Just on the subject of euryale, here is a shot (21990) of a selection puddling in the Hautes Alpes this year. There were hundreds of them, and I think you can just about see from this photo the variation in the white unh markings, although most were virtually unmarked. So it’s not necessarily a geographical or seasonal variant.
Nick’s second
Erebia is slightly puzzling (at least to me). The forewing outer margin is heavily rounded in a way that is characteristic of
melampus, which is probably definitive proof. However, the upf red post-discal band is pretty much continuous whereas the band for male
melampus is usually clearly divided by the veins, sometimes even into nice discrete red oval or bullet-shaped segments; I have a number of photos from the Valais this year and all fit this pattern. I have also seen male
melampus with an almost continuous but fuzzy-edged band in Vaud this year. The band here looks more like what I would expect from
epiphron aetheria.
Also, the pin-prick blind (i.e. no white centres) ocelli are in s2, s4 and s5. This diagram shows where:
http://www.butterfliesoffrance.com/wing%20diagram.htm (the diagram is reproduced with permission from Tristan Lafranchis). Usually I find that
melampus, if it has an ocellus other than s4/5, has one in s3 rather than s2, and that
aetheria has one in s2 rather than s3.
Of course,
Erebia being unhelpful little butterflies, they always settle in the grass making both ID and photography very difficult. In this case, a clear sight of the hindwing would help enormously as
aetheria often has a clearly angled margin (as in 23052).
I would not disagree with Guy if he was certain it was
melampus. There is no substitute for local knowledge.
Thanks to the lousy weather I obviously have too much time on my hands!
PS Gatekeepers don't occur in Var in the Mediterranean region.