A Revision of the nivea Group of the shore-fly genus ditrichophora cresson (diptera: Ephydridae)

Abstract

Species of the nivea group (genus Ditrichophora Cresson) are revised. The group now includes four species of which one, D. gulkana (Alaska and Mongolia), is newly described. The group is now known to have a Holarctic distribution with two species, D. gulkana and D. nivea, being the first reported from the Nearctic Region. Another Asian species, D. brunnicosa, previously placed in Diclasiopa, is transferred to this group (genus Ditrichophora) and is also reported from Mongolia. To facilitate identification of these rare species, we have included diagnoses of the tribe, genus, and species group and have also provided an annotated key to Holarctic genera of the tribe Discocerinini and to species of the nivea group within Ditrichophora. We also provide the first illustrations of male terminalia for all included species.