There are 8 species of Heteroceridae in Britain, all 2-5mm long with fossorial legs and pubescent elytra.  Most species are restricted to saltmarshes, although others live in the banks of rivers and ponds.  Adults live in shallow tunnels that they dig through bankside mud, but also fly well and come to light. 

The beetles are elongate, with an obvious waist between the pronotum and elytra, which usually have a variegated pattern of light yellow-brown interspersed with dark brown.  All members of the family are virtually impossible to reliably determine on outwards appearance, and almost always require dissection of the males.