of the genus Pieris are white; Colias and Callidryas various shades of yellow, from the palest sulphur-yellow to deep reddish-ochre. Argynnis is almost invariably fulvous or reddish brown, variegated with numerous undulating black lines or spots; the under side more or less ornamented with silvery streaks and spots. In the species of the European genus Thais, the wings are spotted or chequered with black and red. The prevailing colour in the genus Argus is azure-blue. Danais, Idœa, and Euplœa, have this character in common, that the breast and head are always punctured with white. In Cethosia, hieroglyphical markings cover the under side of the wings in such a manner as is observable in no other genus.
Many of the caterpillars of exotic butterflies offer peculiarities in their forms and appendages, of which we find no prototype in the kinds occurring in Britain. In the place of spines, some have the body thickly covered with long fleshy prominences, of a corneous consistency at the tip, and probably serving as a means of defence. In others, spines of singular conformation and formidable size are thickly stuck over the whole surface, making it resemble a miniature forest. A few are provided with a long anal horn, resembling that which is so conspicuous in the caterpillars of the Sphinges. If Madam Merian's delineation of the larva of Urania Leilas be correct (which there is now reason to believe is the case), it bears many slender spines, as long as the whole body, and as stiff as iron wire. Another
