Semiaquatic bugs (Hemiptera, Heteroptera, Gerromorpha) are predatory insects currently represented in Brazil by five families, 38 genera, and 250 species. Studies in the northern portion of the country are concentrated between the two largest cities in the region, Manaus and Belém, resulting in knowledge gaps. Based on material recently collected in the states of Acre and Amazonas, we present here the description of five new species: Rheumatobates acreanus Rodrigues and Moreira, sp. nov., R. apurina Rodrigues and Moreira, sp. nov., R. bicolor Rodrigues and Moreira, sp. nov., R. chicomendesi Rodrigues and Moreira, sp. nov., and Tachygerris septentrionalis Rodrigues and Moreira, sp. nov., Additionally, we detected synonymy between Euvelia discala Polhemus and Polhemus, 1984 (senior) and E. meta Molano, Moreira and Morales, 2016 (junior), and between R. bonariensis (Berg, 1898) (senior) and R. minimus Drake, 1958 (junior). Furthermore, we provide figures of the type specimens of R. bonariensis, R. klagei Schroeder, 1931, R. minimus, and R. wrighti Drake and Harris, 1937. Finally, new records from northern Brazil are provided for 29 species of semiaquatic bugs, of which four are first recorded from Brazil (Metrobates fugientis Drake and Harris, 1945, Telmatometra indentata Kenaga, 1941, Trepobatoides boliviensis Hungerford and Matsuda, 1958 and Hydrometra williamsi Hungerford and Evans, 1934), 26 from Acre, and three from Amazonas. Our study increases to 258 the number of gerromorphan species recorded from Brazil, to 29 those known from Acre, and to 92 those from Amazonas.
Rodrigues et al. (Tue,) studied this question.