COLOUR IN LEPIDOPTERA. 23 



upperside is for the greater part of their life, deprived of 

 the action of light, as indeed of all those real sun-butter- 

 flies, that fly almost exclusively in the sunshine and even 

 then only for some hours, neither that the upperside of 

 the hindwings of many Heterocera, as Catocala and Ophi- 

 deres, as well as of several Sphmgidae, that is always 

 covered by the forewings in the day-time, is nevertheless 

 remarkably coloured. With regard to the pupae the in- 

 fluence of the light is of far greater significance, as has 

 been proved by many investigations. Yet it seems not to 

 be so much the action of light on the pupa itself as 

 indeed on the caterpillar a little while before it changes 

 into a pupa. But in this matter also one had better be 

 very cautious and not judge by a few single results, as 

 Mr. Bordage in his communications at the Cambridge Con- 

 gress *) clearly pointed out, and in the first place some 

 pupae formed in similar normal conditions ought to be 

 closely observed. I beg to refer once more to my study 

 on Pieridae (pages 174 — 175) and to what I said there 

 concerning varieties of Eugonia autumnaria Wemb. bred by 

 Merrifield. Of Papilio Memnon L. for instance there exist 

 bark-coloured ones mixed with some white and green, and 

 also wholly green pupae, the former perfectly rendering 

 the colour of the bark of a tree speckled here and there 

 with some green moss, and so resembling also the bran- 

 ches of the tree on which the caterpillar lives, the other 

 one resembling the citrus-leaves on which it feeds. Yet I 

 have often bred both forms under absolutely similar con- 

 ditions of light and environment. Just so with pupae of 

 other species. On Java I also happened to know the three 

 forms of pupae of Danais Chrysippus L., pale rose-coloured, 

 lively green and waxlike white ones, mentioned by Bor- 

 dage, but I also observed that part of those green pupae, 



1) B. Bordage. Experiences sur la relation qui existe entre la couleur du 

 milieu et la couleur des chrysalides de certains lépidoptères (Proceedings of 

 the fourth International Congress of Zoology. London, 1899). 



Notes from tlie Leyden Museiim, Vol. XXII. 



