A new genus and species of Reduviidae, Tribelocodia ashei gen.n., sp.n, are described from French Guyana. The relationships of Tribelocodia are analyzed within the context of a morphology-based cladistic analysis of Reduviidae. The new genus is placed within the clade Ectrichodiinae+Tribelocephalinae and shows a bizarre combination of characters thought synapomorphic for either Ectrichodiinae or Tribelocephalinae. The analyses support Tribelocodia as the sister taxon to the enigmatic African Xenocaucini within Tribelocephalinae. Tribelocodia ashei, therefore, represents the first Neotropical species of this otherwise Paleotropical group. Implications for character evolution of Ectrichodiinae and Tribelocephalinae are discussed and the diagnosis of Tribelocephalinae is revised. Scanning electron and digital micrographs are provided for Tribelocodia ashei. The holotype of Xenocaucus mancinii China and Usinger, 1949 (Xenocaucini) and a specimen of Ectrichodiella minima (Valdes, 1910), which may represent the sister taxon to the remaining Ectrichodiinae, are illustrated using digital photography.