There is a main brood, flying mid May and June, with a second brood flying in August and September.
The larval food plant is Horseshoe Vetch.
The female is very similar to a female Chalkhill Blue but usually has some blue in the otherwise white discs surrounding the spots near the hind-wing margins. In the case of the female photographed on 26 August 2012, it is difficult to see the blue shading, but the insect was with a male Adonis Blue, they were both fresh, presumably second brood butterflies, and the remnants of the single brooded Chalkhill Blues flying that day were all very worn.