As a specimen of that division of Morpho which has the upper wings scarcely or not at all concave on their outer edge, and the anal angle of the under pair prolonged into an obtuse rudimentary tail, we have represented a species of great beauty although inferior in size to many of its congeners, the expansion of the wings seldom exceeding three inches and a half. The surface of the male, when seen in certain directions, is of the most brilliant azure-blue, the whole of the exterior margin of the primary wings surrounded with black, and near the apex are two small white spots, the anterior one longitudinal, the other orbicular. In the female the blue colour has not such a high degree of lustre; the posterior margin is widely black, and bears two rows of white spots in the upper wings and one row in the under. On the under side the colour is greyish-brown, with several common oblique bands of a paler hue, and three or four oblong ocelli with a white pupil and a black iris surrounded by a yellow ring; the anal angle marked with short undulating black lines. Body brownish-black above, concolorous with the same face of the wings beneath. [Illustration: PLATE 22. _1. Morpha Adonis. 2. Pavonia Teucer_ Brazil.] Found in various parts of South America, but apparently most plentiful in Brazil and Guiana. GENUS PAVONIA. The group composing this genus was separated from the preceding by Godart, chiefly on account of the discoidal cell in the secondary wings being closed. Besides this character the palpi are not so densely clothed with scales, and the inferior nervure of the upper wings is curved near its origin in the form of the letter S. The species very closely resemble the _Morphos_ in most other respects, but their colours are generally less brilliant. They are all from South America, and in that country they are far most abundant in Brazil. The caterpillars of several different kinds have been represented by Madam Merian, and, like those of _Morpho_, they differ from each other in their appearance and properties. PAVONIA TEUCER. PLATE XXII. Fig. 2. Pap. Teucer, _Linn._--_Merian, Surinam Ins._ Pl. 23; _Cramer_, Pl. 51, fig. A, B.