Amended key to the Fennoscandian Tricimba species

1’ Ocellar triangle with a shiny spot before the anterior ocellus; postpronotum yellow............................... T. humeralis (Loew, 1858)

- Ocellar triangle entirely dull; postpronotum concolour with scutum.................................................................................................2

2’ Two to three longitudinal grooves in the scutum more or less visible; apical scutellar setae slender; scutellum entirely brown or yellow apically; body pilosity dark or yellow ....................................................................................................................................3

- Five deeply impressed longitudinal grooves in the scutum; scutellum concolour and apical setae stout; cell br widened in the middle........................................................................................................................................................... T. lineella (Fallen, 1820)

3’ Three visible longitudinal grooves in the scutum; apical scutellar setae approximated; body pilosity pale or dark; male cercus slightly longer than wide in terminal view, with a quadrate connection between the male cerci ................ T. cincta (Meigen, 1830)

- Two almost indistinct longitudinal grooves in the scutum; apical scutellar setae widely apart; body pilosity pale; male cercus wider than long in terminal view, with a triangular connection between the male cerci .................................................. T. atipica sp. nov.