The deathwatch beetle, Xestobium rufovillosum, is a woodboring beetle. The adult beetle is 7 millimetres (0.28 in) long, while the xylophagous larvae are up to 11 mm (0.43 in) long.
To attract mates, these woodborers create a tapping or ticking sound that can be heard in the rafters of old buildings on quiet summer nights. They are therefore associated with quiet, sleepless nights and are named for the vigil (watch) kept beside the dying or dead, and by extension the superstitious have seen the death watch as an omen of impending death.
The term “death watch” has been applied to a variety of other ticking insects including Anobium striatum, some of the so-called booklice of the family Psocidae, and the appropriately named Atropos divinatoria and Clothilla pulsatoria.
The larva is very soft, yet can bore its way through wood, which it is able to digest using a number of enzymes in its alimentary canal provided that the wood has experienced prior fungal decay.