Dreamy Duskywing (Erynnis icelus) (Scudder and Burgess, 1870)

Diagnosis: This relatively small duskywing (wingspan: 23 to 30 mm) has a dark-edged purplish-grey band across the forewings, and occasionally an obscure second band closer to the base of the wing. It lacks the white spots on the forewing typical of most duskywings.

Range: Found across southern Canada from Cape Breton to Vancouver Island, north to Opinaca River, Quebec, Attawapiskat, Ontario, Lynn Lake, Manitoba, and Norman Wells, Northwest Territories. It also ranges well down into the eastern and western U.S., but is mainly absent from the plains.

Similar Species: The Sleepy Duskywing (E. brizo) is the only other Canadian duskywing without white forewing spots. In brizo the outer dark band tends to be more distinct and often partly broken and chain-like, and the second band is much more distinct. Even where the ranges of the two species overlap, they can usually be separated by habitat preference, with icelus in moist willow/poplar woods and brizo in dry oak woods. They are not easy to separate by pattern, though there are good genitalic differences, and males of brizo lack the hair plume on the hind leg. [compare images]

Early Stages: The larvae are pale green, with a dark dorsal stripe and paler lateral stripes; the head is black with two large brown patches. They live in leaf-nests on the foodplants, which include various species of poplar, aspen, willow, and birch.

Abundance: Erynnis icelus is common around woods edges and clearings, especially in damp areas where willows are most common.

Flight Season: One generation, mid-May to late June, in the south, but it flies well into July farther north.

Habits: The Dreamy Duskywing is often seen at flowers, but more often lands on the ground, in sandy or muddy areas.

© 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.