About Colias alfacariensis Ribbe, 1905
Males of Colias alfacariensis have wings with a yellow ground colour, while females have a greenish-white ground colour; only the underside of the hind wings is yellowish in both sexes. The upper side of the wings of both sexes has a dusted dark brown to black marginal band, which is narrow only on the hind wings. A black spot is present in the cell of the forewings on both the upper and lower sides. On the upperside of male hindwings, the cell holds an orange spot with a red border; on the underside this spot is bright and clearly outlined in red. The red border may divide this spot into two, making it resemble the number eight, just like in Colias hyale and other yellow members of the genus Colias. In females, the orange spot on the upperside of the hind wings has no border. After their second moult, Colias alfacariensis caterpillars are clearly distinct from Colias hyale caterpillars. Both species have green caterpillars, but Colias alfacariensis caterpillars have four prominent yellow lines marked with black dots, while Colias hyale caterpillars have only two thin side lines. Colias alfacariensis forms a species complex with Colias hyale. Because butterflies of both species have many variations, the two cannot be distinguished by morphology or genitalic examination. Information about habitat and geographical distribution only provides an indication of which species an individual may belong to, and a reliable distinction can only be made using their fully different caterpillar forms. Other similar species are Colias crocea, Colias phicomone, Colias palaeno, Colias chrysotheme, and Colias erate.
