Riband Wave.
(Idaea aversata)

Nestling under a pile of egg boxes in the moth trap.

Information:
Fore-wing length: 14-16mm. The shape of the broad darker band as shown in the photo is typical but sometimes the 'band' is just two thin crosslines that follow the same pattern. The overall colouring is sandy brown.
They fly in June-August and sometimes in September-October and can be seen just about anywhere in Britain.