The caterpillar (Pl. VIII. fig. 2) is green, covered with small black granules, and having a yellow line along each side, surmounted by another of a blue colour. It feeds on the different kinds of _Cassia_. The chrysalis (Pl. VIII. fig. 3) is likewise green, changing ultimately to brown. The butterfly is very common in Guiana, Brazil, and many other parts of America. GENUS TERIAS. We owe the establishment of this genus to Mr. Swainson. It includes a considerable number of species, the greater proportion of which have been but lately discovered. They are small insects, of delicate structure, and usually of a light yellow colour, with the apex of the upper wings deep black. The caterpillars, as far as we are acquainted with them, are attached to leguminous plants, and live between the tropics both of the old and new world. The most important generic characters are the following: antennæ of moderate length, the articulations pretty distinct, terminating in an ovoid or conical club, which is slightly curved downwards, and compressed laterally: palpi very short, the terminal joint half the length of the preceding one, naked, and a little salient; abdomen slender and compressed, nearly as long as the inferior wings; wings of delicate texture, the costal line a good deal arched towards the base. Caterpillars slender, linear, and pubescent; chrysalis a little arched, and somewhat compressed, terminating in a point anteriorly. TERIAS MEXICANA. PLATE VIII. Fig. 4. _Boisd. Spec. gen._ p. 655. Pl. iii. C, fig. 1. This insect was discovered not long since in Mexico, and is considered rare. The colour of the surface is very bright citron-yellow, the upper wings with a broad black border externally, which ends in a quadrangular expansion a little before the middle of the internal margin. The under wings have the outer border prolonged into an acute angle, forming a kind of rudimentary tail, and the anterior half is widely bordered with black. The primary wings are pale citron-yellow on the under side, with a central black point, and have the outer border near the fringe tinged with red; the secondary pair yellow, speckled with ferruginous particles, and having a black point in the centre, the extreme angle marked with a ferruginous spot, and the posterior half with four or five other spots of the same colour, having sometimes a tendency to form an irregular transverse band. The above description applies to the male; the female has the surface of the wings whitish-yellow, with the black border broader, and the anterior margin of the secondary wings widely orange-yellow. The expansion varies from twenty to twenty three lines. GENUS EUPLŒA.