79 



of A. sagana, at one time considered a distinct species and 

 described as paulina, is dull greenish in ground colour, very con- 

 spicuously spotted, and banded with white. 



A. sagana and A. paphia both occur in Eastern Asia, but the 

 former would seem to be the commoner species. The form of 

 A. paphia {paphioides, Butler) occurring in Japan does not differ in 

 any material respect in the male from European examples of the 

 same sex, but the females are intermediate in colour between the 

 typical female of the species and var. valestna. In China both 

 for«is of the female of A. paphia are obtained, but it would seem 

 that valesina is the dominant form of this sex in that country. 



Looking, then, at the distribution of A. paphia, we might assume 

 that it is an older species than A. sagana, which only extends west- 

 ward to Siberia. We might also perhaps assume that valesina is the 

 oldest form of A. paphia, and should probably be within the realms 

 of reason if we ventured to regard the darkest examples of that form 

 as archaic, not only oi paphia, but of sagana. 



If we compare the lighter specimens of z/ij/w/;/^?' with itY(\2\Q A. sagana 

 we shall find that the pale markings on the fore-wings of the former 

 agree in position with the white marks of the latter, excepting as 

 regards the spot in the discoidal cell, but even this is represented 

 in a few examples of valesina. On the hind-wings, however, com- 

 parison must be confined to the outer marginal area, and here we 

 see that the white markings of sagana are represented in valesina 

 by pale ones. 



As a working hypothesis, let us suppose the ancestral form of 

 Argynnis, from which paphia and sagana have descended, to have 

 been something like the darkest example of valesina now extant j and 

 let us further suppose that we can, in imagination at least, follow the 

 process of evolution, which has resulted in the development of 

 sagana and what we call typical paphia. Among the various 

 modifications occurring in the specialisation of each there probably 

 was a stage when, in the male of sagana and both sexes oi paphia, 

 the typical colour of to-day began to appear. Possibly the pale 

 sub-apical dashes on fore- wings, and the pale patches in second 

 median interspace of hind wings, were the last to disappear, giving 

 place to the encroaching fulvous colour ; and it is perhaps to this 

 stage that the aberrant specimens under consideration have reverted. 



Of course it may be possible that these aberrant characters in paphia 

 are progressive rather than retrogressive ; but if this were so we 

 should hardly find them normally indicated in what is presumably 

 the older form of the female, /. e. valesina, and only rarely present in 

 what we have reason to believe is the newer form of that sex. 



Although I do not insist on the pale patches being ancestral 

 characters, I am inclined to consider that such a conclusion is not 

 altogether unsupported by the facts to which I have briefly adverted. 



