30 THE entomologist's record. 



records its absence with a heavy heart, as if he hadn't been served 

 quite properly. But how many of our lepidopterists know that 

 probably a dozen specimens have never been captured in Britain out 

 of the New Forest. One or two odd specimens in Sussex and a few in 

 Devon are almost the only specimens that have been taken outside that 

 charmed circle in the New Forest. But strange to say the same facts 

 hold as we pass right through Central Europe, and through Central Asia. 

 In all the large wooded districts of this area brown and green females 

 occur {d/mi9r/)/n'c females, or females having two forms, as we term them). 

 In other more open areas north and south of this central area we find an 

 almost total absence of valeshia. It is absent in Scandinavia, Northern 

 Germany, Russia and Siberia, it occurs in Southern Germany, Armenia, 

 eastward into China ; but while throughout Central Europe and Asia 

 in the large forests the two forms of the female occur side by side, in 

 China the var. valesina appears to be the only form of the female 

 known. To the north-east of China in Japan the females are all brown 

 (somewhat darker than ours), but no valesina. Here then are some 

 strange facts. The more open northern districts in which paphia 

 occurs produce no valesina, the old wooded tracts of Central Europe 

 and Asia produce both brown females and valesina, but certain Chinese 

 districts produce valesina only. That more or less intermediate forms 

 should occur is only natural, and Mr. J. Jenner Weir possesses a series 

 of intermediate forms between the brown female and var. valesina taken 

 in the New Forest. That one of the forms, brown or green, was the 

 primitive form of the species is certain. Owing to the colour of the 

 male being brown, and the tendency in Rhopalocera to the production 

 of a more highly coloured male than female form, it would appear that 

 the brown female is the more highly specialised one, and that the green 

 {valesina) represents a more original form. There has been, no doubt, 

 therefore, a gradual displacement of the old by the new form which 

 has resulted in the general production of a brown female more closely 

 like the male, and this displacement is still going on. But the Chinese 

 females are all valesina. The condition therefore, in this district, must 

 have been more favourable to the preservation of the old form and less 

 favourable to the production of the new. 



I would now point out that the var. valesina is more particularly 

 attached throughout its entire range to wooded tracts, and it at once 

 suggests itself whether this form is not perpetuated in large forests and 

 wooded tracts, and more liable to displacement in small wooded tracts 

 and more open areas. If so, we should look, it appears to me, for the 

 cause of its origin or production in the excessive moisture of the woods 

 and forests rather than in any other direction. We so frequently get 

 erroneous ideas and vague generalisations of these dark forms being 

 remnants of an arctic fauna, that it is refreshing to find a species which 

 completely overthrows these false assertions. If it were a remnant of a 

 glacial or arctic form, we should not find all the females in the northern 

 range of the species brown, with the green form only in existence in 

 the woods and forests much farther south. 



That moisture directly influences the colour of Rhopalocera may be 

 gathered from the following : — " I lately met with a most interesting 

 experiment. Two totally different forms of an Indian butterfly have 

 been found to be a ' wet ' season and ' dry ' season form, and the wet 



