Phenotypic characters are traditionally the main information for species discrimination in taxonomic studies of invertebrates. However, the presence of inter- and intraspecific polymorphism makes it difficult to identify species in many groups such as Neotropical social wasps. Herein, we examined different sources of biological information such as adult morphology, male genitalia, nest architecture, and genetic data applying an integrative taxonomic approach to study pinned museum specimens belonging to the social wasp genus Pseudopolybia de Saussure, 1863. Based on multiple independent lines of evidence, we described a new Neotropical swarm-founding social wasp, Pseudopolybia cryptica sp. n. Moreover, we proposed a phylogenetic hypothesis for Pseudopolybia including this new species. Our taxonomic findings applying an integrative approach reinforce that the social wasp diversity in the Neotropics may be underestimated due to morphological similarity.