short-tailed blue???

[Kip]

I puzzled over this Alpine butterfly when I got home, eventually concluding the best fit was osiris..... then I found this shot with a hint of visible underside if you expand and magnify it.... now it has not even vestigial tails, but what I can see of the underside suggests argiades.... anyone's opinion would be welcome please...

[Roger Gibbons]

I would say thersites is a strong contender.
Roger