52 FOSSIL BUTTERFLIES. 



scarcely reaches the middle of the costal border; the discoidal cell is but little 

 more than half the length of the wing; the subcostal nervure has but two superior 

 branches, although the outer is not only itself forked, but its upper fork is 

 branched at the extreme tip of the wing; the first superior nervule is emitted at 

 some distance previous to the tip of the cell, or opposite the base of the first 

 median nervure; it terminates in the middle of the outer half of the costal 

 margin, and the forked branch of the outer superior nervule supports the extreme 

 apex of the wing; the inferior subcostal nervule arises midway between the bases 

 of the two superior nervules, and terminates about one-third way down the outer 

 border; the vein closing the cell strikes it near the base and has an inward con- 

 vexity, meeting the upper median nervule farther from its origin; the first median 

 nervule originates at some distance beyond the middle of the cell. 



In the form of the wing and its neuration this fossil group is more nearly 

 allied to Delias (PL II, fig. 4) than to any other genus I have been able to ex- 

 amine. It is plain at first glance that it must be placed in the vicinity of 

 Delias, Thyca, Prioneris and similar East Indian Pugacia, in which there are but 

 two superior subcostal nervules, and in which the outer of these is forked; but I 

 have met with no instance among these in which one of these forks is itself 

 branched; and this insect differs notably from them all in the elongate form of 

 the wing, the remarkably straight costa 1 and the shorter discoidal cell; and from 

 all Pierids in the shortness of its costal nervure and the basal extension of the first 

 superior subcostal nervule; this latter nervure always originates, in every living 

 type I have examined, at or beyond a point opposite the middle of the space 

 between the bases of the first and second median nervules. 



COLIATES PROSERPINA SCUDDKR. 

 Plate II, fig. 5. 



The fossil to which I have given this name is exceedingly obscure, having no 

 color whatever distinct from the stone in which it is imbedded ; this is of a chalky 

 gray color. I have seen both impression and reverse, the latter a little in relief. 



1 See, however, the American genus Leortonta. 



