We have searched in vain for some account of this very distinct and handsome species, collected by our venerable and enthusiastic friend Dr Langsdorff, in the interior of Brazil; and transmitted to us some years ago, in remembrance of the many happy days we passed together in the enchanting scenery of that delightful region. We have not seen the species in any of the London collections, and we believe it altogether undescribed. The Larva and pupa are of course unknown to us, but the whole structure of the perfect insect agrees so truly with that of _Protesilaus Lelius_, that we have no doubt whatever of its belonging to the same sub-genus, and thus becoming an interesting addition to a group, capable of the most complete and diversified demonstration. * * * * * * [Illustration: PODALIRIUS _Pompilius_.] PODALIRIUS Pompilius, _Pompilius, or Javanese Swallow-tail._ ---- Sub-family Papilionæ. Genus Papilio. Sub-genus Podalirius. _Nob._ SUB-GENERIC CHARACTER. _Wings_ trigonal, acute, yellow, with black transverse bands, the inferior with two long narrow acute tails; _Antennæ_ short, the club thick and solid at the base, but greatly compressed at the tip, where it is concave beneath; _head_ small, front hairy; _Larva_ smooth; _Pupa_ braced in an erect position. _Type_ Podalirius Europæus. _Nobis._ ---- SPECIFIC CHARACTER. _Wings above pale yellow, the anterior with five short, black, stripes across the areola; and two others, much longer and broader, close to the exterior margin: posterior wings without lunulate spots._ Papilio Pompilius. _Fab. Mantissa 2. p. 8. Ent. Syst. 3. 1. p. 25. Ency. Meth. 1. p. 49. Horsf. Cat. pl. 3. fig. 5. 5. a._ (_larva and pupa._) ---- We may term this the Javanese Swallow-tail, for in that and the other Indian islands it appears to be not uncommon. We are indebted to the elegant _Catalogue_ above quoted, for our figures of the _larva_ and _pupa_; and to the rich collection of Mrs. Children for the examination of the perfect insect. Entomologists will doubtless feel surprize that this and the _Protesilaus_ on our last plate, should be placed as distinct types in two different genera. We have not done this without long deliberation; but we cannot, in a work of this nature, enter into those details which would demonstrate these divisions to be truly natural, in the most rigid acceptation of the word. We desire not, however, that Entomologists should adapt our views,--at least for the present. We hope, indeed, that they will not, because experience has shewn, that until a theory has been fully explained, more injury than good results to science, from injudiciously adopting, and hastily applying, a system not understood. We only desire, in short, to record our views, that they may be comprehended hereafter. We consider this as the Thrysanuriform type of the sub-genus, and our English _Papilio Machaon_ of authors, as the Heliconian.--_Tempus ducamus._