Such a remarkable discrepancy exists in the appearance of the sexes, that they were always regarded as separate species till lately, when their proper relationship to each other happened to be ascertained. The anterior wings of the male are deep velvety black, with two broad longitudinal stripes of rich silky green, curved, and narrowing at both extremities; between these stripes there is a large brownish spot disposed longitudinally. The hinder wings are silky green, with the posterior margin, and a series of four pretty large circular spots, velvet-black; between the black spots and posterior border are two orange spots, and another of larger size towards the base of the wing. On the under side, the anterior wings have a macular band of gilded green, formed of contiguous wedge-shaped spots, an irregular patch towards the centre, and two streaks near the apex. The under side of the hinder wings corresponds to the surface, but the green is of a more golden hue, and the circular spots larger, and seven in number. The antennæ, head, and thorax, black--the latter with a central line and two posterior spots of golden green; breast spotted with red on the sides; abdomen bright yellow. The female is considerably larger, frequently measuring nearly eight inches between the tips of the wings. The prevailing colour is dark brown, deepening towards the extremities of the wings; the upper pair traversed by a macular band of impure white, the spots unequal and generally interrupted or notched; the hinder pair having a curved row of six large wedge-shaped spots behind, of a whitish colour powdered with black, the base tinged with yellow, and each with an orbicular black spot in the centre. Head and thorax entirely black, the abdomen whitish yellow above and deep yellow beneath. Varieties of both sexes have occurred, for there seems little reason to doubt that the insect figured by Guerin (_Voyage de la Coquille, Ins._, pl. 13, fig. 1 and 2) under the name of _P. urvillianus_, is a variety of the male, while a female variety is described by Boisduval[28]. In the former, the green of the superior wings is replaced by violet-blue of a very brilliant tint, and in the hinder part that colour runs in a broad stripe along the nervures, dilating considerably towards the posterior margin. This example was found at Offack. The Priam butterfly is found in the islands of Amboina, Rawack, and Ceram. It has been observed to hover about the _Mangifera Indica_ in preference to other trees, and it has hence been conjectured that it deposits its eggs on the leaves, and that they constitute the food of the caterpillar. It never occurs in large numbers, and is hence somewhat rare in collections. Specimens of both sexes are preserved in the valuable collection of insects belonging to the Edinburgh University Museum. ORNITHOPTERA REMUS. PLATE 1. Fig. 2.