<em>Semium brailovskyi</em>, new species (Heteroptera: Miridae: Phylinae: Semiini) from Baja California, with an updated key to species

Semium brailovskyi, new species, is described from Baja California Norte, Mexico. The host is reported as Euphorbia misera (Euphorbiaceae). Color habitus images of male and female specimens, line drawings of the male genitalia, a key and distribution map to all Semium species are provided.