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Genus IDEA.
The above genus is of very limited extent, comprehending only four species. They are, however, somewhat remarkable insects, both on account of their size, and the manner in which their colours are distributed. The wings are slightly transparent and of a greyish white, with black stripes running along all the nervures, and occasionally forming blotches on the surface. The nearest approach to this mode of colouring among other tribes is presented by certain species of Euplœa, and particularly by Pap. dissimilis, which on this account has been termed the Idea-likeness butterfly. The most conspicuous of its generic characters are the slenderness of the antennæ, which are so slightly thickened towards the apex as to appear nearly filiform, and the elongated oval form of the wings: in other respects Idea nearly conforms to the genera with which it is associated. The palpi have the terminal joint minute and conical, the second long and thickest in the middle, the radical one not half its length. The tarsal division of the anterior legs is dilated, and furnished with two or three unequal spines.
