(the following is curtesy of DWC)
Principally confined to the Southern and Central counties of England , the Death Watch Beetle attacks sapwoods and heartwoods of partially decayed hardwoods, mainly Oak, Elm and Chestnut. It will rarely attack softwoods when in contact with other affected hardwood timbers.
Dampness is essential for establishment and development although slow damage may occur in dryer timbers. Where the ends of timbers are embedded in damp walls, damage may be extreme. If the attack is on timber affected by fungus the entire centre of a large section of the beams may be hollowed out.
Adult insects are 6-9mm long, a chocolate brown colour with patches of yellow hair, and may be found on or under damaged timber in March or June particularly in warm weather, when they may be heard "tapping". This is the sound of both sexes hitting their heads on timbers during the mating season. [NOTE: Some who hear this sound coming from within the walls of their homes believe it portends death.] The flight holes of the emerging adult are usually 3.0mm in diameter.
The larva is pale cream in colour and has a thin dark line above the mouth parts, three small pairs of legs and is covered in gold hairs. It may be found under severely damaged timbers and may be present in affected timbers for up to 5 years.
Tunnels up to 3mm diameter are often extensive and of random orientation, mainly in the direction of the grain.
The bore dust is cream disc or bun shaped pellets, gritty when rubbed between the fingers