Lunar Marbled Brown Drymonia ruficornis
Wingspan 35-40 mm.
Similar to the Marbled Brown (D. dodonea), this species has a black crescent in the white area of the forewing.
Flying slightly earlier in the year than the former species, it is on the wing in April and May.
Inhabiting deciduous woodland, it is relatively common in the southern half of Britain, uncommon elsewhere.
Oak (Quercus) is the foodplant of the caterpillars.