Ottawa (Dunrobin), ON Canada

11 April 2005  (moth captured on 6 April 2005)  (top left)
1 April 2005   1:40AM EST  (top right)
6 April 2005   8:27PM EST  (bottom)
The photos at top left and bottom are of the same specimen.  The weather had been quite rainy on 6 April 2005, and it was clear that this specimen had been quite wet, as evidenced by the bedraggled appearance of the thorax and fringe.  I was very surprised, therefore, when I re-photographed the moth a few days later, to see that a more pristine appearance of the thorax and fringe was restored when it had dried out again.

Eupsilia tristigmata is one of four species of Eupsilia that have been recorded from the Ottawa area (J.D. Lafontaine, pers.comm., 2001).

Eupsilia tristigmata has a reddish brown forewing, usually more red-orange than in the similar Eupsilia vinulenta (Hodges 9933).  All the usual lines are evident, usually in a darker purplish brown that contrasts with the lighter background color.  The median area is usually a slightly more intense color than the rest of the forewing; the terminal area is also often darker.  There is also a darker shade just inside the subterminal line.  The orbicular spot is evident as a slightly paler reddish brown filling inside a darker brown circle.  There is also usually a "drip mark" of paler filling outlined with darker brown "hanging" outside the am line about halfway between the orbicular spot and the inner margin.  The reniform spot may be white or orange, with white dots above and below, with a pronounced dark blotch around the lower dot.  I tend to distinguish E. tristigmata visually from E. vinulenta (Hodges 9933) on the basis of the reniform spot, which in E. tristigmata always appears to have an orange-filled crescent along the inner side, which is lacking in E. vinulenta.  A median band of darker brown is often evident, forming a shallow V with its point at the dark-blotch end of the reniform spot.  The hindwing is a fairly dark grayish brown with pale fringe.

Eupsilia tristigmata is superficially similar to several other species of Eupsilia, one of which (E. vinulenta, Hodges 9933) occurs in the Ottawa area.  Fortunately, it is possible to distinguish between E. vinulenta and E. tristigmata by looking at the scales under a microscope, where the scales of E. vinulenta are seen to end in four small straight teeth.  There are also other visible differences between these two species, as mentioned above, but sometimes these are inconclusive, especially in a worn or damaged specimen.

The larvae of Eupsilia tristigmata feed on many trees and shrubs, especially willow, poplar and birch (Handfield, 1999).  According to Handfield, this species overwinters as an adult, with flight seasons in my general area from the later part of March to mid-May, and from mid-September into the second half of October.

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