The deathwatch beetle, Xestobium rufovillosum, is a species of woodboring beetle that sometimes infests the structural timbers of old buildings. The adult beetle is brown and about 7 mm (0. 3 in) long. Eggs are laid in crevices in old wood inside buildings, and the larvae bore their way into the timber, feeding for up to ten years before pupating, and later emerging from the wood as adult beetles. Timber that has been damp and is affected by fungal decay is soft enough for the larvae to chew. They obtain sufficient nourishment by using a number of enzymes present in their gut to digest the cellulose and hemicellulose in the wood.