The adult beetle is cinnamon brown, gray underneath, with white at the sides. Each wing cover has a crescent-shaped, white spot at middle, and a smaller circular one near the apex. These spots may be faint or missing, usually in the male. The antennae are darker than those of S. cretata . The beetles fly little, are sluggish, and quickly drop to the ground when approached.
Egg laying probably occurs at night, often on the same tree the beetles inhabited as borers.
An egg is deposited in each slit, and the hatching larvae tunnel into the wood. The wandering and feeding cause the gall to form. The larval galleries parallel one another for 2 to 3 inches in the center of the twig. Pupation takes place within the twig. A round exit hole is cut at right angles to the larval burrow.