Ottawa (Dunrobin), ON Canada

27 August 2005   11:04PM EST  (left)
30 August 2005   12:09AM EST  (right)

My thanks to Mr. James T. Troubridge of Agriculture Canada for confirming my identifications of the specimens illustrated above.

Trichosilia geniculata, also known as the Knee-Joint Dart, has a gray forewing with darker gray and brown shading.  The antemedial and postmedial lines are double, filled with light gray, and clearly visible.  The gray-filled double basal line may also be visible.  The orbicular and reniform spots are gray, contrasting with a black shade extending from the am line slightly below the costa and filling most of the space beetween the two spots.  The median area below this black shade may be shaded with brown, becoming less shaded towards the inner margin.  The area between the pm line and the jagged irregular subterminal line is a darker, slightly brownish gray.  The fringe is gray, similar to the ground color of the wing.  The hindwing is whitish gray, shaded with brownish gray towards the outer margin.  Covell (1984) indicates a wingspan ranging from 2.9 to 3.4 cm for this species.    

According to Handfield (1999), the host plant for Trichosilia geniculata is unknown, but Covell (1984) suggests the larvae likely feed on a wide variety of plants. For my general area, Handfield indicates an adult flight season from the later part of July to mid-September.

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