Leiodidae (fungus beetles)
Duff's key to subfamilies relies on ascertaining the presence or absence and, if present, position of the occipital crest. I've struggled a little to work out what he means here and see it on the specimens I've examined, so personally I find Mike Hackston's key easier to use at this stage. So far I think I've found Duff straightforward enough to use once I've got it to subfamily.
Leiodes litura
Leiodes cinnamomea
Choleva angustata
Ptomaphagus subvillosus