New World genus Epiphlaeus is redefined and evolutionarily linked to its sister genus Opitzius Barr. Epiphlaeus includes six species as follows: E. adonis sp. nov., E. duodecimmaculatus (Klug), E. fundurufus sp. nov., E. princeps (Gorham), E. pulcherrimus (Gorham), E. quattuordecimmaculatus Chevrolat, and E. tigrinus sp. nov. The monotypic Opitzius is based on O. thoracicus Barr. Specimens of these two genera are variously deposited in 37 institutional and private collections. These checkered beetles frequent the surface of felled tree boles to forage on adults and immatures of lignicolous insects. Their large size and mobility make them very noticeable on the bark of fallen trees. It is postulated that they are participants in a mimetic ring with log-inhabiting mutillids and flies part of the mimetic mix. Hennigian principles were applied to 22 adult morphological characters, which yielded a nearly totally resolved phylogenetic hypothesis between Epiphlaeus and Opitzius, and among Epiphlaeus species groups. The combined geographical range of the inclusive species extends from northwestern Nicaragua to southeastern Brazil. It is hypothesized that ancestral Epiphlaeus —Opitzius evolved in South America with some descendants entering Insular Central America after closure of the Panamanian portals during the Miocene. Pleistocene climatic factors are thought to have influenced species diversity, and perhaps speciation events in conjunction with aspects of dispersal, vicariance, and taxon pulse dynamics.