Abstract
Lactistomyia koreana sp. nov., the first species of the genus Lactistomyia Melander, 1902, recorded from the Palearctic Region, is described based on four female and one male specimens collected in Korea. Our discovery of the Lactistomyia species from Korea documents an unusual trans-Pacific distribution of the genus previously known only from the Neotropical Region. The systematic affinities of the new species with the Neotropical Lactistomyia is supported by a phylogenetic analysis based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. An updated checklist and identification key to the world species of Lactistomyia is provided, and morphological characters distinguishing the new species from its congers are discussed. Lactistomyia koreana sp. nov. is morphologically most similar to Lactistomyia paranaensis Ale-Rocha, 2008, from Paraná, Brazil, for which holotype images are presented for comparison. In addition, the generic placement of Lactistomyia polita Melander, 1928, from the Philippines-which was previously transferred to Syndyas Loew, 1857, and was given the new name, Syndyas melanderi Ale-Rocha, 2008-is discussed based on examination of holotype images. These findings confirm L. koreana sp. nov. as the first unequivocal record of Lactistomyia from the Old World.