Lang’s Short-Tailed Blue butterfly

There’s a blue butterfly on a short flowering plant amongst the grass in Parco della Caffarella in Rome. It has antennae with fine black and white hoops:

I want it to turn round so I can get a decent photograph of it. There:

It has the most beautiful pattern on its underwings and short tails projecting out behind the ‘eyes’ on the wings. It’s Lang’s Short-Tailed Blue butterfly, Leptotes pirithous. It’s not a UK species, although a single individual was caught in Bloxworth in Dorset on 13 June 1938.

I’m so pleased to have seen it.

Now I just have to identify the flowering plant it’s on.