This insect affords an example of a pretty extensive and beautiful group which is strikingly characterised by the prevalence of a peculiar colour and uniformity of design in the markings. The ground colour is a rich chestnut-brown, varying considerably in the intensity of the shade, the wings widely margined on the outside with black, more or less interrupted with white spots; the black colour sometimes running along the nervures in a broad stripe. They are common both to the old and new world, and many of them are very abundant. _E. Plexippe_ occurs in the East Indies and China, also in the islands of Java, Ceylon, &c. and often appears in great plenty The colour is light chestnut-brown, approaching to fulvous, the whole external border of the wings with a broad black band, dilated at the apex of the superior pair so as to occupy the whole angle; this band bears two rows of small unequal white spots, and the black space at the summit of the upper wings has a broad oblique band of pure white, angular on the edges, and formed by the confluence of five spots; between this and the middle of the costa is a small group of white spots: all the nervures black and dilated. The under side differs in having the space between the white patch at the apex of the upper wings and the external margin ashy-brown; in having the ground colour of the inferior-wings pale fulvous, and the nervures of the same wings narrowly edged with white. The abdomen is nearly of the same colour as the wings; the thorax, breast, and head black, punctured with white; antennæ black, the extremity of the club rust-red. GENUS IDEA. The above genus is of very limited extent, comprehending only four species. They are, however, somewhat remarkable insects, both on account of their size, and the manner in which their colours are distributed. The wings are slightly transparent and of a greyish white, with black stripes running along all the nervures, and occasionally forming blotches on the surface. The nearest approach to this mode of colouring among other tribes is presented by certain species of Euplœa, and particularly by _Pap. dissimilis_, which on this account, has been termed the Idea-likeness butterfly. The most conspicuous of its generic characters are the slenderness of the antennæ, which are so slightly thickened towards the apex as to appear nearly filiform, and the elongated oval form of the wings: in other respects Idea nearly conforms to the genera with which it is associated. The palpi have the terminal joint minute and conical, the second long and thickest in the middle, the radical one net half its length. The tarsal division of the anterior legs is dilated, and furnished with two or three unequal spines. [Illustration: PLATE 10. _1. Idea Agelia._ _2. Idea Daos._ Java. Borneo _Lizars sc._] IDEA AGELIA. PLATE X. Fig. 1. Pap. Idea, _Linn. Fabr. Cramer_, Pl. 193, fig. 1, A, B, and pl. 362, fig. D.--_Donovan’s Insects of India._