Yeah, sorry I forgot to give details of where I saw it. It was in central Spain and the date was 5 September so would that explain the degradation? What mystified me was the strange overall shape, very tall and thin.
Yep, I would agree with markster2000 - male Grayling. He's looking tall and thin as he's lost the best part of his hindwings. This is usually down to birds and to some extent fighting with rival males. It always surprises me how much wing butterflies and moths can lose and still maintain reasonably accomplished flight - I have seen butterflies in the tropics flying on little more than stumps.
Thanks both of you. That is certainly very interesting information about how little wing a butterfly needs to be airborne. I used to fly light aircraft and I can tell you I wouldldn't consider taking off if even the smallest bit of my wing was missing.