Lasionycta silacea Crabo & Lafontaine 2009

Description. Head – Antenna of male strongly biserrate and fasciculate, 2.2–2.6× as wide as central shaft, individual segments triangular with slightly concave distal side and acute apices. Antenna of female filiform and ciliate. Dorsal antenna segments dark olive gray proximally, slightly lighter olive gray distally. Scape light grayish yellow, tuft at base of dorsal antenna light gray. Eye normal size. Palpus light grayish yellow medially, similar scales mixed with gray scales laterally. Frons light grayish yellow centrally, light gray laterally. Top of head a mixture of entirely pale yellowish-gray hair-like scales and similar scales banded subapically with dark gray and tipped with white, appearing light olive gray. Thorax – Vestiture uniform, same as top of head. Legs with femora covered with olive-gray and yellow scales, tibiae with slate-gray and pale-luteous scales, tarsal segments mostly slate gray ringed distally with pale luteous. Wings – Forewing length: males 14–17 mm (expanse 32–37 mm); females 16–18 mm (expanse 36–38 mm). Forewing ground color a mixture of medium to dark olive-gray, ochre and tan to orange scales, appearing slightly mottled medium to dark olive gray with patches of light to medium grayish ochre. Basal, antemedial, and postmedial lines slightly darker olive gray, ill defined, weakly double with grayish-ochre filling. Basal and antemedial lines irregular. Medial line complete but faint. Postmedial line moderately scalloped between veins, evenly excurved from costa to lower cell then nearly straight to end perpendicular to posterior margin. Subterminal line gray ochre, slightly irregular, preceded by a uniform slightly darker gray-olive shade. Terminal line thin, gray olive. Spots similar color to lines. Orbicular spot round to oval, filled with ground color or slightly lighter scales and an ocellus of same color as spots and lines. Reniform spot kidney shaped, faint, filled with light gray ochre peripherally and same color as lines centrally. Claviform spot absent. Fringe darker gray basally and lighter gray ochre distally, faintly checkered with gray olive between veins. Ventral forewing light olive gray centrally and distal to expected position of the subterminal line, lighter gray ochre in anterior cell, distal to discal spot, and in subterminal area anterior to cubital vein. Discal spot slightly darker, bar like, evident due to lighter scales adjacent to anterior half of spot. Postmedial line similar gray to forewing margin, ill defined, darkest and widest near costa, faint elsewhere. Terminal line thin, evident between veins. Fringe gray ochre, checkered with olive gray between veins. Dorsal hindwing ground color pale gray yellow dusted with dark-gray scales, lighter at costa. Discal spot barely evident, chevron shaped. Postmedial line gray, ill defined, irregular and slightly scalloped in a few specimens. Marginal band fuscous gray, wide with indistinct inner margin, extending proximally almost to postmedial line. Fringe light to medium ochre. Ventral hindwing pale grayish ochre to light gray brown, darker at costa, with dusting of light- to medium-gray scales. Veins slight darker gray, especially distal to postmedial line. Discal spot an ill defined triangle, darker gray than other hindwing markings. Postmedial line light gray, usually inconspicuous and incomplete but occasionally prominent and complete. Marginal band light to medium gray, with ill-defined inner margin. Fringe light to medium ochre. Abdomen – Covered with uniform yellow-gray scales. Male genitalia – (Fig. 181) Genital capsule and aedeagus as in L. leucocycla species-group and L. promulsa sub-group descriptions. Valve approximately 6–7× as long as wide, with costal lobe of sacculus extending above costal valve margin and moderate neck at base of cucullus. Corona single, partially double at apex. Digitus oriented 30° ventral to valve. Vesica with 1–2 (N = 5) slightly angled spike-like basal cornuti placed adjacent to each other on vesica coil. Female genitalia – (Fig. 236) Ovipositor lobe, segment VIII, and bursa copulatrix generally as in L. leucocycla species-group and L. promulsa sub-group descriptions. The corpus bursae relatively large. The distal appendix bursae is relatively slender and pointed.

Distribution and biology. Lasionycta silacea occurs from the British Columbia Coast Range and Washington Cascades to extreme southwestern Alberta. It is common near treeline. Adults are nocturnal and fly from early July through August.