Parapsectrocladius is described in all life history stages as a new genus with type-species Cardiocladius acuminatus Edwards, for four species from Andean South America. The female, pupa and larva of P. acuminatus are described for the first time, from Chile; all stages of P. escondido Cranston & Añón Suárez, sp. n., are described from lentic patagonian Argentina, all stages of Parapsectrocladius reissi sp. n. from a pond in Valdivia, Chile, and P. longistylus sp. n. from males from several locations in south Chile and Argentina and the putatively associated female and pupa from southern Chile. The clade is Patagonian, with larvae occurring in Andean pools, ponds and lakes, including glacial-fed ones, and also in one lowland river in Chiloe. Previous suggested relationships to Cardiocladius Kieffer or Paratrissocladius Zavrel are rejected following phylogenetic analysis, with these placements suggested as due to adult male -based convergent character states. The immature stages, which show resemblance to Psectrocladius Kieffer and Rheocricotopus Thienemann & Harnisch, and the female contribute evidence that Parapsectrocladius forms the sister group to Psectrocladius, which appears monophyletic despite its subgeneric heterogeneity. Immediate next relations to Psectrocladius + Parapsectrocladius are postulated as (Rheocricotopus (both subgenera) + Paracricotopus) then (Nanocladius + Doncricotopus) at next remove.