Neoculex was originally proposed as a distinct genus by Dyar (1905), with Culex territans Walker, 1856 as its type species. It was regarded as a synonym of Culex by Brunetti (1914) and treated as a subgenus of Culex by Dyar (1918). In his comprehensive treatment of Culex, Edwards (1932) included Maillotia Theobald, 1907, Eumelanomyia Theobald, 1909 and Protomelanoconion Theobald, 1909 as synonyms of Neoculex and divided the subgenus into three groups: Group A (Neoculex or apicalis-group), Group B (Eumelanomyia or albiventris-group) and Group C (Protomelanoconion or uniformis-group). In his later work on the Afrotropical Culicinae, Edwards (1941) retained the albiventris and uniformis groups and split Group A into three groups, the apicalis, pulchrithorax and rima groups. King & Hoogstraal (1947) followed this scheme and recognised a sixth group, Group F, for pedicellus King & Hoogstraal, 1947 and crassistylus Brug, 1934 from New Guinea. As indicated by Mattingly & Marks (1955) and Belkin (1962), the groups recognised by Edwards (1932, 1941) and King & Hoogstraal (1947) give little idea of natural relationships because they are based on superficial characters that greatly overlap with characters exhibited by members of other subgenera of Culex. This is obvious from his treatment of Mochthogenes as a subgenus separated from the Protomelanoconion (i.e. uniformis group) of Neoculex based on the relative length of the male palpi. As pointed out by Bram (1969), these groups are so similar in the larval stage that they should be included in the same subgenus. With this as background, Sirivanakarn (1971) proposed a reclassification of Neoculex based principally on structural differences observed in the genitalia of males. Sirivanakarn removed Eumelanomyia and Maillotia from synonymy with Neoculex, established them as separate subgenera of Culex, and synonymised Mochthogenes with Eumelanomyia. The restricted concept of Neoculex that resulted from these actions, including the recognition of three subordinate species groups, still stands today.