Review of the family Rotoitidae (Hymenoptera : Chalcidoidea), with description of a new genus and species from Chile

A new genus and species of Rotoitidae, Chiloe micropteron Gibson and Huber, is described from females and one male from Chile. The taxon is the second known genus and species, and the male is the only one known for the family . Scanning electron micrographs illustrate external and internal structure of C. micropteron females, and external structure of Rotoita basalis Boucek and Noyes, the other described genus and species. The original description of the axillae, prepectus and fore wing venation given for R. basalis is a mended and additional features are described based on re-examination of thr ee specimens studied by Boucek and Noyes and study of one additional female . The family diagnosis is modified to include features of Chiloe and some p reviously undescribed characters that are used to infer relationships withi n Chalcidoidea. A six-segmented clava in females and possibly a five-segmen ted clava in males support monophyly of Rotoitidae. A 14-segmented antenna in females, structure of the prepectus, and a single site of origin from th e axillar phragma for the mesotergal-mesotrochanteral muscle could indicate Rotoitidae as the basal lineage of Chalcidoidea, whereas ovipositor struct ure indicates Rotoitidae as the second-most basal lineage, with Mymaridae b eing the basal lineage.