Common Wood-Nymph (Cercyonis pegala) (Fabricius, 1775)
Diagnosis: Cercyonis pegala is a dark-brown butterfly with rounded wings. Females are a little lighter in colour and a little larger than males. On the forewing, on the upper- and undersides, there are two prominent eye-spots, each with a white pupil. In western North America the two spots are equal in size in pegala, or with the lower one larger. On the hindwing, there are up to three small eye-spots above and up to six on the underside, with females often having none. Wingspan: 38 to 58 mm.
Subspecies: Thirteen subspecies have been named, but in Canada the species forms a continuous line throughout its range. Dark specimens from the northern part of the range are usually called subspecies nephele; specimens from the eastern U.S. (subspecies pegala) have a large yellow patch on the forewing that surrounds the two black eye-spots; varying amounts of yellow (occasionally as much as in subspecies pegala are evident in specimens from eastern Canada. Western specimens have been treated as subspecies ino (in the Prairies) and boopis (in southern British Columbia), but these are probably not sufficiently distinct from nephele to warrant subspecific recognition; we retain them until the genus is revised.
Range: The Common Wood-Nymph is found throughout the U.S., except in the southwest. In Canada it is found in every province except Newfoundland, north to St-Felicien, Quebec, Keewatin, Ontario, Thompson, Manitoba, Meadow Lake Park, Saskatchewan, and the Peace River District of Alberta and British Columbia. There is an area north of Lake Superior, between Sault Ste. Marie and Marathon, where it is apparently absent.
Similar Species: The Small Wood-Nymph (C. oetus) and the Great Basin Wood-Nymph (C. sthenele) are smaller, and oetus has more pointed forewings. In both species the second eyespot (closer to the hind margin of the forewing) is smaller than the other spot, or is absent. [compare images]
Early Stages: The larvae are green, yellowish green near the posterior end, with two reddish tails; there is a dark green dorsal stripe and one or two pale lateral stripes, and the head is green. They feed on various grasses, including Wild Oats (Avena fatua), Purpletop Grass (Tridens flavus) and bluestem (Andropogon spp.), and overwinter as the first instar.
Abundance: The Common Wood-Nymph is common over most of its range.
Flight Season: It flies from late June to early September, lasting about five weeks in most areas; there is one generation per year.
Habits: The common name "Wood-Nymph" is something of a misnomer, for the species is not associated with woodland. It frequents open flowery meadows and roadsides, usually in dry areas. It is regularly seen nectaring on flowers to a much greater extent than most satyrids.
© 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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