Length 4 to 5 mm. Drymus is one of several lygaeid genera in which the front femur has one larger tooth and several small ones; it is rather a difficult genus to identify. In D. sylvaticus and D. ryei the tibiae lack long erect hairs and the scutellum and pronotum are entirely black.  In Drymus ryei, the forewings usually do not reach the end of the abdomen. 

Other Drymus

Detailed examination of the specimen is needed to identify the species.

Found amongst moss, grass and leaf-litter on dryish soils, probably feeding on a range of plants.

All year round

Common (ref.: British Heteroptera checklist 2021 on British Bugs website) 

Occasionally recorded

https://www.britishbugs.org.uk/heteroptera/Lygaeidae/Drymus_ryei.html