Abstract

The small subfamily Masoninae van Achterberg, 1995 (Hymenoptera, Braconidae) comprises nine species across two genera: Anoblepsis Engel & Bennett, 2008, and Masona van Achterberg, 1995. The genus Masona is notable for its rarity in collections and distinctive morphology, with females being apterous, having a prognathous head, and strongly swollen femora. In this study, we describe Masona uau Santos & Dal Pos sp. n. from Brazil, representing the second species and specimen recorded in the country and the first for the state of Tocantins. Additionally, we provide the most comprehensive morphological documentation of one species of the genus to date, incorporating low-vacuum SEM images, automontage photographs, and detailed drawings, enhancing the understanding of its diagnostic features and facilitating future identifications.