Lasionycta perplexa

The three species in the L. perplexa sub-group are moderately sized with mottled gray to blue-gray forewings with dentate lines and distinct spots, including the claviform spot. The hindwings are nearly uniform gray on both surfaces, with markings limited to the darker discal spot and postmedial line. Males are easily sorted by antennal structure – either biserrate or bipectinate – and locality. Females are difficult to identify and are best identified by association with males. The three species resemble L. subfuscula, although males are easily differentiated by their narrower antennae (over 4× width of the shaft in L. subfuscula). Females can be told from those of L. subfuscula by the nearly straight orientation of the corpus bursae to the ductus bursae (angled 30° in L. subfuscula).

The male genitalia are similar to those of the L. leucocycla sub-group, with a weak constriction below the moderate-size cucullus bearing a corona of a single row. The costal lobe of the sacculus is variable, extending to or above the valve margin. The vesica shape is typical for the species-group and the basal part bears 0–3 cornuti.

The female genitalia are also similar to those of the L. leucocycla sub-group. The corpus bursae is ovoid with a slightly pointed anterior end. Th e corpus bursae is straight or only slightly angled toward the left from to the ductus bursae. Females of the three species cannot be differentiated structurally.