This magnificent species is usually about the size of _Papilio Machaon_, but sometimes it is a good deal larger. The surface is a deep, velvet-black; the upper wings with numerous transverse lines and stripes of beautiful golden-green, and a broad band of the same colour near the middle deeply cleft anteriorly: this band is likewise continued across the under wings in the direction of the anal angle, but a large space on the latter is brilliant coppery-red with a violet reflection, and marked with four or five black spots; besides this there is another green band near the external margin, the outer edge as well as the tails fringed with hairs: the tails are three in number, that most remote from the anal angle longer than the others. On the under side of the superior wings the green bands are dilated so as to occupy greater part of the surface; the same side of the inferior pair is gilded green at the base and extremity; the whole anal region bright flame colour inclining to purple, with a changeable lustre, prolonged to the anterior margin and forming a central band, the whole surface marked with orbicular black spots, which become larger posteriorly. Body black, fulvous beneath: antennæ wholly black. The female is about one-third larger than the male, the anal mark larger and of a golden colour with little mixture of purple. “This species,” says M. Boisduval, who first completed the natural history of this insect by describing its various states and metamorphoses, “which may be considered as the most beautiful lepidopteron known, inhabits Madagascar. It has been once taken in Bourbon, whither the caterpillar had probably been transported accidentally. According to Cramer it is likewise found on the coast of Coromandel. “The caterpillar lives on the _Mangifera Indica_. On first issuing from the egg, it is nearly smooth and of a greenish tint; after the first moult it assumes a black colour, becomes covered with spines, and protrudes at pleasure two rose-coloured retractile horns, placed on the first segment. Having attained its full size it is rather slender, dilated laterally towards the middle, and is about two or three inches long. On each side there is a festoon composed of many irregular bands of white, green, and yellow points: the horns, which were of a delicate rose-colour, become carmine-red; the first pair of membraneous legs becomes very short, almost rudimentary, and are of no use in walking; when in motion, therefore, it curves the centre of its body upwards into a loop like the caterpillars of _Geometra_ and _Catocala_. Before undergoing its metamorphoses, it attaches itself by the tail and a band round the middle, like the caterpillars of _Papilio_, _Colias_, _Pieris_, &c., or rather like those of _Geometra pendularia_ and _Gyraria_.