ACTA ENTOMOLOGICA MUSEI NATIONALIS PRAGAE Published 30.iv.2014 Volume 54(1), pp. 65–98 ISSN 0374-1036 http://zoobank.org/urn:lsid:zoobank.org:pub:0C538D2D-9EC9-4F08-BCF3-59296858F53F Taxonomic revision of the Neotropical genus Oiovelia (Hemiptera: Heteroptera: Veliidae) Higor D. D. RODRIGUES 1,2) , Alan Lane De MELO 3) & Ruth L. FERREIRA-KEPPLER 1) 1) Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, 69011-970, Manaus, AM, Brazil; e-mails: higorddr@gmail.com; ruth@inpa.gov.br 2) Current address, Museu de Zoologia, Universidade de São Paulo, 04263-000, São Paulo, SP, Brazil 3) Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 30123-970, Belo Horizonte, MG, Brazil; e-mail: aldemelo@icb.ufmg.br Abstract. The genus Oiovelia Drake & Maldonado-Capriles, 1952 includes foam-inhabiting insects that occur from Venezuela to Argentina and contains four previously described species: Oiovelia brasiliensis Moreira, Nessimian & Rúdio, 2010, O. cunucunumana Drake & Maldonado-Capriles, 1952, O. rivicola Spangler, 1986, and O. spumicola Spangler, 1986. A redescription of the genus, diagnostic information on the four described species, description of four new species from Brazil (O. chenae sp. nov., O. hamadae sp. nov., O. pydanieli sp. nov., and O. viannai sp. nov.), an identiÝcation key, photos, and illustrations of male genitalia of all the species are herein presented. To facilitate separation of the New World genera of the subfamily Veliinae, an updated identiÝcation key is also presented. Key words. Heteroptera, Gerromorpha, Veliidae, aquatic insects, foam, identiÝ- cation key, new species, Brazil, South America, Neotropical Region Introduction The water striders of the genus Oiovelia Drake & Maldonado-Capriles, 1952 (Veliidae: Velii- nae) are semi-aquatic insects, living predominantly on foam formed on the surface of black water streams, occasionally being collected on tree trunks, kinon [= allochthonous organic material, as Þowers, fruits and wood, drifting on the water surface and accumulated in the stream banks (FITTKAU 1977)], or more rarely attracted to light traps (SPANGLER 1986, MOREIRA et al. 2010). At present, representatives of the genus Aphrovelia Polhemus & Polhemus, 1988, restricted to Madagascar, and Pseudovelia gnoma Polhemus, 1979, recorded from Sri Lanka, in addition to Oiovelia, are the only semi-aquatic Heteroptera collected on foam (ANDERSEN 1983, POLHEMUS