Belladessus Miller and Short, new genus, is described to include two new species of diving beetles, B. femineus Miller and Short, new species (southeastern Venezuela and Suriname) and B. puella Miller and Short, new species (western Venezuela). The genus is placed in the dytiscid tribe Bidessini due to the presence of a distinctive spermathecal spine, among other diagnostic features. The genus is characterized by the absence of an occipital line, presence of basal pronotal striae, presence of a basal elytral stria, absence of a sutural elytral stria, absence of a transverse carina on the elytral epipleuron at the humeral angle, and presence of a distinct marginal bead on the anterior clypeal margin. No male specimens are present among the more than 125 specimens known, and, from this, it is hypothesized that the species are likely parthenogenetic.