43 



of diffusion of fhe black pigment has advanced more or less. In specimens 

 where the black is still on the increase this spot is most pronounced during 

 the dry season when in general the development has less advanced than in 

 individuals living in the rainy season, hence the form Ismexe was believed to 

 be a dry season type. It is, however, invariably of small size ; such large 

 yellow spots as figured by Moore for many of his alleged species from 

 British India and which also occur in races of Cyllo in the west of the 

 Malay Archipelago, are not met with in Java; only in some $ from E. J. 

 (PI. XV, fig. 305?) the orange shade is likewise fairly diffused. These are, 

 however, very useful for understanding the existence and history of this spots 

 in Cyllo Leda L., by means of comparison with them, as has been done in 

 the introduction. We have here, evidently, to do with what in the introduction 

 to mv monograph of the Java Pieridae I have termed obstinate spots, in which 

 the original colour — whether red or, at a more advanced stage, orange or 

 yellow — is retained for a long period before being covered by the black 

 pigment. The intense black b)' its side must, as has been explained in the 

 introduction with reference to the true ocelli, apparently be looked upon as an 

 accretion of this black pigment at the place where the said obstinate spot caused 

 an obstruction to its even diffusion in the manner this has taken place in the 

 remainder of the wing surface. The clear white dots occurring in the spot 

 referred to must have originated in the same way as has been indicated 

 in the introduction in the case of the true ocelU. At times similar white 

 dots occur elsewhere on the upper side and it may happen that these are 

 not clear white but yellow, in which case the scales are still filled with some 

 faded and, therefore, yellow pigment. To utilize such white dots as specific 

 characters simply signalizes a complete want of grasp of the process of colour 

 evolution. 



The course of this process on the under side is much more intricate. Here 

 also the original red is covered by the black pigment and the latter has subse- 

 quently decreased step by step, but in so uneven a measure that it occurs 

 in all manners of blends with the remnants of the original colour, in which the 

 latter — although sometimes already faded to yellow — is still distincdy 

 discernable. Two vertical, parallel, curved stripes on the under side ot the 

 tore-wings are first of all to be regarded as vestiges of the former general 

 darkening process, the inner one being continued on the hind-wings, while both 

 occur in various stages of fading and diminution, being wider at one time 

 (PI. XV, fig. 30//, w) and narrower at another (PI. XV, fig. 30 X-, /, ;/) ; some- 

 times they are very dark (PI. XV, fig. 30 //, ;//) but not unfrequently the 

 original red is distincdy recognizable, more so than is shown in the illus- 



