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Show 290 MR. A. G. BUTLER ON A NEW FOSSIL MOTH. [May 21 , Lithopsyche than Calospila leucomela still exists, it is probably to be found in one of the islands between Java and Australia. I have already stated m y belief that the Nymphalidae, and in fact most Lepidoptera, were originally black and brown, but the Pierinae and, I might add, probably the Geometrites were white, or white with black bodies. It is perhaps worth while to show some reason for this belief beyond those already given. Assuming that the Nymphalidae were for the most part originally black, or black and brown forms, there should be a far greater proportion of violet, blue, crimson, and reddish orange in this family than in a group such as the Pierinae, presumably developed from forms which were originally either wholly or for the greater part white : the aberrant types also would, I think, be more likely to revert to melanism in the Nymphalidae and other dark groups, and albinism in the Pieridae -*-. In the Euploeinae, one of the larger subfamilies of the Nymphalidae, a considerable proportion of the species are black or dark brown, many of them suffused with violet or blue, and in the more highly coloured forms with patches of blue in the centre of the wings. O n the other hand, there are not a few genera in which white, pale yellow, or green are the predominant colours, and these may have been modified from forms originally either white or black, most of these genera showing extreme types of colouring in some of their species. In the Pierinae there are hardly any genera in which white species do not still exist and forms with white females are abundant; it is also a significant fact that Ganoris rapee (probably introduced into the United States about 1856-7) suddenly developed the yellow form G. novangliee. Indeed the change from white to yellow seems so easy that one can almost be certain that the latter has been derived from the former and is the result of a more vigorous constitution 2. In the Geometrites also it is not unusual to find white and bright yellow species in one genus, and occasionally individuals of the same species differ in a similar way-Syllexis lucida from Chili is either shining lemon-yellow or silvery white. I^ow I think, if it be admitted that the earliest types of Geometrites were black with white markings or vice versa and that the white was gradually modified into yellow and the black into blue, one can conclude that Milionia, the most highly ornate genus of the Geometrites, was one of the last developed, or at any rate has passed through more stages of development than any of its allies. Assuming that it has been produced from such a form as Lithopsyche, the white bands have first become clear yellow as in Bociraza, then saffron as in Bordeta quadriplagiata, orange as in Milionia zonea, partly crimson as in M. snelieni, or wholly crimson as in M.guentheri; We obtained a singular albino of Hebomoia glaucippe from Dr. Lidderdale's Darjiling series ; in this specimen all the black markings are replaced by white. 2 Some years since I found a wild white primrose, which I planted in my garden and hoped to multiply, but it yielded no seed and division of the root destroyed it entirely. |