We have received more than usual pleasure at seeing our name affixed to this charming bird, and in clearing up its history. (_Ill. of Orn. vol. 3. p. iii._) As a child we well remember our unwearied delight at seeing its figure in _White's Voyage_. As a collector we have preserved a series of nearly twenty specimens, and as a naturalist our name is no longer excluded from the Ornithological Nomenclature of New Holland. It is indeed somewhat curious, that while we were giving information to one of the writers in the _Lin. Trans_. upon the subjects of his paper, he should have studiously witheld from us the only public acknowledgement, for such assistance, it was in his power to make. * * * * * * [Illustration: PROTESILAUS _Leilus_.] PROTESILAUS Leilus, _Protesilaus Butterfly_. ---- Genus Amphrisius, _Sw._ Sub-genus Protesilaus, _Sw._ SUB-GENERIC CHARACTERS. Wings trigonal, acute, yellow with black transverse bands; the inferior lengthened, narrowed, with two long acute tails; antennæ short, the club thick, slightly compressed, but solid, and convex all round; front very hairy; _Larva_ covered with sharp spines. _Pupa_ braced, but suspended downwards. Type, Pap. Protesilaus. AUCT. ---- SPECIFIC CHARACTER. _Wings straw-colour; the superior with four, short, black, costal bands towards the base, and two towards the exterior margin; the latter uniting at the posterior angle._ Pap. Protesilaus. _Lin. Fab. Ent. Sys. 3. pl. p. 23. Ency. Meth. p. 50. Merian Sur. pl. 43. Cramer, pl. 202. f. a. b._ ---- From the resemblance which this insect bears to the rare British species, named by collectors the scarce Swallow-tail, (_Papilio Podalirius_,) it is generally called the Brazilian Swallow-tail. We advert to this circumstance, trivial as it may sound to scientific ears, first because it is one of the many proofs in which the nomenclature of the vulgar conveys greater information than that of the professor: and secondly, because these very names, in numberless instances, imply a perception of natural analogies, which, without the labour of philosophic research, suggest themselves to unscientific observers. In the present instance, these facts may be verified in the most unquestionable manner. According to our views, _Protesilaus_ not only represents one of the primary groups of the Lepidoptera, but also typifies the Fissirostral birds, of which the swallows are the most pre-eminent. Madam Merian's valuable work on the Insects of Surinam, has furnished us with a figure of the larva; which, unlike that of the European Swallow-tails, is covered with spines: the chrysalis also departs from the usual type of the family, in having the head directed downwards. These facts we have verified by an inspection of the original drawings, of M. Merian, now deposited in the British Museum. These are all important variations in structure, which can only be explained by the natural system.