The alpinus species group

Diagnosis. Larvae of the Oreodytes alpinus species-group can readily be distinguished from those of both the alaskanus and septentrionalis species-groups by the following combination of characters: size smaller: HL <0.65 mm, 0.87 mm, 1.22 mm and FRL <0.50 mm, 0.68 mm, 0.95 mm (instar I, II, III, respectively); each tarsus with at least one dorsal secondary seta (instars II and III).