Euxoa westermanni Staudinger 1857

Euxoa westermanni species-group

The Euxoa westermanni species-group is included in the subgenus Pleonectopoda Grote, one of seven subgenera of Euxoa (Lafontaine 1987). The E. westermanni species-group is the largest of the six species-groups in the subgenus, and includes 20 of the 27 species in the subgenus. It is the only species-group in the subgenus Pleonectopoda Grote that occurs in the Palearctic.

Species in the E. westermanni species-group are best characterized by the male genitalia: the vesica has a subbasal coil (like other species in subgenus Pleonectopoda), the medial diverticulum is closer to the subbasal coil of the vesica than the apex, the subbasal diverticulum is bilobed, and the saccular extensions are short, shorter than the clasper and about ⅓ × as long as the valve.

Most species of the E. westermanni species-group occur in subarctic, alpine, and subalpine habitats and they dominate the Euxoa fauna in these areas. Six species are associated with dunes and open sandy habitats, three in the subarctic (E. hyperborea Lafontaine, 1987, E. churchillensis (McDunnough, 1932), and E. muldersi Lafontaine & Hensel, sp. n.) and three farther south in Canada and northern United States (E. scandens (Riley, 1869), E. quebecensis (Smith, 1900), and E. aurulenta (Smith, 1890)).

One of the species described below is associated with open dunes in northern Canada; the other occurs in alpine areas in western British Columbia.

Descriptions