The nymphalid tribe Preponini (Lepidoptera) contains some of the most highly visible and easily recognized Neotropical butterflies, yet work is still needed to clarify certain areas of its taxonomy and improve our understanding of its evolution. We expanded the existing molecular sequence data set by doubling the number of genes and individuals, and we used Maximum Likelihood and Bayesian Inference to reconstruct the phylogeny. This analysis was complemented with a comparative morphological study of certain taxa, to help resolve generic and species-level taxonomic issues. The phylogeny strongly supported the only species formerly included within Prepona Boisduval, [1936] that has red wing markings as the sister to the clade of colorful, putatively mimetic species formerly placed in the genus Agrias Doubleday, 1844. One species, Prepona pheridamas (Cramer, [1777]), seems sufficiently isolated in terms of both DNA sequence divergence and morphology to merit placement in a new monotypic genus, which we describe as Mesoprepona Bonfantti, Casagrande & Mielke, n. gen. Based on DNA sequence divergence and sympatry with its sister species, we restore Archaeoprepona priene Hewitson, 1859 to species status (stat. rest.). DNA data and a morphological study of the Prepona pylene Hewitson, 1859 complex resulted in the restoration of Prepona eugenes Bates, 1865 and Prepona gnorima Bates, 1865 to species rank (stat. rest.). Broadening the taxonomic representation by including specimens from distant geographic locations, and including greater phenotypic diversity, allowed us to uncover unappreciated taxonomic diversity and provide a firmer basis for exploring the evolution of this group of spectacular butterflies.