Ottawa (Dunrobin), ON Canada

28 April 2007   9:29PM EDT  (top)
2 April 2007   10:32PM EDT  (center left)
22 April 2007   10:04PM EDT  (center right)
19 April 2007   9:38PM EDT  (bottom left)
1 April 2007   10:54Pm EDT  (bottom right)

Phigalia strigataria, sometimes called the Small Phigalia, is one of two species of Phigalia recorded from the Ottawa area (J. D. Lafontaine, pers. comm., 2001). My initial identifications were based on Covell (1984) and Handfield (1999).  Some information on the species has also been obtained from McGuffin, W.C., "Guide to the Geometridae of Canada (Lepidoptera), II.  Subfamily Ennominae.  2", Memoirs of the Entomological Society of Canada, no. 101 (Ottawa: 1977).

The forewing of the male Phigalia strigataria is medium gray, in fresh specimens often slightly greenish.  Antemedial, medial and postmedial lines are dark gray, often with thickening where they cross the most prominent veins.  The lines often have gaps, but are consistently evident close to the costa and at the inner margin.  The medial and postmedial lines are very close together at the inner margin, often appearing to touch where the lines thicken on the vein.  The postmedial line usually shows a double zigzag just below the costa.  On many specimens, a finely zigzag subterminal line is also present, although this line too may be faint or incomplete.  Often the most prominent vein running through the center of the wing is highlighted with whitish scales in the medial area (see photo at center left).  The hindwing is slightly paler, often with a faint medial line visible.  According to the literature, melanic specimens may be encountered, in which the entire wing is blackish, but these appear to be unusual at my location.  McGuffin (1977) notes a wing expanse of 28 to 35 mm.

The female Phigalia strigataria is flightless, with virtually non-existent vestigial wings.

Although the male Phigalia strigataria has some similarities to the male Phigalia titea, the two can usually be distinguished on the basis of P. strigataria being slightly smaller and darker gray, with medial and postmedial lines nearly touching or touching at the inner margin.  Also, live specimens of P. strigataria usually exhibit less hindwing when in a resting position than P. titea.

According to Handfield (1999), the larva of Phigalia strigataria has been reported to feed on elm. For my general area, he indicates the adult moth flies from early April to mid-May.

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