Hydrachnidia Krantz, 1978 - water mites Superfamily Arrenuroidea Thor, 1900 Family Momoniidae Viets, 1926 1 Subfamily Momoniinae Viets, 1926 2 Subfamily Cyclomomoniinae Smith, 1989 [monotypic] 3 Subfamily Momonidinae Lundblad, 1941 [monotypic] 4 Subfamily Stygomomoniinae Motaş & Tanasachi, 1946