Harrahium Witenberg, 1926

Dronen, Norman O. & Blend, Charles K., 2015, Updated keys to the genera in the subfamilies of Cyclocoelidae Stossich, 1902, including a reconsideration of species assignments, species keys and the proposal of a new genus in Szidatitreminae Dronen, 2007, Zootaxa 4053 (1), pp. 1-100 : 40

Key to the species of Harrahium Witenberg, 1926

1a. Rudimentary oral sucker absent; eggs relatively small, 125 µm x 65 µm..................... H. tringae ( Brandes, 1892)

1b. Rudimentary oral sucker present; eggs relatively large, 161 µm x 91 µm....................... H. halli ( Harrah, 1922)