- Antennæ clavo elongato, compresso, obtuso terminatæ. Palpi exserti, recti, approximantes, squamis obtecti, imberbes, articulo ultimo nudo, gracili, acuto. Oculi semicirculares. Alæ anticæ trigonæ; posticæ dentatæ, caudatæ, lobo ad angulum analem obtuso, concavo, quem sedentes vibrant, instructæ. Thorax validus. Abdomen gracile.
Typus Genericus Papilio Betulæ, &c. Lin.
- Antennæ ending in a lengthened, compressed, and obtuse club. Palpi exserted, approximating, covered with scales, but without hairs, the last joint naked, slender, acute. Eyes semi-circular. Anterior wings trigonal, the hinder dentated, generally tailed, with an obtuse concave lobe at their anal angle, which is generally in motion when the insect is at rest. Thorax strong; body slender.
Generic Type Papilio Betulæ, &c. Lin.
- T. alis fuscis, colore violaceo nitidis, posticis caudatis, margine rubro, subtus maculo nigro lunulâque rubrâ ornatis; lobo anali suprà ærato, subtus nigro.
- Wings brown, glossed with violet; posterior tailed, with a red margin, beneath with a black spot and red lunule, anal lobe above bronzed, beneath black.
The beautiful little Butterflies included by Fabricius in this genus, are scattered over all parts of the world, but are most numerous within the tropics, and particularly in South America, for in Brazil alone I collected near 120 species. They are an obvious and very natural family, though the species are as yet but little understood, and not one half of them described. I have observed a singular peculiarity in a great many of these insects, which is, that when they are at rest in the sun, the lower wings are constantly in a quick vibrating motion up and down, as if the insect was rubbing them together, more particularly where the two lobes (or obtuse tails) of the under wings meet, though what purpose this is intended to accomplish remains unknown.
The upper surface of the wings in the greatest number of the Hair streaks (as they are aptly called by English collectors) are of various shades of vivid blue, so that the species can only be ascertained from the under markings, which are usually very striking and delicate: they are all of a small size.
This is an African species, and both sexes are in the cabinet of my friend Mr. Haworth.