Would agree with Angle Shades Pete as they are the first sign of butterfly or moth I see in my garden every year.
Usually they munch into the early growning buds of Clematis but I can find then on Mint,Buddlia as well,they are definitely not fussy eaters.
Heres a couple of shots of mine.
The second shot is not a clothes eater I just moved it there.
They do also change colour as you can see in the UK Moths photo.
Cheers
Colin