The small species of Belostoma (Heteroptera: Belostomatidae): revision of plebejum group

Nieser gathered the water bug species included by Lauck in the groups Belostoma pygmeum and Belostoma plebejum in a single group, Belostoma plebejum. We follow this criterion and use the terminology used by EstCvez and Polhemus for species descriptions. The Belostoma plebejum group includes seven small species with the ventral diverticulum of male genitalia recurved ventrad: Belostoma lariversi De Carlo, 1969; B. micantulum (Stål, 1858); B. plebejum (Stål, 1858); B. pygmeum (Dufour, 1863); B. minusculum (Uhler, 1884). B. parvum sp. nov. from Venezuela, Colombia, Guyana, Suriname and Brazil, and B. nicaeum sp. nov. from Manaus, Brazil. The two new species are described and illustrated, and new synonymies are proposed.