The Oak Marbled Brown (Drymonia querna) flies from May to August.
The larvae feed on oak and also European beech.
They can be distinguished from other similar looking Drymonia species (like the Lunar Marbled Brown, Drymonia ruficornis) by having a usually overall darker colouration and by the white colour of the hind wings.

Caught in my self made moth trap.

In my yard, Hilversum, The Netherlands, 2 September 2018