The types of nominal species of Diapriinae in the collection of the Natural History Museum, London, are catalogued. Lectotypes are designated for the following taxa: Diapria peraffinis Ashmead, 1896; D. smithii Ashmead, 1896; Galesus bipunctatus Ashmead,1894; G. (G.) foersteri var. nigricornis Kieffer, 1911; G. sexpunctatus Ashmead, 1893; G. walkeri Kieffer, 1907; Idiotypa nigriceps Kieffer, 1909; I. nigriceps Kieffer, 1911; I. pallida Ashmead, 1893; I. pallida Ashmead, 1894; Paramesius angustipennis Kieffer, 1911; P. cameroni Kieffer, 1911; Phaenopria cameroni Kieffer, 1911; P. halterata Kieffer, 1911; P. magniclavata Ashmead, 1896; Tropidopsis clavata Ashmead, 1893; T. clavata Ashmead, 1894. New combinations are proposed: Aneuropria bifurcata comb. nov. for Mantara bifurcata Dodd, 1920; Basalys quadridens comb. nov. for Microgalesus quadridens Kieffer, 1912; Coptera cratocerus comb. nov. for Galesus cratocerus Cameron, 1912; Coptera sexpunctata comb. nov. for Galesus sexpunctatus Ashmead, 1893; Doliopria magniclavata comb. nov. for Phaenopria magniclavata Ashmead, 1896; Spilomicrus aterrimus comb. nov. for Hoplopria aterrima Dodd, 1920; Spilomicrus campbellanus comb. nov. for Antarctopria campbellana Yoshimoto, 1964; Spilomicrus coelopae comb. nov. for Antarctopria coelopae Early, 1978; Spilomicrus diomedeae comb. nov. for Antarctopria diomedeae Early, 1978; Spilomicrus helosciomyzae comb. nov. for Malvina helosciomyzae Early & Horning, 1978; Spilomicrus insulae comb. nov. for Malvina insulae Early, 1980; Spilomicrus latigaster comb. nov. for Antarctopria latigaster Brues in Tillyard, 1920; Spilomicrus punctatus comb. nov. for Malvina punctata Cameron, 1889; Spilomicrus rekohua comb. nov. for Antarctopria rekohua Early, 1978; Trichopria bouceki comb. nov. for Oxypria bouceki Masner, 1959; Trichopria nigriceps comb. nov. for Tropidopria nigriceps Ashmead, 1894; Trichopria nigriceps comb. nov. for Xyalopria nigriceps Kieffer, 1907; Trichopria spinosiceps comb. nov. for Acidopria spinosiceps Dodd, 1920; Trichopria walkeri comb. nov. for Diapria walkeri Dalla Torre 1890. New replacement names are proposed: Coptera mosselensis nom. nov. for C. nigricornis Nixon, 1930 preocc.; Coptera pijiguaorum nom. nov. for C. sexpunctata Montilla & García, 2008 preocc.; Spilomicrus kozlovi nom. nov. for S. punctatus Kozlov, 1978 preocc.; Trichopria fluminis nom. nov. for T. nigriceps (Kieffer, 1907) preocc.; T. thermarum nom. nov. for T. nigriceps (Kieffer, 1913) preocc. New specific synonyms are proposed: Basalys cursitans (Kieffer, 1911) = B. pedisequa (Kieffer, 1911) syn. nov. (the former removed from synonymy with B. parvus Thomson, 1858); B. iphicla Nixon, 1980 = B. macroptera (Kieffer, 1911) syn. nov.; Coptera bipunctata (Ashmead, 1894) = C. sexpunctata (Ashmead, 1893) syn. nov.; Idiotypa nigriceps Kieffer, 1911 = I. nigriceps Kieffer, 1909 syn. nov.; I. pallida Ashmead, 1894 = I. pallida Ashmead, 1893 syn. nov.; Psilus nigricornis (Kieffer, 1911) = P. fuscipennis (Curtis, 1831) syn. nov.; P. walkeri (Kieffer, 1907) = P. fuscipennis (Curtis, 1831) syn. nov.; T. bouceki (Masner, 1959) = T. conotoma (Kieffer, 1911) syn. nov.; Trichopria halterata (Kieffer, 1911) = T. halterata (Kieffer, 1909) syn. nov. New generic synonyms are proposed: Antarctopria Brues in Tillyard, 1920 = Spilomicrus Westwood, 1832 syn. nov.; Malvina Cameron, 1889 = Spilomicrus Westwood, 1832 syn. nov.; Mantara Dodd, 1920 = Aneuropria Kieffer, 1905 syn. nov.; Microgalesus Kieffer, 1912 = Basalys Westwood, 1833 syn. nov.; Xyalopria Kieffer, 1907 = Trichopria Ashmead, 1893 syn. nov. (Xyalopria is removed from synonymy with Megaplastopria Ashmead, 1903). A brief account of some aspects of the history of these types is given.