"argyrognomon" ] have in the anal area of the hindwing beneath on the black submarginal dots situated between the median branches and the submedian vein some metallic glittering scales which are usually not represented in our figures. The upperside is deep dark blue, with a broad black border, "argus" is very similar to "argyrognomon", but differs in quite a number of details, of which in the various individuals sometimes one sometimes another is more conspicuously developed. On the upperside the blue gloss is deeper, darker, duller, with a slight violet tint and not so far extended to the margm, the latter being broader and appearing blacker; the row of dark submarginal dots which occasionally appear on the hindwing above in both species, therefore stands always in the black border in argus. On the underside both sexes of "argus" have nearly always a strongly glittering blue-green dusting at the base of the wings, which is usually absent from "argyrognomon"; but we must add that also the inverse occurs, the blue basal dusting being absent from "argus" in exceptional cases and strongly marked in argyrognomon. As a rule "argus" L., moreover, is somewhat smaller than "argyrognomon", but the size varies considerably according to the altitude of the locality and the various broods.