A review of the genera of Neotropical Encyrtidae (Hymenoptera : Chalcidoidea) W LIB-, John S. Noyes Department of Entomology, British Museum (Natural History), Cromwell Road, London SW7 5BD Contents Synopsis 107 Introduction 107 Notes on terms and measurements 108 Abbreviations Ill Key to genera (females) Ill Key to genera (males). . . . . . . . . . . . .150 Notes on genera 169 Host index 236 Proposed new synonymies 238 Proposed new combinations 238 Lectotype designations ............ 239 Acknowledgements 239 References 239 Index 246 Synopsis Keys are presented to both sexes of the 148 genera* of Encyrtidae known from the Neotropical region. Notes on each genus are also included; these give information on known world distribution, number of species known, distribution of the genus within the Neotropics, a list of species known from the region, notes on biology, systematic placement and references to original descriptions, redescriptions, revisions or other useful papers. Lectotypes are designated for six species, 19 new genera and 18 new species are described, 16 new generic synonymies and 1 new specific synonymy are proposed. Introduction The Neotropical Encyrtidae, probably more diverse than those of any other part of the world (except perhaps Australasia), have been little studied beyond the work of De Santis (1964) and remain poorly known. So far 148 genera* and 380 species are recognized as occurring in the region covered by the present study, i.e. South and Central America, including associated islands and the whole of Mexico, the Antilles from Trinidad to Cuba, and Bermuda; it is very likely that this is only a small proportion of the number that actually occur there. Over 20 000 specimens comprising well over 500 species have been examined in the course of this study; many of these species are undescribed and belong to unknown genera. Nineteen genera are here described as new and as many as twice this number are ignored because of the condition of the material or because they are represented by single specimens. It is possible that a number of the genera considered here as valid may eventually fall in synonymy when more is known about the family as a whole. Some may have already been described by Girault from Australia, since there is a close similarity between the eastern Australian and Neotropical encyrtid faunas, but this , Bull. Br. Mus. nat. Hist. (Em.) 41 (3): 107-253 Issued 30 October 1980 * Note added while this paper was in press. De Santis (1979) also includes the following genera not dealt with in this review: Asitus Erdos, Boucekiella Hoffer, Cerapterocerus Westwood, Platencyrtus Ferriere and Tachinaephagus Ashmead.