; subclass Pterygota, order Coleoptera)
Family of small, dark, cylindrical beetles, usually less than 5 mm long, in which the head is hooded by a large pronotum. The antennae are short and clubbed. The elytra are often incised and grooved behind, producing a device that enables them to shovel wood debris. An egg chamber is excavated under bark or deeper in wood according to species; eggs are placed in separate niches. Larvae are fleshy and legless, and tunnel away from the main chamber producing a characteristic pattern. Dutch elm disease is caused by a fungus carried by the elm-bark beetle, Scolytus scolytus; the fungus blocks tree vessels. Ambrosia beetles (e.g. Xyleborus species) penetrate wood, but larvae feed on fungi which develop on tunnel walls.
Subjects: Zoology and Animal Sciences.