35 



The progress of the said evolutional process may be studied extremely 

 well in this genus. From the general red original colour there remains only 

 one relict near the apex on the upper-side of the fore-wings ; in the $ this red 

 is attacked by a strong development of the black, while, in the meantime, it has 

 paled into white in some species without its being proved that here also yellow has 

 been the colour of a transition stage, so that in this respect, there may perhaps have 

 been an somewhat accelerated evolution. In this way it has happened with regard 

 to the 9 which occur in Morty island, belonging to the northern Moluccas, 

 in the Talaut islands, in Borneo (I. Borneensis Wall.) and in Bouru (I. Leuco- 

 GYNiA Wall.). Transitions which clearly prove this progress, are sometimes found. 

 I here give (pi. Ill fig. /) a figure of a § from the Kangean islands, east of 

 Madura, that belongs to the Pagenstecher collection, which shows only a 

 remnant of the said red ; I also saw such specimens from Celebes and Tonkin, 

 in Lombock also it is said that some are found. From Soumba I saw in 

 the Ch. Oberthur collection a $ in which this red had turned into pale orange, 

 and another 9, in which even of this orange only some indistinct traces were 

 visible. In the closely allied Genus of Pieridae Callosune Doubl. also, the 

 same spot is to be seen, too, turning paler into all kinds of shades, from 

 blood-red to pale yellow ; and in the well-known Euchloe (Antocharis) Car- 

 DAMiNEs L. this spot has turned into orange in the ^, but has already been 

 entirely replaced by white in the 9, which has proceeded further in this respect 

 as is also the case in the 9 of the Iphias species or races already mentioned. 



For the rest the colour on the upper-side has been turning paler into 

 yellow, which yellow has again turned into a paler shade and at last changed 

 into white, in which colour sometimes more, sometimes fewer traces of the 

 yellow have remained. In the form Roepstorffi Stdgr. there is still a good 

 deal of this yellow, in the Glaucippes from the Philippines, from Flores and 

 from Soumba the remnant of the yellow seems to have been piled up, as has 

 also happened with the red, to the apex of the forewing, forming there a 

 streak on the edge between the red which has remained there and the white 

 which has become the general colour; in the form Glaucippe from Java this 

 streak is also still visible, but has already become rather indistinct. All this 

 shows an extremely clear example of the gradual, as well as varying, progress 

 of the said evolution ; it may be that here and there local circumstances have 

 exercised some influence, but it would certainly be incorrect to \xy to find 

 mainly in these the cause of those varieties; in the same region different 

 forms sometimes occur, whereas specimens from different islands, on the 

 contrary, sometimes differ very litde or not at all. 



The under-side of this butterfly, in so far as it is not covered while in 



