The Chestnut-bellied Flowerpiercer (D. gloriosissima) belongs to the tanager family Thraupidae, within the diverse subfamily Diglossinae, which consists of 64 species mostly found at high elevations (Burns et al. 2014). There are 14 genera in this subfamily, including the Chestnut-bellied Flowerpiercer's genus, Diglossa, which includes 18 species (Burns et al. 2014). DNA analysis strongly supported Catamenia as sister to the genus Diglossa (Burns et al. 2014). Vuilleumier (1969) subdivided this genus into four species-groups based on physical characteristics, and members of these groups also share habitat preference, social behavior, and feeding behavior (Isler and Isler 1987). The Chestnut-bellied Flowerpiercer belongs to the lafresnayii species-group which also includes D. lafresnayii, D. mystacalis, D. gloriosa, D. humeralis, D. brunneiventris, D. carbonaria, and D. duidae (Vuilleumier 1969). Members of this group are aggressive towards other species and members of the same species (Isler and Isler 1987). Within the lafresnayii species-group, Vuilleumier (1969) recognized two superspecies groups, the lafresnayii superspecies group and the carbonaria superspecies group. Diglossa gloriossisima belongs to the lafresnayii superspecies group, along with D. lafresnayii and D. mystacalis. D. mystacilis, and D. gloriosissima have also been considered subspecies of D. lafresnayii by some authorities (e.g., Storer 1970). Four remaining members of the lafresnayii species-group belong to the carbonaria superspecies group: D. gloriosa, D. humeralis, D. brunneiventris, and D. carbonaria. D. duidae was not assigned to a superspecies group by Vuilleumier (1969). Two genetic studies have investigated relationships among flowerpiercers and included samples of D. gloriosissima. Mauck and Burns (2009) sampled mtDNA data from all species of flowerpiercers. Burns et al. (2014) also sampled all species and included mtDNA data as well as some nuclear sequences from some species. Both studies agree with respect to the relationship of D. gloriosissima to other flowerpiercers. In both studies, D. gloriosissima is the sister species to D. lafresnayii. D. mystacalis is the sister taxon to the clade containing D. gloriosissima and D. lafresnayii. Thus, the monophyly of Vuilleumier’s (1969) lafresnayii superspecies is confirmed with genetic data. However, the members of the carbonaria superspecies are not closely related to the lafresnayii superspecies or to D. duidae. Thus, Vuilleumier’s (1969) lafresnayii species-group is not monophyletic and should not be recognized.