( cvi ) 



pronounced, and the iimbriae, like those of E. cleodorn, are 

 wavy. The disc in bbth these sjtecies is remarkably small, 

 contrasting strongly with that in the two preceding groups. 

 Another point of difference is that in Eronia proper the 

 scent-scales seem to be generally distributed, and not gathered 

 into definite spots. 



In Madagascar there occurs a curious form, " Ptychopteryx" 

 lucasii, the affinities of which are doubtful, though on the 

 whole it seems more nearly allied to the Eronia group than to 

 any other assemblage of Pierines. Its plume-scales, which 

 are very numerous, do not give much help towards determin- 

 ing its position, for they may be said to be unique. The 

 lamina is somewhat slug-shaped, expanding proximally. The 

 apex is blunt and the fimbriae short. The base ends in two 

 thin, sharp-pointed coinua, inclined towards one another in 

 the form of a V ; the points sometimes meet one another, 

 sometimes overlap. Between them the footstalk passes to a 

 large, clear, nearly circular disc. The scale by its general 

 outline, its blunt apex, short fimbriae and unusually large 

 disc, shows points of resemblance to that of Leuceronia 

 huquetii ; the latter, however, gives no indication of the sharp- 

 pointed, introverted basal cornua which form one of the 

 stiangest features of this remarkable structure. The ordinary 

 scales are frequently spatulate, in which respect they bear 

 some resemblance to those of the African genus Pinacopteryx, 

 but this correspondence, such as it is, is not borne out by other 

 characters of the two genera. 



We come next to Euchloe, the genus of the Palaearctic and 

 American orange-tips. In some species the plume-scales 

 appear to be entirely absent ; I have found none, for example, 

 in E. scolymus, E. sara, and E. euphenoides. In E. genutia, 

 E. piina, and E. etipheno they are scanty ; E. cardamines and 

 E. atisonia have them in fair numbers, while in E. creusa, 

 E. hellezina and E. helemia they are abundant. The scent- 

 scales of most of the species that possess them resemble each 

 other in general cbaracter. A marked feature that they have 

 in common is the small size of the accessory disc ; this is 

 especially noticeable in E. cardaminfis and E. helemia. In 

 some species the sides of the lamina are parallel or nearly so, 



