Since the publication on Notonectidae of the Antilles (NIESER 1967), the author received various Notonectidae for identification. Material from the region considered here (Antilles, Central and N. America) came from the following sources: more material from the various voyages of Dr. P. WAGENAAR HUMMELINCK to the West Indies; unidentified material from the Copenhagen, Leiden and Oxford Musea and the Zoological Institute at Leningrad. The author likes to express his thanks to Dr. P. H. VAN DOESBURG, Jr (Rijksmuseum van Natuurlijke Historie, Leiden); Dr. I. M. KERZHNER (Zoologitsheskij Institut, Leningrad); Dr. I. LANSBURY (University Museum, Oxford); Dr. N. MØLLER ANDERSEN (Zoologiske Museum, København), and Dr. P. WAGENAAR HUMMELINCK (Zoölogisch Laboratorium, Utrecht) for permission to study the material in their charge. Mrs. E. DE GROOT-TAAT (Rijksuniversiteit, Utrecht) kindly read the greater part of the manuscript, correcting various inaccuracies in the English.