Buff-tip Phalera bucephala
Wingspan 42-55 mm.
When at rest, the adults of this species bear a remarkable resemblance to a broken twig of silver birch.
The species is widely distributed throughout Britain, and quite common, especially in the southern half.
The yellow-and-black caterpillars live gregariously and feed on a number of different deciduous trees, sometimes defoliating entire branches.
The adults fly in June and July, frequenting mixed woodland.