Macrostomus amazonensis species-group

Macrostomus falcatus sp. nov. belongs in the M. amazonensis species-group as described by Rafael & Cumming (2015) with the following characters: 1 pair of proclinate ocellar setae; no postsutural supra-alar seta; wing mainly hyaline with apical margin brown infuscate; tergite 8 short, not projected posteriorly; epandrium without anterodorsal cleft; cercal bridge small; posterior cercus elongate, simple, upwardly directed; ejaculatory apodeme with very short dorsal lamella.