The male Clouded Yellow butterfly (above left and below left) is often brighter yellow than the female (above right and below right); both have a greeny-yellow tinge on the hind underside. They may have one white spot on the hindwing (above) or a main spot with one or more adjacent minor spots (below). There is also a red-pink spot and narrow red border. The
female Pale Clouded Yellow butterfly (Colias hyale) looks similar to the paler form of the female Clouded Yellow above (has no black border on topside of hind wing).
The Clouded Yellow never rests with wings open, but when the topside is visible, there is a thick black border which has yellow spots on the female above left and is continuous on the male.