According to the above definition, the genus comprehends rather upwards of 220 species. They are distributed over almost every quarter of the globe, but are by far most abundant in intertropical countries. They are more numerous in the new continent than the old, but the difference is by no means considerable. In the former, Brazil alone produces between forty and fifty species; in the latter, the greatest number occur in the islands of the Indian Archipelago, already referred to as the native country of the magnificent Ornithoptera. The continental parts of India, China, Java, &c. likewise possess many fine species, and a few are found in New Holland. Europe is exceedingly poor in insects belonging to this group, there being only four indigenous kinds. These are _P. Xuthus_, _P. Alexanor_, _P. Machaon_, and _P. Podalirius_; the two latter, which are the most common, are well known to extend to Britain. The first species selected to exemplify one of the prevailing forms of this important genus, is [Illustration: PLATE 2. _1. Papilio Memnon._ _2. Pap. Æneas._ _Lizars sc._ China. Surinam.] PAPILIO MEMNON. PLATE II. Fig. 1. _Linn. Fabr. Cramer_, 91, C.--Papilio Agenor, _Linn. Fabr. Cramer_, 32, A, B. The upper wings in this species expand about five inches; they are blackish and marked with numerous longitudinal rays of a greyish-ash colour, each of them having a large blood-red or ochrey-yellow triangular patch at the base. The inferior wings are waved on the hinder margin, and narrowly edged with white in the emarginations, the disk almost entirely occupied by a broad white band divided by the dark nervures, the hinder portion dusky with a series of deep-black spots of an ovate or rounded form, that placed on the anal angle smaller than the rest and encircled with fulvous, which colour extends to the extremity of the internal border; on the under side they are spotted with red or ochre-yellow at the base: body black, the prothorax marked with several white points. The above description applies to one of the female varieties of _P. Memnon_, which was usually regarded as a distinct species and known by the name of _Agenor_. Indeed it is so unlike the male, that authors would probably never have thought of associating them, had they not been reared from the same description of caterpillar. The male is entirely without the basal red spot, and the dark ground colour has a greenish reflection; the upper wings have a red or ochreous spot at the base on the under side, and there are likewise four small red marks on the same part of the inferior wings: the latter are deep black anteriorly and cinereous behind; the cinereous portions containing two rows of deep black rounded spots, that next the anal angle encircled with yellow. _P. Androgeos_ of Cramer (pl. 91, A. B.) is a variety of this sex, while the _P. Anceus_, and _P. Laomedon_, of the same iconographist are varieties of the female.