Syngrapha diasema Boisduval 1829

Rarely collected in Alberta, but in secure habitat.

The Alberta records are all of adults collected in the latter half of July.

Holoarctic. Northern Fennoscandia to Siberia, across Arctic and subarctic. In North America, it has been collected across the arctic and subarctic from Labrador to Central Alaska. It has also been collected on 3 occasions in the subalpine in the Nordegg - Cadomin area of Alberta. These are the only records south of the subarctic.

A medium-size moth (3.0-3.3 cm wingspan). The forewings are dark grey or grey-brown with the lower half of the median area blackish. There is a thin U-shaped silver stigma with a short projection outward from the bottom of the U. Hindwings are pale buff or yellow-brown with a broad dark terminal band. Very similar to S. borea and S. orophila, but those species have yellow instead of buff or yellow-brown hindwings. There is also often a faint median line in diasema, lacking in similar species. The antennae are simple and both the sexes are similar.

Alpine and subalpine shrub meadows.

Adults are nocturnal and come to light. There is a single brood per year.

No Alberta data; elsewhere, Dwarf birch (Betula nana).