Gerromorpha or semiaquatic bugs have the ability to walk on the surface of the water and occupy a wide variety of habitats. They are relatively well studied in the Neotropical Region, but some species are known only from the type localities or have many gaps in their documented distributions. In this study we examined specimens housed in the National Museum of Natural History, Smithsonian Institution, and report new records for 17 species: Mesovelia bila, Hydrometra argentina, H. caraiba, H. comata, Limnobatodes paradoxus, Euvelia lata, E. mazzucconiae, Husseyella turmalis, Oiovelia cunucunumana, Paravelia conata, Platyvelia brachialis, Steinovelia virgata, Halobatopsis platensis, H. spiniventris, Ovatametra obesa, Limnogonus aduncus aduncus, and L. recurvus.