N.B.: considered a senior synonym of Utopiellum Strand, 1901b: 31 [urn:lsid:nmbe.ch:spidergen:05241] (type Erigone mirabilis L. Koch, 1879 = Hilaira herniosa (Thorell, 1875)) by Holm, 1945b: 28 and of Soudinus Crosby & Bishop, 1936b: 59 [urn:lsid:nmbe.ch:spidergen:05240] (type Gongylidium canaliculatum Emerton, 1915) by Marusik et al., 1993a: 68; not a junior synonym of Leptothrix Menge, 1869 (Merrett, Locket & Millidge, 1985: 397, contra Millidge, 1977); not a senior synonym of Oreoneta Chyzer & Kulczyński, 1894 (Saaristo & Marusik, 2004a: 208, not accepted by Breitling, 2021: 21); not a senior synonym of Arctilaira Chamberlin, 1921 (Tanasevitch & Marusik, 2026: 119, contra Holm, 1960b: 119).

Transferred to other genera:

Hilaira algida Hackman, 1954 -- see Sougambus

Hilaira alpina Eskov, 1987 -- see Oreoneta

Hilaira balia Crosby & Bishop, 1929 -- see Neomaso

Hilaira banini Marusik & Tanasevitch, 2003 -- see Arctilaira

Hilaira bellans (Chamberlin, 1921) -- see Arctilaira

Hilaira carli Lessert, 1907 -- see Sciastes

Hilaira corneliae (Chamberlin & Ivie, 1944) -- see Disembolus

Hilaira cryophila (Koelbel, 1886) -- see Oreoneta

Hilaira curvitarsus (Sørensen, 1898) -- see Arctilaira

Hilaira dubia Hackman, 1954 -- see Sciastes

Hilaira faeroica Schenkel, 1925 -- see Oreoneta

Hilaira frigida (Thorell, 1872) -- see Oreoneta

Hilaira frigida brunnea (Emerton, 1882) -- see Oreoneta

Hilaira frigida intercepta (O. Pickard-Cambridge, 1873) -- see Oreoneta

Hilaira gertschi Holm, 1960 -- see Arctilaira

Hilaira glacialis (Thorell, 1871) -- see Arctilaira

Hilaira holmi Eskov, 1981 -- see Drepanotylus

Hilaira jamalensis Eskov, 1981 -- see Arctilaira

Hilaira leviceps (L. Koch, 1879) -- see Oreoneta

Hilaira mentasta (Chamberlin & Ivie, 1947) -- see Sciastes

Hilaira modesta (Thorell, 1872) -- see Oreoneta

Hilaira mongolica Wunderlich, 1995 -- see Oreoneta

Hilaira montigena (L. Koch, 1872) -- see Oreoneta

Hilaira montigena arctica Holm, 1960 -- see Oreoneta

Hilaira nivalis Holm, 1937 -- see Arctilaira

Hilaira plagiata Tullgren, 1901 -- see Laminacauda

Hilaira punctata Tullgren, 1955 -- see Oreoneta

Hilaira ruderalis (Sørensen, 1898) -- see Arctilaira

Hilaira sinuosa Tullgren, 1955 -- see Oreoneta

Hilaira tatrica Kulczyński, 1915 -- see Oreoneta

Hilaira tatrica garrina Chamberlin, 1949 -- see Oreoneta

Hilaira uncata (O. Pickard-Cambridge, 1873) -- see Drepanotylus

Hilaira vexatrix (O. Pickard-Cambridge, 1877) -- see Arctilaira

Hilaira whymperi Jackson, 1933 -- see Arctilaira

In synonymy:

Hilaira aquilonia (Hackman, 1954, T from Sciastes) = Hilaira canaliculata (Emerton, 1915) (Aitchison-Benell & Dondale, 1990: 224, sub Soudinus)

Hilaira curvitarsis (Emerton, 1917) = Hilaira herniosa (Thorell, 1875) (Bishop & Crosby, 1935c: 236, sub Utopiellum mirabile)

Hilaira glacialis thienemanni Schenkel, 1939 = Hilaira pervicax Hull, 1908 (Holm, 1945b: 29)

Hilaira mirabilis (L. Koch, 1879, T from Utopiellum) = Hilaira herniosa (Thorell, 1875) (Holm, 1945b: 28)

Hilaira monedula Saito, 1986 = Hilaira herniosa (Thorell, 1875) (Eskov, 1987a: 1030)

Hilaira ryabukhini Eskov & Marusik, 1991 = Hilaira canaliculata (Emerton, 1915) (Marusik et al., 1993a: 68)

Hilaira zaicewi Kulczyński, 1916 = Hilaira proletaria (L. Koch, 1879) (Holm, 1973: 85)

Nomen dubium:

Hilaira consimilis (O. Pickard-Cambridge, 1875b: 192, pl. 27, f. 2, m, Europe, originally in Erigone) -- Holm, 1945b: 28