Hydrachnidae
Hydrachna approximata Halik, 1940
Hydrachna australica Lundblad, 1941
Hydrachna baculoscutata Crowell, 1960
Hydrachna bilobata Halik, 1940
Hydrachna bivirgulata Piersig, 1897
Hydrachna canadensis Marshall, 1929
Hydrachna comosa Koenike, 1896
Hydrachna conjecta Koenike, 1895
Hydrachna conjectoides Lundblad, 1947
Hydrachna crenulata Marshall, 1930
Hydrachna cruenta Müller, 1776
Hydrachna evansensis Stout, 1953
Hydrachna geographica Müller
Hydrachna globosa (De Geer, 1778)
Hydrachna goldfeldi Thor, 1916
Hydrachna hamata Lundblad, 1947
Hydrachna hesperia Lundblad, 1934
Hydrachna hungerfordi Lundblad, 1934
Hydrachna hutchinsoni Lundblad, 1934
Hydrachna laceriscuta Lundblad, 1941
Hydrachna leegei Koenike
Hydrachna linderi Lundblad, 1947
Hydrachna magniscutata Marshall, 1927
Hydrachna maramauensis Stout, 1953
Hydrachna marshallae Lundblad, 1934
Hydrachna microscutata Marshall, 1929
Hydrachna miliaria Berlese, 1888
Hydrachna mystomirabilis Habeed, 1954
Hydrachna odontognatha Canestrini, 1884
Hydrachna palustris Smit, 1992
Hydrachna processifera Koenike, 1903
Hydrachna rotunda Marshall, 1930
Hydrachna simulans Marshall, 1928
Hydrachna skorikowi Piersig, 1900
Hydrachna stipata Lundbald, 1934
Hydrachna tasmanica Lundblad, 1947
Hydrachna triscutata Lundblad, 1947
Hydrachna uniscutata Thor, 1897
Hydrachna wainuiensis Stout, 1953
