Leptostylopsis grandis Vlasak and Androw, new species, is described from Puerto Rico. A brief history of the revisional studies on the Caribbean members of the genus is presented. Morphological characters separating the new species from the closely related species Leptostylopsis argentatus (Jacquelin du Val) are discussed, and a modification to the key to the species of Leptostylopsis Dillon occurring in Puerto Rico is presented.