"Blue" underside

[SimonC69]

Hi people. I'm hopeless at IDing certain Blues from underside only shots, some help with this one (with pointers to help me in future) would be appreciated
Taken 20th August on a site with both Adonis and Chalkhill Blues on the wing.

TIA.

[bugboy]

Well from that angle it has a 50% chance of being either, for me the only clue is the date. Being fresh in August this year moves the percentage to perhaps 70-80% Adonis (assuming the Chalkhills on this site were as early as they were on the ones I visited this year.)

[SimonC69]

Well, from what I could see, tha Adonis outnumbered Chalkhill by about 6-1 so that would make sense. Cheers