Length 4.5 - 5.5; females larger than males.  Sexually dimorphic and variable in colouration and intensity of markings. Nymphs cannot be verified.

Males have dark scutellum with yellow spots towards apex and dark veins on forewings, with hyaline cells often with smoky suffusion at the apex.  Males usually have extensive dark markings on the face with prominent discoidal spots extended into two dark streaks down the face, but this is variable.  Examination of male genitalia (pygofer appendages) will separate from O subangulata.  There are several female colour forms; a common form has a yellow-green face and foreparts, but they can also be brown all over.  The shape of the ovipositor is shorter and more curved than O subangulata.

Other Oncopsis, including O. subangulata also associated with Birch; the two species are often found tgether

Detailed examination of the specimen is needed to identify this species. Clear photographs of the face should be provided. You must note the host plant.

On Birch

Adult: May to September

Common. (ref.: UK Auchenorrhyncha checklist 2021, on British Bugs website)

Occasionally recorded; probably common in suitable habitat

https://www.britishbugs.org.uk/homoptera/Cicadellidae/Oncopsis_flavicollis.html