Genus. Papilio, Linn. &c. (Section Equit. Achiv.)
Papilio Nireus. Alis dentatis, nigris, fasciâ communi maculisque viridibus; posticis breviter caudatis; his subtus fasciâ subargenteâ, marginali, nervis divisâ. (Expans. Alar. unc. 4. lin. 8.)
Syn. Papilio Nireus, Linn. Syst. Nat. 2. p. 750. No. 28. Fabr. Ent. Syst. III. 1. p. 36. No. 106. God. Enc. Méth. ix. p. 48. No. 67. Cram. 187. A. B. & 378. F. G. Herbst. Pap. tab. 37. f. 1. 2. Boisduval. Hist. Nat. Lepid. 1. 224.
Habitat: Sierra Leone (Drury). Coast of Guinea, Caffraria, Madagascar (Bdv.). India (Linn. & Fabr.).
Upper Side. Head, thorax, and abdomen velvety black. Wings fine deep black; with two narrow bars of a beautiful Saxon or blueish green colour, which begin about the middle of the anterior edges of the anterior wings, and crossing both them and the posterior, meet at the abdominal edges near the abdominal corners, running parallel with the external edges. Anterior wings with two small blue spots placed on each near the tips, and another, larger, divided into three by the nerves, near the middle of the anterior edge; being placed at the top and even with the bar, but divided from it by a small separation of black. The edges of these wings are entire. Posterior wings with six blue spots on each, placed along the external edges; the four lower ones being in pairs, and another small one at the abdominal corners; margins deeply angulated.
Under Side. Breast and sides dark brown, spotted with white. Abdomen brown. Wings dark brown hair-coloured, immaculate, except the posterior ones, which have a row of eleven cream-coloured spots running along the external edges.
The female differs from the male in being somewhat larger in size, with the spots on the upper side of a brighter green colour, and with the marginal row of spots on the under side of the posterior wings of a pearly greyish hue, and with a tinge of this colour upon the disk of the wings. Cramer has figured the male as the female, and vice versa. Mr. Smeathman informed Mr. Drury that this insect feeds upon the orange and lime trees, about which the butterfly is always seen flying, considering it as remarkable that most of the insects which feed upon the orange or citron tribes, have some tinge of green upon them; in like manner the beautiful green snake, so common about Sierra Leone, is always to be found about these kind of trees. These circumstances led our author into a series of observations which, though upwards of half a century old, may still be read not only with pleasure, but with the hope of beneficial results.
"The particular qualities, dispositions, and uses of by far the greater part of insects, as well as of plants, are at present totally unknown to us, nor are the methods by which we are to acquire that knowledge at present ascertained.
"Their colours have hitherto been of no further use to us than merely to discriminate one genus or species from another; and yet it is possible that, by a combination of observations even on the colours of insects, we may form some ideas of their natures and properties.
"The observation of Mr. Smeathman, if well founded, supposing it did not lead to a discovery of the nature and properties of an insect itself, might at least indicate those of the plant on which it feeds. The various species of the Danai Candidi, among which are included the different white butterflies of Europe, feed chiefly on such plants as are reckoned not only nourishing, but salutary to the human body, such as the various species of cabbages, coleworts, turnips, &c. Every foreign country produces butterflies of that family; some of them so very like those of Europe, that it is a fair inference they feed on plants of a similar property. This is countenanced by many corroborating circumstances. The Papilio Iris, and the various Fritillary butterflies fly exceedingly swift; and it appears from Mr. Smeathman's observations, that foreign butterflies that bear a resemblance to them, also fly exceedingly swift. The green and golden Scarabei of this country are found to delight in flowers; those of the hot climates are also found on flowers; while the black, purple, and darker coloured Scarabei, are generally found frequenting the excrements of animals, and are, in every quarter of the globe, called Tumble dung-beetles, from their making balls of those substances, and rolling them to their holes. The locust tribes feed here chiefly on grasses and roots; so it appears they do in the torrid zone. Those of the torrid zone are found to be wholesome food. The inference is plain, that those of this climate, in case of necessity, or perhaps even as an article of luxury, might be found the same.