Figs 85–89, 179, 233. Map 18
Mamestra promulsa Morrison, 1875a: 97.
Scotogramma promulsa; Dyar 1903: 159.
Lasiestra promulsa; McDunnough 1938: 72.
Lasionycta promulsa; Lafontaine et al. 1986: 264.
Scotogramma infuscata Smith, 1899: 42, syn. n.
Lasiestra infuscata; McDunnough 1938: 72.
Lasionycta infuscata; Lafontaine et al. 1986: 265.
Type material. Mamestra promulsa: syntypes 2 ♀ [ MSU, examined]. Type locality: Colorado. Scotogramma infuscata: lectotype ♀ [ USNM, examined]. Type locality: Gibson Mountains, Colorado. Th e lectotype female was designated by Todd (1982: 108).
Diagnosis. The forewing of this widely distributed species is uniform gray brown to yellow brown. Th e lines are variable, usually fairly inconspicuous, and the spots are faint. Th e orbicular spot is most often oval, rarely round, and lacks an ocellus. The ventral hindwing is gray brown with an indistinct marginal band and a small illdefined discal spot. Th e genitalia of both sexes are typical for the sub-group. Lasionycta promulsa is distinguished from the few brown species in the L. leucocycla and L. phoca sub-groups by the ventral hindwing. Th e discal spot is larger and the postmedial line and band are darker and better defined in these two. In addition, the male antenna of L. promulsa is slightly wider than in the L. phoca sub-group (> 2.1× central shaft in L. promulsa, usually <2× shaft in the L. phoca sub-group). Lasionycta promulsa occurs with L. pulverea, sp. n. in Alberta and L. silacea in the Pacific Northwest. Differences between them are described under these species.
The seven CO1 haplotypes of this species are tightly clustered and differ by up to 0.7 % ( Fig. 248).
Distribution and biology. Lasionycta promulsa occurs from Rampart House in northern Yukon to southwestern British Columbia in the west and southern New Mexico in the Rocky Mountains. It is most common near timberline and is nocturnal. The northern Yukon populations are found in sage grassland, although those on Montana Mountain in southwest Yukon occur in rocky alpine tundra like other populations to the south. Lasionycta promulsa flies from mid-July through August.
Geographical variation. The ground color and forewing lines vary between regions. Lasionycta promulsa is mostly dull gray brown without contrasting markings. Colorado material is mostly warmer yellow brown and the transverse lines are dark. The Uinta Mountain population in northeastern Utah is an unmarked orange brown, while that from the Wasatch Range in central Utah is pale chalky gray with darker lines.
Remarks. Th is species was known as L. infuscata for many years.