Eversmann's Parnassian (Parnassius eversmanni) (Ménétriés, 1851)
Diagnosis: This butterfly differs from the other North American parnassians by its ground colour, which is yellow in the male and yellowish white in the female. It also has black antennae, which distinguishes it from Parnassius phoebus. The red central spot on the hindwing is attached by a blackbar to the spot near the inner margin of the wing. Wingspan: 46 to 54 mm.
Subspecies: Only subspecies thor is found in North America.
Range: Mainly Asian and Alaskan in distribution, the range of eversmanni extends into Canada in the mountains of Yukon and northern British Columbia.
Similar Species: The other North American parnassians lack the yellow ground colour of the wings in males, and the red spot in the centre of the hindwing is surrounded by a black outline, but is not connected to the other red spots as in eversmanni.
Early Stages: The larva feeds on Corydalis spp. (Fumariaceae) and is black with short hairs and yellow to white spots and dashes on each segment. It takes two years for the larvae to reach maturity and the adults to emerge.
Abundance: Because of its habitat preference for mountainous tundra areas, eversmanni is not often encountered in Canada. It is very localized and is usually found where Corydalis is common. Its North American range closely matches that of Corydalis pauciflora.
Flight Season: There is one brood with adults emerging in June and July.
Habits: The adults fly low and fast over open ground and rocky slopes in protected areas between hills or in stream valleys, where they fly among shrub willows.
© 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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