The caterpillar, which feeds on the different kinds of _Citrus_, is described by Dr. Horsfield as of a green colour, with an ocelliform lateral mark on the third segment, and a transverse white band; a band of pale green between the fourth and fifth segments, and an oblique white stripe on the eighth and ninth; the anal segment likewise of that colour. The anterior part of the body is considerably attenuated, similar to what is observed in the caterpillars of many of the Hawkmoths. Chrysalis green, reddish-yellow on the back. This insect is found in China, and the islands of the Indian Ocean, and is rather a common species. PAPILIO ÆNEAS. PLATE II. Fig. 2. _Linn., Fabr., Cramer_, Pl. 279, Figs. A, B, C, D.--_Rösel Insect._ vol. iv. Pl. 2, Fig. 2.--_Godart, Encyclop._ No. 24.--_Boisduval, Spec. gener._ 286, No. 112. We have figured this insect as characteristic of a pretty extensive group of butterflies inhabiting South America, distinguished by a peculiar outline, and a certain similarity of design in the markings. The space between the tips of the anterior wings always exceeds by more than one half the space between the anterior edge of these wings and the hinder margin of the posterior pair; that is to say, the width of the insect, with its wings expanded, is more than double its length. The ground colour of the wings is generally deep black, with one or two insulated patches of some light colour on the disk of the anterior pair, and a large blood-red patch in the middle of the hinder wings; the latter deeply dentated on the margin, but without a tail. In _P. Æneas_ the upper wings expand about three inches and a quarter: they are velvet-black, becoming lighter towards the apex, with a pretty large green spot, of a somewhat quadrangular shape, towards the interior border, surmounted by three smaller ones of an obscure white. Inferior wings likewise velvet-black, with a large discoidal patch, deep red anteriorly and carmine behind intersected by dark nervures; posterior margin with obtuse unequal dentations, the notches margined with red. Under side of the inferior wings with five oval, rose-coloured spots, placed in an irregular transverse line. Body black, the sides of the breast spotted with red. The insect regarded as the female of this species differs greatly from the above: the wings are more rounded at the apex, and there is only a single spot, of shining green, on the upper pair: the notches of the hinder wings bordered with white. This butterfly is found in greatest plenty in Surinam, but it likewise occurs in other quarters of South America. The other species belonging to this group, easily recognised by their peculiar _facies_, are, _P. Opleus_, _Hippason_, _Euristeus_, _Polymetus_, _Jacinthus_, _Eurymas_, _Eurymedes_, _Echelus_, _Ariarathes_, _Marcius_, _Numa_ (Boisd.), _Cœlus_ (Lacordair), _Arbates_, _Anchises_, _Dimas_, _Iphidamas_, _Arcas_, and a few others. [Illustration: PLATE 3.