Alba-form
Guides
Colias philodice
common sulphur, clouded sulphur
Colias philodice is a North American pierid butterfly commonly known as the clouded sulphur or common sulphur. It is a multivoltine species that produces multiple generations per year. Adults are typically pale yellow above with no orange traces, distinguishing them from the closely related orange sulphur (C. eurytheme). Females exhibit a white form (alba) that can be common in some populations. The species is a legume-feeder whose larvae primarily develop on alfalfa (Medicago sativa) and various clovers, making it economically significant in agricultural settings. It ranges across most of North America except for the far northern regions of Labrador, Nunavut, and northern Quebec.