The wingspan is about three and one-eighth to four and three-eighths inches. Although the patterns on their wings are basically the same, males are darker than females. They also show different coloration by time of year, with the second-generation males darker than those of the first generation. Males are brown. Females are yellow-brown or orange-brown. Both sets of wings have a wavy, white line about midway to the edge. An eyespot is present on each forewing. There is a T-shaped white mark on each wing. Larvae may reach two and three-fourths inches in length. They are light green with a white longitudinal stripe along the sides.
The larvae of this species feed mainly on leaves of the tulip tree (Liriodendron tulipifera) so the tulip tree silkmoth is commonly found in areas where these trees are plentiful. In Illinois, that is in the southern one-fourth of the state and along the Wabash River. This species is active at night. There are two generations per year. The pupa overwinters. The pupa is found in a cocoon of silk within a folded leaf and falls to the ground when the leaf drops.