Ottawa (Dunrobin), ON Canada

8 July 2004   10:17PM EST  (top left)
22 July 2004   12:28AM EST  (top right)
16 July 2004   9:38PM EST  (bottom)

Polia imbrifera, sometimes called the Cloudy Arches moth, is one of several species of Polia recorded from the Ottawa area (J.D. Lafontaine, pers. comm., 2001), three of which are illustrated on this website.  My thanks to Mr. J.T. Troubridge of Agriculture Canada for confirming my identification of the specimen illustrated at top left above.

The forewing of Polia imbrifera is predominantly light brownish gray with variable darker shading.  The double scalloped antermedial and postmedial lines are most distinct near the inner margin.  The dark-filled orbicular, claviform and reniform spots are evident, but their outlines may be somewhat indistinct  Inside the subterminal line, there are small areas of very dark shading near the midpoint of the outer margin and near the anal angle.  A squarish patch at the apex is somewhat lighter gray than the rest of the forewing. The hindwing is grayish brown, with a band of dark shading between the fine dark median line and the outer margin. Covell (1984) indicates a wingspan from 4.0 to 5.3 cm for this species.

According to Handfield (1999), reported host plants for Polia imbrifera include chokecherry, willow, some birch species and alder. For my general area, he indicates an adult flight season from the later part of June to late August.

My records to date for Polia imbrifera (each date representing "the night of") are in the table below: