On a visit to the Var in France, this was one butterfly species which was really hoped for. We saw a few but many were towards the end of their days. The right side example shown however, was in rather better condition, and eventually paused for our photographs. 

I found the resemblance of the open hindwing pattern to be very reminiscent of the head on view of a small bird of the Parus family, I would guess no coincidence. Unfortunately to the right, the best shot I have does not display this feature. Below however, you may see what I mean.