For the opportunity to examine the material on which the following descriptions are based I am indebted to the courtesy of Dr P. A. Buxton and Miss E. Sikes of the London School of Tropical Medicine, where the life-history of certain fleas is being studied. A detailed examination of the parasite showed it to be referable to the Pirenine tribe of the Miscogasteridae—a family of Chalcidoid wasps. The genus and species appeared to be new. The fact, however, that the parasite had been bred from a species of flea known to have been recently introduced into Britain suggested the advisability of comparison with American representatives of the Pirenine group. This has now been done by my friend Mr A. B. Gahan of the Bureau of Entomology, Washington, D.C., to whom my hearty thanks are due. As the result we are agreed that a new genus is required. Bairamlia n.g. has obvious affinities with Pirene Hal., but differs in antennal, neurational and propodeal characters. Ecrizotes Forst. (fide A. B. Gahan) may also be a nearly related genus. genus. As regards the species, I am satisfied that it is very different from anything described by Walker of which material is still extant in the British Museum. Mr Gahan, however, tells me that Pirene marylandensis Gir. (Canad. Ent. 48, p. 116, 1916) is a congeneric though distinct species.