University of Alberta Museums Search

A small (approximately 2.5 cm wingspan) flimsy moth with a small body and broad wings. Wings light grey., slightly mottled. Basal are red brown, antemedian line prominent, black. Area between antemedian and postmedian lines rust-red, and a small red-brown patch on the costa before the apex. Hindwings light grey. The black antemedian line followed by the wide red median band should separate labradorensis from all but X. packardata McD. These two species are frequently misidentified in collections and elsewhere, and should be dissected for positive identification. In packardata the aedeagus is very slender (about 1/5 as wide as the space within the genital ring (tegument and vinculum) with a peculiar cluster of about 10 setae at the top of the aedeagus that are like cylinders with a thin seta at the tip, like dynamite with a short fuse, and the apex of the valve is flat with a small dorsal process. In labradorensis, the aedeagus is about ½ as wide as the capsule space, there is a large cluster of long tapered cornuti at the top, and the subapical process is larger and projects on the inner surface of the valve as a triangular subapical tooth (D. Lafontaine, pers. comm.).

There is a single annual brood, with adults in Alberta from late May through late August. Adults are nocturnal and come to light. The larvae are polyphagus with a range of mostly herbs but also some woody plants listed as hosts (Covell, 1984).

Xanthorhoe are one of the most difficult groups of geometrid moths to identify, and little has been published on North American members of this genus to date. The illustrated specimen is from Edmonton, and was identified by dissection. Mapped localities are shown as open dots (unverified records) unless the specimen was dissected. Listed by Bowman as X. designata emendata Pears.