Ottawa (Dunrobin), ON Canada

9 June 2002   1:32AM EST  (left)
10 June 2002   1:14AM EST  (right)

Furcula borealis is one of several species of Furcula that may occur in my area, several of which are quite similar in appearance.  Compare this moth with Furcula occidentalis (7939), also illustrated on this web site.  When I first encountered Furcula borealis in 2000, Covell's 1984 field guide was my only reference book, and I cheerfully labelled the photos as Furcula borealis, only to remove the label again in 2001 when Handfield's 1999 guide to Quebec moths informed me of the other similar species.  Eventually, in 2002, some much appreciated help from Jeff Crolla of Toronto and Dr. J. Donald Lafontaine of Agriculture Canada enabled me to sort out three Furcula species among my photographs.

Also known as the White Furcula, Furcula borealis shows a striking pattern of dark gray and white.  The medial area of the forewing is filled with dark gray, while the basal and subterminal areas are a glistening white in the few specimens I have photographed.  Basal, subterminal and terminal lines are represented by rows of black dots.  There is also blotch of dark grey at the costal edge just outside the subterminal line.  In both photos above, it is also possible to see a hint of rusty orange picked out along the outer edge of the dark gray median; the visibility of these specks of dark orange varies from one specimen to another.

There seems to be general agreement that the larval host plant is black cherry (Prunus serotina); poplar and willow have also been given as host plants by some experts.  Furcula borealis does not appear to be very common in my general area, according to Handfield, who notes a flight period for the adult moth from the beginning of June through mid-August.

I have photographed this species in 2000 on 30 May; in 2002 on 9 and 10 June.