Length 4 to 5 mm.  The four bugs in this genus are distinctively shaped and have a highly punctured body and forewings. However, they can be difficult to separate.  Cymus glandicolor has a pale keel on the scutellum, and dark markings on the cubital wing vein. These markings are roughly parallel to the edge of the forewing, pointing towards the base of the corium. 

In the similar but much rarer Cymus aurescens, these markings are more oblique to the wing edge and point towards it. The tibiae are usually pale.

Detailed examination of the specimen is needed to identify the species (a photograph alone is not normally sufficient because key features are too small or hidden).

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Found in damper habitats such as damp meadows, marshes and dune slacks, feeding on sedges.

Adult: All year

Found widely in England and Wales, and recently recorded from Scotland.

Probably under recorded in Leicestershire and Rutland.

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