The female lays her eggs singly. They are laid at the tip of the host plant leaf (the host plant is the plant that the caterpillar feeds on). The egg is pale green or pale yellow. It turns gray later. The caterpillar feeds at night. It mimics a bird dropping. It is white, brown, black, and olive green. There are two greenish bumps on the thorax. There are also two spines near the head. The chrysalis also mimics a bird dropping. It is white, brown, and black. There is a large brownish bump on the abdomen. The caterpillar hibernates in a leaf shelter. It lays one set of eggs in northern Canada, and 2-3 more groups in southern Canada and the United States.