We are indebted to Madam Merian for a representation of the caterpillar, the peculiar appendages of which have been already mentioned. The colour of its body is a delicate green, with longitudinal rays alternately blue and yellow; the pectoral legs black; the head dull yellow. It feeds on the _Jasminum Indicum_. The chrysalis is of a yellow colour. The insect inhabits various parts of South America, in some places rather plentifully. MARIUS THETIS. PLATE XIX. Fig. 1[34]. Pap. Thetis, _Fabr._--Nymph. Thetis, _Godart_.--Pap. Petreus, _Cramer_, Pl. 87, fig. D, E; _Stoll’s Supp._ Pl. 2, fig. 2, A, (caterpillar), fig. 2, B, (chrysalis); _Swainson’s Zool. Illus._ Pls. 59 and 110. This singular looking insect is distinguished generically by the peculiar shape of the wings, and the equally remarkable appearance of the caterpillar. Of the former the posterior edge of the primary pair is concave, and the apex is distinctly truncated; the same edge of the secondary wings has two long linear tails, the anal one shorter and curved outwards, the external long, obtuse at the extremity, and turned somewhat obliquely outwards. The caterpillar is naked, with four long fleshy filaments on the back, and two others projecting from the hinder part of the head; the chrysalis likewise with several projecting filaments. The Marius butterfly is a native of Guiana and Brazil. The colour of the upper side is tawny, varying somewhat in the shade according to the sex, the surface traversed by three black narrow lines, running obliquely from the anterior to the abdominal margin: near the base, and between the second and third lines are the rudiments of two others, and the costa is likewise black, as well as the posterior margin behind the middle: the under wings are black along the hinder edge, and likewise the tails, and on the anal angle are a few whitish crescents placed over two black points surrounded by a white circle. The colour of the under side is rusty-brown, glossed with violet and pale green, and across the middle of both wings there is a dark oblique line, having a series of black ocellated spots behind it. [Illustration: PLATE 19. _1. Marius Thetis._ _2. Fabius Hippona._ Guiana. _Lizars sc._]