Notes on the genus Harmonicon F.O.P.-Cambridge, 1896 (Araneae, Dipluridae) with description of a new species from French Guyana.

Information on the genus Harmonicon F.O.P.-Cambridge, 1896, a key to the species and a new diagnosis differing from the one in Maréchal and Marty (1998) are provided. A new species is described: Harmonicon oiapoqueae differing from other species of the genus by the morphology of the posterior sternal sigilla, the more recurved, inverted U-shaped fovea, the amount and arrangement of maxillary cuspules, a single row of teeth on the claws of the palpal tarsus, longer and more slender legs III and IV in females, longer embolus, thinner bulb, and longer, more slender legs in males. The status of the putative junior synonyms of Harmonicon, Pseudohermachura Mello-Leitão, 1927 and Prosharmonicon Mello-Leitão, as well as the two species formerly assigned to Harmonicon, Harmonicon nigridorsi Mello-Leitão, 1924 and Harmonicon riveti Simon, 1903, is discussed.