Clouded Sulphur - Colias philodice - male - in flight. These are very similar to the more common Orange Sulphur except for the latter's orange hindwing spot and lighter orange wash over most of both wings seen from above. Female Orange Sulphurs are less strongly marked with orange which sometimes makes separating female Orange and Clouded sulphurs difficult. Females of both species also have a white summer form in which they are even more difficult to tell one from the other.