The neuration of the same wing ([Pl. II], fig. 7) is very similar to that of Mylothris.[V] The costal nervure terminates at about five-sevenths the distance from the base of the costal margin to its tip; the subcostal nervure emits two branches before the cell, the second probably close to the apex of the cell, the limits of which are not given in the drawing prepared for me, but which could probably be made out by a sufficiently careful examination of the original; a third superior nervule is emitted from the subcostal nervure at less than half the distance from the origin of the second to the outer border, and the emission of the inferior nervule, if it could be traced, would mark the termination of the cell; the median nervure is of course three-branched and scarcely curves upward at all to meet the subcostal.
The design of the upper surface of the fore wing ([Pl. II], fig. 17) is simple, consisting only of a broad marginal pale band on a dark ground, enclosing small dark spots in the middle of the interspaces.
This fossil was placed by Heer among the Nymphales, and referred, like the preceding, to Vanessa. Heer lays stress on the non-closure of the cell, but it appears questionable whether this is not simply the result of the defective preservation of the fossil. Edwards has since referred it to Argynnis, on account of the general aspect of its markings, and Butler, on the same ground, to Junonia. But the new drawing of the fossil obtained for me through the kindness of my friend Herr Brunner von Wattenwyl, and by him carefully compared with the original, leave little doubt that it is a Pierid, and belongs in the neighborhood of such genera as Mylothris and Hebomoia. The latter genus it closely resembles in the form of the wings. Further comparisons are presented under the species.
MYLOTHRITES PLUTO (Heer) Scudder.
[Plate II], figs. 2, 7, 17 (15?).
Vanessa Pluto Heer, Insekt. Tert. Œning., ii, 179-82, Taf. 14, fig. 4, 5 (?) (1849); Ib., Nouv. Mem. Soc. Helv., xi, 179-82, Tab. 14, figs. 4, 5 (?) (1850); Gieb., Deutschl. Petref. 644 (1852); Ib., Faun. der Vorw., 186-7 (1856); Pict., Traite de Palæont., ii, 393, pl. 40, fig. 21 (1854); Lyell, Elem. Geol., 6th Ed., 243, fig. 179 (1865).
Argynnis Pluto Edw., Butt. N. Amer., I, Argynnis I, fig. (1868); Kirb., Syn. Cat. Diurn. Lep., 155 (1871).
Junonia? Pluto Butl., Lep. Exot., 127-28, pl. 48, fig. 7 (1873); Ib., Geol. Mag., x, 3-4, pl. 1, fig. 7 (1873).
Heer’s description of this insect is as follows:[W]—