384 THE ENTOMOLOGIST. 



however, I am correct in my supposition that the group spread 

 doivmvards, the single-brooded form of ^^ari/iewje wiU be the 

 older, and I take it that, when the evidently aggressive athalia 

 became separated from it, the parent stock was forced to extend 

 its southward range. Here it would be able to emerge earlier in 

 the year, and gradually a double-brooded habit might be formed; 

 as athalia advanced further south it would interfere less with 

 partJieuie, its single brood coming between the two broods of the 

 latter, though jjartlienie would still be urged further southward, 

 to a point to which athalia, with its still single-brooded habit, 

 has kot yet been able to follow it. It is significant that where 

 the two species are both common, the one is single- the other 

 double-brooded. Where both are single-brooded, ijarthcnie is 

 always scarce. The single-brooded habit of athalia may pro- 

 bably have been confirmed by the fact that its usual food-plant. 

 Scabious, does not provide food for the hybernated larva till 

 considerably later than that of j^arthcnie (plaintain). Deiouc, 

 in the form of herisalensis, on the other hand, I imagine 

 to have been evolved from parthenie much later, and when 

 and where its double-brooded habit was confirmed. The fact 

 that it has accustomed itself to a food-plant {Linaria) which, 

 so far as I am aware, parthenie never touches, would preclude 

 any considerable interference of the one with the other. With 

 regard to Caradja's theory that this species arose originally as a 

 hybrid between phoehe and either athalia or parthenie (' Iris,' vi. 

 p. 181), supported (?) by his statement that he has taken it 

 paired with each of the latter species, and possesses " undoubted" 

 hybrids, I would only remark that a few lines further on he 

 accounts for the darker athalia of the mountains as being 

 "doubtless" hybrids with parthenie, and that in most Pyrenean 

 localities ijarthenie and deione are by no means easy to distin- 

 guish, while in others the latter bears on the upper side a decided 

 resemblance to the athalia of the same localities. The strongest 

 argument for the close common origin of parthenie and aurelia 

 is the very striking resemblance of their larval and pupal stages, 

 though the ova are more easily distinguished. Of the origin of 

 dictynna I feel far more uncertain ; that its affinities are rather 

 with aurelia than with any other known species admits, I think, 

 of no doubt, and the aflinities of the Oriental plotina with both 

 add probability to the nearness of the relationship. Britomartis 

 may possibly be its immediate parent or its immediate descen- 

 dant. In the former case it has been almost completely ousted 

 by its descendant ; in the latter its double-brooded habit would 

 be a purely southern and comparatively modern development. 

 In ' Iris,' vol. xi. p. 9, Hormuzaki has a most interesting dis- 

 quisition on the phylogeny of dictynnoides, discussing the com- 

 parative possibilities of its being an ancestral or a modern form. 

 He also propounds the theory, which he seems disposed to 



