A new species of Tithorea, Tithorea pacifica n. sp., is described and diagnosed from pluvial premontane rain-forest in northwestern Ecuador. Two additional new subspecies, T. pacifica euphonia n. ssp. and T. pacifica concordia n. ssp., are also described, from western Colombia and extreme eastern Panama, respectively. Adult specimens and genitalia of both sexes are illustrated for the three known species of Tithorea and the characters that distinguish the species are tabulated.