Persius Duskywing
Erynnis persius (Scudder, 1863)

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Diagnosis: This small greyish-brown duskywing has the four white flecks on the costa smaller than in similar species and arranged in an almost perfectly straight line at right angles to the costa. There is a grey patch in the central area of the forewing. The upperside of the forewing is covered by numerous raised white hairs. Wingspan: 24 to 31 mm.

Subspecies: Four subspecies have been named, but we recognize only two. The nominate subspecies persius is (or was) found in southern Ontario, and subspecies borealis, described from the North Nahanni River, Northwest Territories, occurs in the north and west.

Range: The nominate subspecies is found in the northeastern U.S. and extreme southern Ontario. Subspecies borealis is found throughout the western U.S., usually in the mountains, north through all the western provinces to Yukon and the Northwest Territories, almost to the Arctic Ocean in the Mackenzie Delta, and east to the west side of James Bay.

Similar Species: The Columbine, Wild Indigo, and Afranius Duskywings (E. lucilius, E. baptisiae, and E. afranius). [compare images]

Early Stages: Larvae are very similar to those of afranius, but the head is yellowish to reddish brown. Foodplants are reported to be various Fabaceae and Salicaceae. In southwestern Ontario the only foodplant is Wild Lupine (Lupinus perennis). On the Prairies poplar and willow have been reported as foodplants, but its utilization of these needs confirmation.

Abundance: It is fairly common in northern and western Canada; very rare, possibly extirpated, in southern Ontario.

Flight Season: The single generation flies from mid May to late June on the Prairies, mid-June to early August in the mountains and in the north.

Habits: This species is usually found in open forests, forest clearings, or along roadsides in forested areas. On the Prairies it is restricted to wooded ravines; it is replaced by afranius in open prairie habitats.

Remarks: Erynnis persius has not been reported from the area around St. Williams in southern Ontario since 1987, despite intensive searching where colonies previously existed. Some of these localities, and the foodplant, were shared with the Melissa Blue (Lycaeides melissa) and the Frosted Elfin (Callophrys irus), which are also probably extirpated from Ontario. All three species appear to be victims of problems with land management, especially habitat alteration.

© 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.

The Toronto Entomologists' Association thanks Agriculture and Agri-Food Canada for providing the content and computer code for this web page.