A customer of mine found these little beetles in her house. Any idea what they are? They come out from between the wall floor junctions of the downstairs rooms in a terrace house. The house has no known other issues like damp etc. Why would these beetles be in her house?
The first beetle is larger and abit squashed!
The second beetle is slightly smaller and leaner looking (the male?)
These are adults of the wharf borer beetle, Nacerdes melanura, (Coleoptera: Oedermeridae) - the larvae feed on buried and sodden timber, which can include those associated with wharfs but also demolished building timbers. I would say that somewhere below the boards there are rotten timbers, though not necessarily associated with the build of the house.