Background
Water bugs in general play an important role in freshwater ecosystems, and knowledge about them is essential for the study of water biology and the proper management of aquatic habitats. The Neotropical fauna is relatively well known, but the existence of large under-collected areas makes taxonomic and faunistic studies concerning the aquatic and semiaquatic bugs from tropical America urgent. New information: Distributional information is presented for thirty-eight species of Gerromorpha and five Nepomorpha, including first records from the Brazilian states of Bahia (Mesoveliaamoena), Ceará (Limnogonusprofugus and Rhagoveliawhitei), Espírito Santo (R.lucida), Goiás (Halobatopsisplatensis and R.zela), Mato Grosso (Rheumatobatesbonariensis), Pará (Nerthraterrestris), Paraná (H.spiniventris, Hydrometrafruhstorferi and R.janeira), Piauí (Microveliaayacuchana, M.pulchella, Neogerrislubricus and Platyveliabrachialis), Rio de Janeiro (Martaregabentoi) and São Paulo (Rheumatobatesminutusflavidus); and the Peruvian region of Madre de Dios (Rhagoveliafontanalis).