Phyllophaga delphinicauda, new species (Coleoptera: Scarabaeidae, Melolonthinae), is described from the eastern Sierra de Bahoruco in the Dominican Republic. Supportive taxonomic and biogeographic information is presented in a discussion of the new species' apparent relationship to Phyllophaga davidsoni Woodruff, 2004, and Phyllophaga carnegie Woodruff, 2004. The potential geographic and temporal distributions of P. delphinicauda are examined and its status as a species of conservation concern is discussed. A modification to the existing key to the Phyllophaga of Hispaniola (Woodruff 2004) is presented to accommodate this new species.