Ottawa (Dunrobin), ON Canada

10 June 2005   (date of moth capture)  (top left)
22 June 2004   10:49PM EST  (top right)
8 June 2005   10:14PM EST  (bottom left)
10 June 2005   11:45PM EST  (bottom right)
The photos at top left and bottom right are of the same specimen. 

Spiramater grandis, sometimes called the Grand Arches moth, is one of two species of Spiramater known to occur in the Ottawa area (J.D. Lafontaine, pers. comm., 2001).

Spiramater grandis has a predominantly brownish forewing, varying from a reddish brown to a more grayish brown.  The upper half of the basal area is comparatively pale, and mottled gray and reddish brown above a black basal dash.  The double, scalloped antemedial and postmedial lines are filled with light gray, and typically most clearly marked in the lower half of the wing towards the inner margin.  The claviform spot is largely obscured by a black streak or dash running through the median between the am and pm lines.  The orbicular and reniform spots are outlined in black, rimmed with whitish on the inside and mainly filled with brown.  The area between the pm line and the whitish subterminal line is mostly filled with a band of grayish white.  The st line is edged with reddish brown and black along most of its inner edge, and angles sharply outward to form two points extending to the middle of the outer margin, in a shape resembling a W.  The hindwing is dirty yellowish gray in color, with some darker shading towards the outer margin and a fine dark terminal line.  Covell (1984) indicates a wingspan ranging from 3.1 to 4.5 for this species.

According to Handfield (1999), the larvae of Spiramater grandis have been reported to feed on poplar, willow, burdock, basswood, blueberry, alder, flowering dogwood, cherry and lambsquarters. For my general area, he indicates an adult flight season from the later part of May nearly to mid-July.

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