Since the publication of the writer's “Revision of the Aphelininæ of North America” (Bulletin 1, Technical Series, U. S. Department of Agriculture, Division of Entomology, 1895), the discovery of new forms, and especially of new genera, has been of very infrequent occurence. Species have been received from all parts of the world, owing to the extraordinary and world-wide development of interest in scale insects, which are the principal hosts of the Aphelininæ, yet nearly all of the forms thus received have been species already described, which have been carried with their hosts upon live plants to many different regions. It is, therefore, interesting to discover a new genus, even from a country like Chile, whose parasitic Hymenoptera are so little known. A most interesting feature of the discovery is that the new genus was reared from Aspidiotus hederœ (nerii) together with three of the cosmopolitan forms, namely, Aspidiotiphagus citrinus (Craw); Coccophagus immaculatus, How., and Prospalta aurantii, How. The writer is indebted to Mr. Edwyn C. Reed, of Rancagua, Chile, for this sending, as well as for many other favours.