The genus Liancalus Loew is revised for the Nearctic Region. Seven species are documented from this region including two new species: Liancalusgenualis Loew, Liancalushydrophilus Aldrich, Liancaluslimbatus Van Duzee, Liancaluspterodactyl sp. n., Liancalusquerulus Osten Sacken, Liancalussimilis Aldrich, and Liancalussonorus sp. n. Lectotypes are designated for the following species: Liancalusgenualis, Liancalushydrophilus, Liancalusquerulus, and Liancalussimilis. The species are illustrated, a key to males and females is provided, and their distributions mapped. Adults of Liancalus are some of the largest species of Dolichopodidae and commonly occur on waterfalls and vertical seeps.
Keywords: Dolichopodidae; Hydrophorinae; Nearctic; courtship display; long-legged flies; new species; wings.