Searching in the ancient: Old museum type material reveals two remarkable undescribed species of Aulacidae (Hymenoptera: Evanioidea) from the Oriental Region

The study of old type series stored at The Natural History Museum, London, allows the designation of lectotype and paralectotypes, and redescription of Pristaulacus erythrocephalus Cameron, 1905 and Pristaulacus fasciatipennis Cameron, 1906. In addition, the male of the latter species is described for the first time. Two new large and remarkable overlooked species, previously hidden in the Cameron's type material of the above-mentioned species are described and illustrated, namely Pristaulacus cephalocarinatus Turrisi, sp. nov. from Indonesia (West Kalimantan) and Malaysia (Sarawak), previously treated under P. erythrocephalus, and Pristaulacus nataliae Turrisi, sp. nov., from Malaysia (Sarawak), previously treated under P. fasciatipennis. In addition, a brief taxonomic account of the Pristaulacus flavipennis species group, which comprises six species (including P. erythrocephalus and P. cephalocarinatus sp. nov.), is presented along with a key to species.