Northern Prairie Wildlife Research Center
Remarkable brown or gray stick mimic with characteristically thickened abdomen. Head flattened with white and black streaks that may continue onto thorax. First 2 pairs of legs appressed; third pair often held away. Fourth to eighth abdominal segments greatly thickened; dorsum and sides of fourth and fifth segments raised. Ventral margin between abdominal and anal prolegs with sparse fringe of light setae. Food: maples, oaks, poplars, and other forest trees. Caterpillar: June to October; 1 or 2 generations.