Subfamily Pierinæ (the Yellows, Sulphurs, and Whites)
For the most part small or medium-sized butterflies, white or yellow in color, with dark marginal markings. The eggs are spindle-shaped, marked with vertical ridges and horizontal cross-lines. The caterpillars are cylindrical, relatively long, generally green in color, with longitudinal stripes. The chrysalids are more or less pointed at the head, with the wing-cases greatly developed on the ventral side, forming a more or less keel-shaped projection upon this surface.
The subfamily is very large, and is well represented in the tropics of both the eastern and western hemispheres. Certain genera are also widely distributed in the colder regions of both the north and the south, among them the genus Colias, species of which occur from Greenland to Patagonia and from the North Cape to the Cape of Good Hope.