Larval morphology of the monotypic rygmodine genera Anticura Spangler, 1979 from Chile and Cylomissus Broun, 1903 from New Zealand is described, based on field-collected larvae associated with adults and authenticated by CO1 and 18S DNA sequences. General morphology and chaetotaxy of the head capsule is described and illustrated for all three instars of Anticura flinti Spangler, 1979 and the first and third instar of Cylomissus glabratus Broun, 1903. Both genera are similar in larval morphology, sharing several unique larval characters (e.g., bidentate nasale in the first instar, presence of numerous additional setae on parietale in the first instar), which support their close phylogenetic relationship and provides morphological support for the transfer of Anticura to the Rygmodinae. The presence of numerous additional setae on the parietale of all instars and characteristic chaetotaxy of the maxillary stipes are hypothesized as potential larval synapomorphies of the subfamily Rygmodinae. Field observations show that larvae and adults of both genera are aquatic, most frequently collected from moss in the splash zone at the sides of stony streams and small rivers.