Generic diagnoses to all stages of the genus Paraphaenocladius Thienemann, 1924 are given. A synapomorphic diagram showing Paraphaenocladius as the sistergroup of Parametriocnemus is presented. In addition a parsimony analysis using the PAUP program is given. The genus is divided into 5 species groups, the irritus, dewulfi, proprius, penerasus, and impensus groups. The irritus and dewulfi groups combined apparently fonn the sister group of the proprius, penerasus and impensus groups combined, with the proprius group forming the sister group of the penerasus and the impensus groups combined. Keys to male and female imagines, pupae and larvae are given.
Twenty-three taxa including 16 species and 7 subspecies are described or redescribed. P. irritus longiocoslatus subsp. n. is described as male imago; P. pseudirritus nearcticus subsp. n. as male imago, pupa and larva; P. pseudirritus maurus subsp. n., P. crassicaudatus sp. n., P. tonsuratus sp.n., and P. triangulus sp. n. as male imagines; P. pusillus sp. n. as male imago, pupa and larva; P. innasus sp. n. as male imago and pupa; P. impensus contractus subsp.n. as male and female imago; and P. exagitans longipes subsp. n. as male imago. P. albusalatus Chaudhuri & Sinharay is regarded as a subspecies of P. impensus (Walker) and P. monticola Strenzke as a subspecies of P. exagitans (Johannsen). P. cuneatus (Edwards) known from female imago only is regarded as a valid species. P. discretus (Johannsen) comb. n. is a nomen dubium and a probable synonym of P. impensus. P. triquetrius Chaudhuri & Bhattacharyay is transferred to Parametriocnemus Goetghebuer.
The genus is nearly exclusively holarctic with only the dewulfi group Afrotropical with P. dewulfi (Goetghebuer) also occurring in Saudi Arabia, P. proprius Chaudhuri & Sinharay and P. impensus albusalatus occurring in India and possibly Indonesia, and P. exagitans longipes Neotropical. The differention into subspecies and some species appears to have taken place as a result of postglacial and interglacial vicariance events.