four to six inches, the female considerably larger than the male.
The caterpillar, which is well figured by Abbot and Smith (vol. ii. pl. 55), varies very much in colour, being sometimes, as these authors express it, tawny like a negro, at other times orange and tawny, and occasionally green. It has two short rugose horns on each of the second and third segments, and some minute sharp points on the others, from which pretty dense tufts of long rigid hairs arise. There is a small yellow spot, surrounded with a black ring, on the side of all the segments, except the three immediately behind the head. It feeds on the plane-tree (Platanus occidentalis, Linn.), likewise on the oak, liquid-amber, and pine. The species breeds twice a-year, in June and September. "The caterpillar," says Abbot, "went into the ground September 16, and came out July 4th. The caterpillars are not common, and are the most difficult of all to bring to perfection in confinement, as they will not eat in that situation; and even if they change into a chrysalis, they die afterwards."
