Of all Drymus species Drymus ryeii is the darkest, the basic colour being described as black. The membrane parts of the front wings are darkened as well. In many animals, but not all, the edge of the front wings stand out, for they are much lighter in colour, usually yellowish. In the pictures this is clearly visible. Animals lacking this light edge are much more difficult to identify. Especially Brymus sylvaticus is a problem, for it may appear identical. The main difference is on the tibia: with hairs in Brymus sylvaticus, bald in Drymus ryeii. Another help may be the biotope: Drymus sylvaticus prefers dry areas, such as heath, while Drymus ryeii prefers more wet conditions, such as forests. The animal measures 3.7 to 4.7 mm.
Little is actually known about this species, especially about the food. According to some it sucks on mosses, while others presume it sucks on seeds. The fact is that both larvae and adults are mainly found on, in or under mosses. The first adults appear from August and overwinter. They mate in May or June and juveniles are seen till November. There is only one generation per annum.
This is a common species all over Europe and eastwards into Siberia. Common in England, rarer in other parts of the UK.