Ottawa (Dunrobin), ON Canada

18 July 2004   (moth captured on 17 July 2004)  (top)
17 July 2004   9:54PM EST  (bottom)
Both photos are of the same specimen.

Catocala unijuga, also termed the Once-Married Underwing, is one of 28 species of Catocala that have been recorded from the Ottawa area (J.D. Lafontaine, pers. comm., 2001). To date, I have observed 19 of these species at my location. Collectively, these are referred to as the underwing moths, for their often-colorful hindwings.

The forewing of Catocala unijuga is gray with whitish, gray and black markings. The double antemedial line is somewhat diffuse with pale gray to white filling. The inner half of the median is somewhat paler than the rest of the wing, with a whitish area preceding the reniform spot with its double dark gray outline in the dark gray median band. A somewhat angular subreniform spot is filled with pale gray to white. The inner edge of the postmedial line is quite sharp and black, and the sharp inward bend near the inner margin is plainly visible. The zigzag subterminal line is whitish, and the terminal line appears as a series of black dashes preceding the gray fringe. The hindwing is banded in deep orange-red and black, and has a white fringe. Covell (1984) indicates a wingspan of 7 to 9 cm.

Catocala unijuga is similar in appearance to two other species of Catocala, and identifications should be carefully checked.

According to Handfield (1999), the larvae of Catocala unijuga feed on poplar, in particular on trembling aspen, but also on other species of poplar and willow. He indicates an adult flight season from before mid-July nearly to mid-October for my general area. Despite the fact that this species is considered fairly common, it is one I seldom see.

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