Lasionycta illima

Description. Head – Antenna of male bipectinate; individual segments 2.5× as wide as central shaft. Antenna of female filiform and ciliate. Dorsal antennal segments dark gray proximally, white distally. Scape white. Eye size moderately reduced, ellipsoid. Palpus pale luteous white with scattered dark-gray scales. Frons covered in nearly equal numbers of dark-gray and white hair-like scales. Top of head slightly darker than frons. Thorax – Vestiture a mixture of white and gray hair-like scales and bifurcate white-tipped gray scales, appearing light gray ventrally and gray with slightly darker bands on prothoracic collar and patagium dorsally. Legs covered with a mixture of dark-gray and pale-luteous white scales. Tarsal segments dark gray, ringed distally with white. Wings – Forewing length: male 12 mm (expanse 27 mm); female 12–13 mm (expanse 26–28 mm). Forewing with nearly equal mixture of gray, black, and white, and fewer orange-yellow scales, appearing uneven, slightly bluish gray with patches of warm ochre gray, lightest beyond postmedial line. Basal line and antemedial line double, dark gray filled with pale gray, jagged. Medial line dark gray, strongest at costa and in fold. Postmedial line strongly scalloped between veins, gently excurved from costa to bottom of cell, then oblique to posterior margin. Subterminal line pale, uneven, preceded by nearly solid dark-gray shade. Spots dark gray. Orbicular spot nearly round, filled with pale-gray scales peripherally and a dark-gray central ocellus. Reniform spot less prominent than orbicular spot, weakly hourglass shaped, filled with slightly paler gray scales peripherally and dark-gray scales centrally. Claviform spot small, dark gray, filled with ground color. Fringe weakly scalloped light and dark gray. Ventral forewing whitish gray with slight dark-gray suffusion along costa and cubital veins. Markings similar dark gray. Discal spot large. Postmedial line complete. Marginal band sharply demarcated medially. Fringe more distinctly checkered than on dorsum. Dorsal hindwing ground color luteous white, with large dark-gray discal spot, scalloped postmedial line, and solid sharply demarcated dark-gray marginal band. Hindwing fringe medium gray proximally, nearly white distally. Ventral hindwing luteous off-white with scattered dark-gray scales. Markings all a similar dark gray. Basal dash present in most specimens. Discal spot large, similar in size and color to ventral forewing discal spot. Postmedial line complete, undulating, located near marginal band and parallel to its medial margin. Marginal band relatively thin with sharply demarcated medial margin. Fringe light gray proximally and white distally, faintly checkered. Abdomen – Similar to dorsal hindwing, covered with pale luteous-white and scattered dark-gray scales. Male genitalia – (Fig. 153). Genital capsule and aedeagus as described in the L. leucocycla species-group and L. leucocycla sub-group descriptions. Valve approximately 6.8× as long as wide, with weak neck at base of cucullus. Cucullus slightly rounded, with corona comprised of single row of setae. Vesica with 2 basal cornuti (N = 1). Female genitalia – Ovipositor, segment VIII, and bursa copulatrix as in L. leucocycla species-group description. Corpus bursae approximately 1.1× ductus bursae length and 0.7× as wide as long.

Distribution and biology. Lasionycta illima occurs from Pink Mountain in northeastern British Columbia through southern Yukon to eastern Alaska. Records suggest that it is predominantly nocturnal. It is very rare in collections.