The genus to which we have assigned the above name has been hitherto blended with the UraniÆ. It is doubtless very closely connected with these insects; but the differences both in the appearance of the perfect insects and the respective caterpillars, render it expedient that they should be separated. The character by which it and Urania are widely separated from all others, is the form of the antennÆ, which are filiform nearly to the middle, where they thicken a little, and from that gradually narrow to a point. The palpi are lengthened and slender, having the second joint greatly compressed, the terminal one more slender, nearly cylindrical, and naked. There is no closed discoidal cell in any of the wings, and almost all the nervures diverge from the base. Not many different kinds are known, and, with one exception, they are natives of America and the West Indian Islands. Their splendid tints of golden green arranged in transverse bars, render them perhaps the most chastely beautiful insects that exist, and has caused them to be named Emerald Butterflies in this country. Sometimes also they are called Pages. They fly so high in the air and with so much velocity, that it is nearly impossible, Madam Merian informs us, to catch them, and the only way therefore to obtain good specimens, is to feed the caterpillar. “Great numbers of this insect,” says Mr. Swainson, speaking of a species almost the exact counterpart of U. Leilus, “were flying during the whole of the morning, past Aqua Fria (Pernambuco) in a direction from north to south: not one deviated from this course, notwithstanding the flowers which were growing around: they flew against the wind, which blew rather strong, and near the ground, but mounted over every tree or other high object which lay in their course; yet their flight was so rapid, that I could not capture a single specimen. They went singly, and near fifty or sixty must have passed the spot opposite the window before mid-day: they continued to pass for three or four days in this manner. 12th June 181737.”

The present genus differs from Urania in the perfect insect having three distinct tails at the hinder extremity of the posterior wings; neither are these wings so much elongated as in the group just named. The differences between them in their early states will be seen by comparing the following descriptions.

THALIURA RHIPHEUS.
PLATE XXVIII.

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.

“The chrysalis is elongated and pointed, scarcely angular, of a green colour with a transverse gilded band; the extremity, which is of a deeper green, is sprinkled with a great number of golden points.

“The perfect insect comes out in about three weeks. Exposed to the sun, it developes itself completely in two or three hours, while individuals born in the shade take nearly a day to develope themselves, and are usually less brilliant.”