Tenebrionid beetle (also known as mealworm beetle)

Habitat:

Very well rotted damp timbers. It may also damage timbers which are associated with infested flour.

Damage characteristics:

Irregular oval or circular tunnels up to 10 mm in diameter, partially filled with coarse, fibrous powder.

Insect characteristics and location:

Adults are occasionally found in buildings.

Larva up to 30 mm long, straight, pale yellowish. Three pairs of large, obviously jointed legs. Pair of small spines at rear end of the larva or obvious double hooks.