Great Arctic (Oeneis nevadensis) (C. and R. Felder, 1866)
Diagnosis: The upperside is bright brownish tan, with darker brown wing borders. There are one to three black eye-spots with white pupils on the forewing and usually one on the hindwing, all repeated on the underside. The male has a large dark sex mark near the forewing costa. Beneath, the hindwing is finely striated in brown and grey, with an indistinct, irregular dark medial band. The hindwing margin has a series of white patches that gives the border a scalloped appearance. Wingspan: 50 to 60 mm.
Subspecies: There are three subspecies, two of which occur in Canada. The nominate subspecies (nevadensis) occurs on the British Columbia mainland; subspecies gigas, which is larger and has a darker hindwing underside, occurs on Vancouver Island.
Range: Oeneis nevadensis ranges from California into southwestern British Columbia, as far north as the Lillooet area.
Similar Species: Macoun's Arctic (O. macounii) males lack the dark sex patch on the upperside; they tend to have a more distinct hindwing medial band, but this is variable. Females of the Great Arctic and Macoun's Arctic can be difficult to identify in central British Columbia, where the ranges of the two species approach each other, and are the source of many misidentifications in this area. Females of Macoun's Arctic tend to have a more prominent, darker medial band on the hindwing underside than those of the Great Arctic and the pale striations on the outer third of the wing are less prominent and grey rather than white. The Chryxus Arctic (O. chryxus) is smaller and has distinct striations and white-lined veins on the hindwing underside. [compare images]
Early Stages: The larva has a black dorsal line and whitish, tan, brown, and black lateral lines; the head has six dark stripes. Food plants are unknown, but the larvae eat grasses in captivity (Scott,1986).
Abundance: Locally common in British Columbia.
Flight Season: The Great Arctic flies from late May to mid-July; it is found almost exclusively in even-numbered years.
Habits: It is most commonly seen around forest edges and clearings, and on rocky hills. It has a rapid, jerky flight and seems to disappear when it lands on tree trunks (Dornfeld, 1980). On Vancouver Island males tend to congregate on hilltops.
© 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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