Adults have a wingspan of 24–28 mm, with male specimens generally slightly smaller and darker than females.[2] It is primarily nocturnal, but it will occasionally fly in the daytime. The moth usually flies between June and July.[1]
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Biology
The festoon mainly inhabits thick woodlands. The larvae are known to feed on oak and beech.[1]
Life cycle and behaviour
The larva is small and grub-like. After storms, caterpillars are often observed in large numbers between August and October. Cocoons are not attached, but overwinter and pupate in the spring.[1]