Wingspan 17-20 mm.
Rather similar to other Apotomis species, there are subtle differences in the shape and markings on the forewing.
The species has a wide distribution throughout Britain, but is generally commoner in the north, where it frequents mosses and heaths on higher ground.
The adults are nocturnal and fly from May to July, coming to light.
Birch (Betula) is the foodplant, the larvae living between two leaves spun together.