know that, for the practical working of 

 the Mullerian theory, experimental attacks by the insect's enemies 

 must go on, and also be exceedingly numerous, as is now proved by 

 specimens being so often caught with notches snatched by birds from 

 i)oth fore- or both hindwings when at rest. We are in the habit of 

 assuming that the central or typical species is the most distasteful, 

 but is it necessary ? A species that was much more distasteful, but 

 not at all common, would be open for considerably more attack than 

 the abundant semi-distasteful species, because the notion of " out of 

 sight, out of mind," would come into operation. 



