Redescription of Hemibrycon orcesi Böhlke, 1958 and H. polyodon (Günther, 1864) (Pisces, Characidae), with a key for the species of Hemibrycon from Ecuador. Hemibrycon orcesi is readily distinguished from its congeners by its 13 to 16 teeth on maxilla, base of caudal fin scaled, 34 to 36 scales on lateral line with pores and 17 to 18 branched anal fin rays. H. polyodon is distinguished from its congeners by simple and branched dorsal fin rays of equal length and shape of humeral spot.