Arctic White (Pieris angelika) (Eitschberger, 1981)
Diagnosis: The Arctic White is smaller (wingspan: 33 to 42 mm) than the Mustard White (P. oleracea) and replaces it in the mountains of western Northwest Territories and Yukon. Males are mostly white above, with the forewing not as rounded as in the Mustard White, and there is a thin black line on the costa and the outer margin, with black shading extending in from the margin on the veins; on the underside the hindwing and the apex of the forewing are pale yellow, with the veins lined with dark blackish green. Females occur in white and pale yellow forms and have extensive black scaling over the veins on the upper surface, with dark patches near the middle of the wing and along the posterior margin.
Subspecies: The nominate subspecies, described from Keno, Yukon, occurs in Canada.
Range: The Arctic White occurs throughout Yukon and northwestern Northwest Territories, into northwestern British Columbia, and across Alaska.
Similar Species: The Mustard White (P. oleracea) is larger, has more rounded wings with little darkshading on the upperside, and the veins on the underside have narrower, more sharply defined darklines. The Margined White (P. marginalis) does not have the thin dark line on the outer margin of the wings in the males, and in both sexes the dark lines on the veins on the underside are paler and more diffuse than in angelika. [compare images]
Early Stages: These are still unknown.
Abundance: Pieris angelika is common in Yukon, but is uncommon in western Northwest Territories and in northwestern British Columbia.
Flight Season: There is one generation per year, with adults flying from late May until late July.
Habits: The Arctic White is found from moist woodlands and adjacent open areas to alpine tundra above treeline.
Remarks: The scientific name of the Arctic White is likely to change in the future. There are a number of names older than Pieris angelika Eitschberger, 1981 in the literature from Alaska and adjacent Siberia that may apply to this species and take precedence over this name. The number of species involved in northwestern North America and eastern Eurasia is unresolved, as is the application of names to the species involved.
© 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.
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