58 THE ENTOMOLOGIST. 



of the seasonal dresses of the type according to the local climate. 

 Also the facies of an aberration like f. inst. V. nrticce ab. luna 

 (cf. Entom. vol. xlii., p. 223) is no doubt " climatic," and could be 

 thought to appear in an isolated local group as the characteristic 

 feature. 



3. An exaggeration of the regular seasonal variation of 

 V. urticfB points to V. milherti in one direction (var. polaris), 

 and to V. io in the other (var. ichnusa, chinensis).* 



4. Though ocelliforniity in urticce appears to be bound up with 

 the markings and colours peculiar to V. io, such facial ioformity 

 in urtlca could not guarantee also specifical io-formity, inasmuch 

 as a particular kind of sexual affinity seems not to be necessarily 

 bound up with any particular kind of facies. t Therefore — in this 

 sense — io-form aberrations, local (climatic) and seasonal forms 

 of the present day, need not be otherwise than facially transitory 

 to V. io, and the same holds good as regards their possible future 

 development. 



Quite a different view spreads before us, however, if the 

 significance of facial io-formity in urticce is considered in reference 

 to the past history of the species. In that case all existing facts 

 induce the acceptance of Prof. Standfuss's theory put forward in 

 his ' Handbook of Palfearctic Butterflies,' that V. io branched 

 off from the ancestors of V. urticce under the influence of a 

 climatical rise in temperature. 



Prof. Standfuss's reasoning is based on analogies in the life- 

 histories of the two species, on comparison of the male ancillary 

 appendages, and on the fact that by exposing the pupae of V. io 



* If these two already ioform varieties were available for temperature 

 experiments in the pupal stage, the results in facial transition to V. io might 

 naturally be expected to be more complete than with pupae of typical urticce. 



f It might be supposed that the sexes of a brilliantly-coloured day-flying 

 species are attracted to each other mainly by the sense of sight, when sexual 

 affinity would be dependent on, or be at least much influenced by, a special 

 facies. But V. io, which, with its peculiar colour and markings that distinguish 

 it perfectly from every other butterfly-species, offers the best excuse for such a 

 supposition is just one of those VanessidaB which, being yearly single-brooded 

 — except, perhaps, in Northern Italj' — does not pair till after hybernation in 

 the spring of the year following its emergence, when, having enjoyed life all 

 the previous summer and autumn since July, it is naturally in a very sad con- 

 dition facially, being often even in rags. V. urticcB shares the same habit in 

 its autumn broods, which, emerging as late as October, have less chance than 

 V. io to get rid of their beauty before the next spring ; but, mostly, urticce 

 also is badly damaged facially at the very time of its life when it must provide 

 anew for the future of the species. With all the other Vanessidie — which 

 are among our most richly-coloured flies — the case is similar. This perhaps 

 is conclusive proof that the colours and markings of the facies can have 

 little influence on sexual affinity in these butterflies. I even believe that if 

 a female F. io were artificially painted white or yellow, she would still be 

 sought out by the males of the species. 



In the case of moths it is perhaps well known that the wings of the 

 females may generally be entirely cut off without lessening their marvellous 

 attractive powers for the males or their fertility. 



