The powderpost beetle is a dark brown or reddish brown shiny beetle, with the thorax usually appearing darker than the elytra. The body is flattened and elongated. The antennae are about the same length as the thorax , with the end segments forming a club shape. The elytra have a several ridges along the length. Larvae are cream c-shaped grubs with a brown head and light brown oval spots on the sides of the body. The bore holes of emerging adults are 1.5mm to 2mm in diameter.