REVISION OF NEARCTIC SPECIES OF CEROMYA ROBINEAU-DESVOIDY (DIPTERA, TACHINIDAE)

Nine species of Ceromya Robineau-Desvoidy (Diptera: Tachinidae: Siphon ini) are recognized in the Nearctic region, including four new species , and one described species known previously only from the Palearctic region. The species are arranged into three species groups, with each group hypothesized to be monophyletic and each containing extralimital members. The three species groups and nine Nearctic species are as fo llows: the bicolor-group with C. bicolor (Meigen) (a Holarctic species newly recorded from the Nearctic region); the flaviseta-group with C. ontario (Curran) and C. palloris (Coquillett); and the americana-grou p with C. americana (Townsend), C. balli sp.nov. (type-locality Masham Township, Quebec, Canada), C. elvii (Walton), C.flava sp.nov. (type-l ocality Masham Township, Quebec, Canada), C. oriens sp.nov. (type-loca lity Masham Township, Quebec, Canada), and C. occidentalis sp.nov. (ty pe-locality Lakelse Lake, British Columbia, Canada). The bicolor-group has an Old World - Nearctic distribution, the flaviseta-group has an European-Nearctic distribution, and the americana-group has a Neotropi cal-Nearctic distribution. Adults of the nine Nearctic species of Cero mya are keyed and described, known hosts are listed (including correct ions to published records), distributions are mapped, and taxonomicall y useful features are illustrated.