The leaves upon which the larvae feed may have long or short petioles. A singular account has been given of how these larvae have overcome the difficulties associated with feeding upon long-petioled leaves. There is considerable risk of falling and of the leaf breaking away when a large larva crawls out upon a slender petiole. The larva avoids these risks and yet reaches the blade of the leaf. This is accomplished as follows: The larva grasps firmly the branch with its posterior legs; reaches out a considerable distance along the petiole, and bites it through in several places. This causes the leaf to droop; the larva now reaches out, seizes the drooping leaf, and draws it within convenient reach, where it can be eaten at leisure. This is a wonderful display of instinct, yet it is not infallible, because at times the petioles are eaten too far through, and when they droop, break completely away and fall to the ground. When ready to spin its cocoon, the adult larva is about two inches long; these cocoons are very different from those of Cecropia. As a rule, they are found suspended from a branch by a silken cord, the length of which depends upon the length of the petiole of the leaf in which the cocoon was spun. Thus if the leaf has only a short petiole, this cord is also short, but if the petiole is two or three inches long, the suspensory cord is correspondingly long. The larva in constructing its cocoon, first spins a strong band around a twig, and binds the petiole of the leaf to the stem; this band extends down the petiole to the cocoon, and thus anchors it. The cocoon proper, or the part occupied by the chrysalis, is spun in a folded leaf. When this leaf dies and rots away, the cocoon hangs freely suspended by the cord, but it is very evident that the cocoon has been moulded in a leaf by the prints of the veins which remain upon it. A valve-like opening occurs in the upper end, through which the moth emerges. The wings of the chrysalis are very small as compared with those of the adult moth; are folded to the body on the under side, and covered by the pupal skin. During the winter they remain transparent since there are at this time none of the rich colors present which are later found in the moth. About ten days before the moth emerges the wings become white, a few days later definite colors begin to appear on the under side of the wings between the veins. While in the adult moths the colors in the two sexes are very distinct, at this time their wings are very similar. The wings do not long retain this similarity, but gradually become more and more unlike until maturity. Breeders of moths have often noticed that there is considerable uniformity with regard to the time of day at which certain kinds of moths emerge. For Promethea this time seems to be in the forenoon.