Clouded Sulphur

Why not Colias eurytheme?

Thanks, bayucca -- it is, indeed, the clouded sulphur!

All of a sudden I am in doubt if this is really Colias philodice. Might also be Colias eurytheme. I Switzerland we have also 2 Colias sp., which are non-separatable, even with genital examination. The only reliable way would be going back to the caterpillar which looks VERY different. Maybe food plant might give some hints, but in my area this would also be tricky since you have to do it by exclusion, meaning again going back to caterpillar stage. maybe description of the habitat with predominant plants might help.
Colias philodice OR Colias eurytheme.