Colias mating

[jmg]

Is this couple mating Colias hyale or another species like alfacariensis ? It was impossible to picture the upper face !

Nîmes le Vieux, 1100 m asl (Fraissinet-de-Fourques, Lozère, France), August 27, 2018



Many thanks in advance!

[bobw]

Whilst it's not too hard to separate hyale and alfacariensis from the upperside, I know of no way to separate them from the underside.  In general hyale has a more easterly distribution and alfacariensis more westerly.  Also, hyale is generally found at higher altitudes than alfacariensis, however; there are many exceptions to these rules.  Judging by the locality it could be either but on balance I would say alfacariesis is more likely.