Zoological Illustrations Series II/Plate 88
ARCAS Imperialis.
ARCAS imperialis.
Emerald Hair-streak.
Tribe, Papiliones. Family, Polyommatidæ. Sub-family, Theclanæ, Nob.
Sub-Generic Character.
Palpi, in both sexes, very long, thick, porrect, twice as long as the head, curved downwards, all the joints entirely covered with close-set scales, posterior wings six-tailed.
Specific Character.
Above shining blue: beneath emerald-green, marked with minute black waved lines.
Papilio imperialis. Cramer, Pl. 75. f. E. F.
Hesperia Venus. Fab. Ent. Sys. 3. 1. 268.
It is impossible to depicture with correctness, the resplendant blue which ornaments the upper surface, or the vivid emerald green on the under wings, of this rare and splendid insect. It is possessed by few collectors; nor did we capture more than three specimens, during two years devoted to the entomology and ornithology of Brazil. The male is distinguished by a black central spot on the anterior wings. The very remarkable prolongation of the palpi, which are alike in both sexes, induces us to consider this insect as a type of form, or in other words, a sub-genus: but we are at present unprepared to state any thing satisfactory on its true affinities.
We have thought it right in this and other instances, to retain the original specific name of Cramer; and we shall do the same in all instances where it will not produce a discordant union of generic and specific names. On this head, as the principle of Linnæus, from the great number of new genera since defined, can no longer be acted upon, we think that specific appellations, derived from some character of the insect, are much better, in every respect, than attempting to render the nomenclature of the Lepidoptera a correct index to the mythology of the Ancients.