The Lunar Marbled Brown (Drymonia ruficornis) flies from April to June.
The larvae feed on oak exclusively.
They can be distinguished from other similar looking Drymonia species (like the Oak Marbled Brown, Drymonia querna) by the presence of a black crescent (shape of a half circle) just above the centre of the forewing and by the smoky grey colour of the hind wings.

Caught in my self made moth trap.

In my yard, Hilversum, The Netherlands, 21 April 2019