The wingspan is 31โ37 mm. The length of the forewings is 15โ18 mm. Quite distinct from all other Palearctic species, the forewing light brown, the lines finely whitish, proximally dark shaded, subterminal line rather straight, sometimes indistinct.[2] The moth flies from the end of April to the end of June and are readily flushed from the foodpant or surrounding vegetation.[1] They are also attracted to light.[3]
Ova
The egg has an elliptical shape and is initially light yellow, later orange. It is covered with 24 to 25 longitudinal ribs. The microphyll rosette is nine to ten-leaf.
Larva
The caterpillars have a brownish or greenish colour, show fine dark longitudinal lines and a wide whitish or yellowish side stripe. They feed on bracken (Pteridium aquilinum) from about mid-June to early September, although most have pupated in the soil by late July.[4]
^Porter, Jim (1997). The Colour Identificatation Guide to the Caterpillars of the British Isles. Harmondsworth, Middlesex: Viking. pp. 60โ1. ISBN0-670-87509-0.