This sub-group includes only L. subfuscula, a moderately large gray species with distinct dark lines and spots, including the claviform spot. It resembles members of the L. perplexa sub-group. Males have the widest antenna of any Lasionycta, over 4× as wide as the central shaft, and are easily identified without magnification. Females are the only species in the species-group in which the corpus bursae is angled 30° leftward at its junction with the ductus bursae.

The valve is elongate with a moderate constriction at the base of the cucullus. The costa is angled slightly ventrad beyond the digitus. Th e costal lobe is prominent, extending above the valve margin. Th e cucullus is smaller relative to the valve than in the L. perplexa sub-group, and bears a corona of a singe row of setae. The digitus is angled 30° to the valve axis and is relatively long and slender. Th e female appendix bursae is slightly more slender than those of the L. perplexa sub-group.

CO1 distance analysis suggests that L. subfuscula is a sister group to a large assemblage containing the species of the L. leucocycla and L. perplexa sub-groups, L. staudingeri, and L. subfumosa.