Mead's Sulphur (Colias meadii) (W.H. Edwards, 1871)

Diagnosis: This striking sulphur is deep orange on the upperside with a wide, dull black border. Males have a distinctive oval, paler orange patch on the leading edge of the hindwing upperside near the base. This is frequently hidden under the lower margin of the forewing. The female has light spots in the border and occasional white specimens are encountered. The underside is greenish yellow with a thin pink rim around the central silver spot and no submarginal spots. Wingspan: 35 to 44 mm.

Subspecies: Only subspecies elis is found in Canada. The type locality is Kicking Horse Pass, Alberta.

Range: Mead's Sulphur appears to be restricted to the front range of the Rocky Mountains in Canada and in scattered colonies through the Rocky Mountain region in the U.S. Reports from Pink Mountain in northern British Columbia are believed to be misidentified Hecla Sulphur (C. hecla) or Christina Sulphur (C. christina) (Curtis and Ferris,1985).

Specimen collection data

Similar Species: In its restricted alpine range in Canada, Mead's Sulphur is likely to be confused only with the Canada Sulphur (C. canadensis), although the Orange Sulphur and Christina Sulphur (C. eurytheme and christina) can also occur nearby. All are paler orange in colour, have narrower black borders, and lack the pale patch at the base of the hindwing in males. Only the Johansen's Sulphur (C. johanseni) is very similar to meadii; see Johansen's Sulphur Remarks. [compare images]

Early Stages: The larvae are yellow green with many black dots and a pale yellow lateral stripe. There is some speculation that they over winter twice before pupating (Scott, 1986). They feed on alpine legumes.

Abundance: This tends to be a local and generally uncommon species. However, in a few known locations it can be common for a short period of time.

Flight Season: There is only one brood in midsummer, usually in July and August, but the season is brief at any one locality.

Habits: You have to be high up in the mountains, near or above the timberline to see Mead's Sulphur. It is most often seen in alpine meadows and on high windy ridges, where it uses its dusky undersides to soak up the sun's warmth. The deep orange upperside and dusky-green underside make it difficult to follow as it suddenly alights in the grass out of the alpine winds.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.