Lasionycta quadrilunata

Lasionycta quadrilunata (Grote)

Figs 54–56, 166, 167, 222, 223. Map 14

Anarta quadrilunata Grote, 1874b: 244

Lasiestra quadrilunata; McDunnough 1938: 71.

Lasionycta quadrilunata; Lafontaine et al. 1986: 263.

Lasionycta quadrilunata yukona Lafontaine, 1986: 264.

Type material. Anarta quadrilunata: holotype ♀ [USNM, examined]. Type locality: Colorado Territory. Lasionycta quadrilunata yukona: holotype ♀ [CNC, examined]. Type locality: 17 km WNW Burwash Flats, Yukon.

Diagnosis. Lasionycta quadrilunata is an alpine species characterized by a large hindwing discal spot, a short broad digitus resembling an obtuse triangle, and a small rounded cucullus bearing a corona of four rows of setae. Th e forewing is light gray or slate gray with a yellow or olive tint. Th e dark-gray transverse lines are prominent but the spots are indistinct. Th e female bursa is similar to that of L. staudingeri but L. quadrilunata has an increased number of short setae on abdominal segment VIII, similar to L. lagganata.

The male antenna of quadrilunata is weakly biserrate, almost beadlike (1.4× the width of the central shaft).

Distribution and biology. Records of L. quadrilunata form an arc on a map, from south-central Alaska down the spine of the Rocky Mountains to Colorado. It flies over scree tundra and is diurnal. The flight period is from mid-July to early August.

Geographical variation. The populations of L. quadrilunata are arranged in two subspecies.