A new species of the genus Homeomastax of the subfamily Eumastacinae is described found in the border area between the Andean and Orinoquia regions (Meta and Huila departments) of Colombia. Due to the unique features in the phallic anatomy of the species, it is proposed as a link between the genera Erythromastax and Homeomastax; additionally, the exclusive colour pattern of the species may lead to a new classification of the subfamily.