Ianassa pallida (Strecker, 1899)
Pale Prominent Moth
View Photographic Plate
WA : Okanogan Co.
Harts Pass Rd. @ Deadhorse Pt., 3841 ft
July 23, 1997, L. G. Crabo.
Specimen courtesy of LGCC
Photograph copyright: Merrill A. Peterson
Ianassa pallida is a medium to large, prominent moth (FW length 18–23 mm.) with light orange-brown forewings with lighter whitish gray toward the apex. The forewings are long with scalloped outer margin. The ordinary transverse lines are faint brown, obsolete near the posterior margin. A brown mark is also present at the anal angle. The discal spot is a thin black bar, the black continued on the veins distal to the cell. Other black markings include a thin basal dash and two lines at and adjacent to the subapical costa. The male hindwing is pale yellow brown with dark brown at the anal angle; that of the female is darker brown gray. The thorax is silvery brown and dark orange brown with weak posterior tufting. The antenna is bipectinate, tapering toward the tip; those of the female are simple.
This species is can be identified by its color and black bar-shaped discal spot. It is most likely to be confused with Oedemasia semirufescens, but this species is pale blue-gray and pinkish brown and lacks the black discal spot of I. pallida.
This species is placed in the genus Ianassa Walker in a recent check list of the New World prominents by Becker (2014), having previously been placed in the genus Oligocentria Herrich-Schaeffer.
This species is usually uncommon in most areas, but is widely distributed in forests throughout the Pacific Northwest. These habitats include coastal rainforests, mixed hardwood forests west of the Cascades, and mixed hardwood-conifer forests at higher elevations in the Cascades, Blue Mountains, and Rocky Mountain region.
Ianassa pallida is widely distributed in forests of the Pacific Northwest, including along the Pacific Coast. It does not occur in xeric steppe habitats.
This species occurs throughout much of western North America as far north as southern Canada.
No information is currently available regarding larval foodplants, but it probably feeds on hardwoods based on closely related species.
Ianassa pallida appears to be single brooded and is most commonly found in July. Pacific Northwest collection records span late May to early September. It is nocturnal and comes to light. As with other prominent moths the adults do not feed.