Erebia pluto - Sooty Ringlet
Another one I yearned to see, intrigued by information it was to be found in the highest parts of scree covered mountain tops, and indeed it proved so. These were photographed with quite a lot of difficulty at the top of Bormio 3000 in Italy.
Easily spooked, and flying a distance before re-settling, it was hard to get even within 3 metres of them.
So, they are some of my most highly prized butterfly photographs.