Subgenus Boreosimulium Rubtsov & Yankovsky

Boreosimulium Rubtsov & Yankovsky 1982: 183-184 (as genus).

Type species: Melusina annulus Lundstrom 1911: 17-18, by original designation.

Diagnosis (Modified from Adler et al., 2004).

Adults: Radius with hair dorsobasally, scutum typically unpatterned. Female: claws each with basal thumb­like lobe. Cibarium with or without oblique rows of denticles. Spermatheca unpigmented proximally, wall with polygonal pattern. Male: Gonostylus slender, tapered to pointed apex, with 1 apical spinule. Ventral plate with median keel typically weak or well developed. Paramere with 0, 1 or multiple apical spines.

Pupa: Gill with 4 filaments. Cocoon slipper shaped.

Larva: Antenna with 3 or more hyaline bands or spots. Abdominal segments IX with or without prominent ventral tubercles. Abdominal setae unbranched, translucent, sparse. Rectal papillae of 3 compound lobes.