greyish yellow, the antennæ, which are strongly pectinated in the male, ferruginous. The colour of the insect on the under side is greyish-brown, and besides the markings nearly corresponding to these of the surface, there is a dark band commencing at the anterior edges of the upper wings and continued across the disk of both in a line with the eyes, terminating at the abdominal edges just behind the body. The upper wings are strongly falcate, particularly in the male.
The eggs of this valuable species are white, round, compressed, with a depression or pit in the centre on each side; the circumference crossed with rugæ, corresponding with the rings of the enclosed animal. They hatch in from two to four weeks, according to the state of the weather.
The caterpillars acquire their full size, which is about four inches in length and three in circumference, in about six weeks; they are of a yellowish-green colour, and composed of ten segments, of which the posterior one is in some degree bifid. There is a light yellowish coloured stripe on each side, which runs from the second or third anterior segment to the incisure of the last; immediately under these stripes, the middle five, six, or seven segments are marked with an oblong gold-coloured speck. The back is also marked with a few round darker coloured spots, and a few long, coarse, distinct hairs issue from these spots, with others of a smaller size scattered over the insect. When these caterpillars approach near their full size, they are
