A new species of katydid is described from the Lesser Antillean island of St Maarten, Dutch West Indies. Phoebolampta caeruleotergum sp. n. (Tettigoniidae: Phaneropterinae) differs from congeners in having a deeply incised humeral sinus, ventral valvulae of the ovipositor broad, at least half the width of the gonoplac, and male cerci shorter than the subgenital plate, with gently hooked apical lobes of near equal size.