The powderpost beetles are well known by their exit holes, sometimes so numerous that the surface of the wood looks as if it had been riddled by a charge of birdshot. The most important group of insects that attack wood in this way includes 3 closely related families of beetles (Lyctidae, Bostrichidae, and Anobiidae).

The larvae of these beetles reduce wood to a mass of powdery or pelletized frass (powder). They attack dead wood almost exclusively, especially dried and cured lumber, and several generations can reinfest the same piece of wood until only the outer shell remains, riddled with little holes called “exit holes”. Beneath the surface of the infested wood are frass-filled galleries or tunnels, usually along the grain of the wood.

The damage caused by these 3 families of beetles can be identified as follows.

 - The True Powderpost Beetles (Lyctidae) loosely fill their galleries with very fine powder, similar in  appearance to face powder.

 - The False Powderpost Beetles (Bostrichidae) tightly pack their galleries with a coarser boring dust, often containing small wood fragments.

 - The Deathwatch Beetles (Anobiidae) fill their galleries with small pellets.

The frass in the galleries of the bostrichids and anobiids is not only coarser than that of the lyctids, but tends to stick together. Although all these beetles have sometimes been collectively referred to as "powderpost beetles," in a more definitive sense the term should apply only to the lyctids, for their larvae are the only ones that produce a fine, powderlike dust in their galleries.

Powderpost beetles cause more confusion than any other structure-infesting pest.
Homeowners often receive conflicting opinions as to whether the "damage" they are seeing is indeed done by the them. Mistakes also are made in determining if the infestation is active and if so, how it should be managed. Incorrect information results in unnecessary treatment and expense, or a failure to protect the client's property.

There are questions whether the damage seen had been caused by termites or beetles. Damage to wood caused by lyctids, bostrichids, and anobiids is likely to be first noticed when the round emergence holes of the adults are seen or the beetles are found on infested wood and the presence of powderlike frass. In the wood structure of the building, beetle infestations occur most often in hardwood furniture and flooring.

All of the adult lyctid and anobiid beetles are strong fliers and are attracted to light. They may, therefore, often be discovered at or near windows when an infestation occurs in a room. Even experienced entomologists often mistake the furniture beetle, Anobium punctatum, for a fly, since in flight it closely resembles the latter, even to the extent of flying around light bulbs.