A newly recorded species of Philostephanus Distant, 1909 from Korea, P. ulmi (Kerzhner, 1979), is reported with brief taxonomic notes on the Korean Philostephanus species. Morphological keys of the Korean Philostephanus species are provided with the photos of adults and female genitalia for each species.

The genus Philostephanus Distant 1909 belongs to the family Miridae, including 23 species from the eastern Palearctic and the Oriental regions. They are characterized with a relatively large body, brown or fuscous coloration, rather symmetrical parameres of male genitalia, and unique structures of female genitalia. Especially, the respective structures of female genitalia exhibit distinct interspecific variation, which is uncommon in other genera of Miridae, so they are used as key characters in identification and phylogenetic study. Most of members are known to inhabit deciduous trees, and their feeding habits are considered predominantly predaceous although some species are known to use some deciduous trees as their breeding hosts (Yasunaga & Schwartz, 2007). Presently, two species are reported in the Korean fauna (Kwon et al., 2001). During our study, we found one newly recorded Philostephanus species from Korea, P. ulmi (Kerzhner 1979), which is distinguished from other Korean congeners by speckled hemelytra with pale portions. In this study, we provide taxonomic information on P. ulmi and review briefly the Korean Philostephanus species with morphological keys and photos of specimens.