Taxonomy of Bradysia Winnertz (Diptera, Sciaridae) in the Northern Holarctic, with the description of four new species

Four species of Bradysia Winnertz (Diptera, Sciaridae) from the Northern Holarctic are described and illustrated for the first time: Bradysia bigeminata sp. nov. (Finland, Canada), B. falciceps, sp. nov. (Finland, Canada), B. oelandica sp. nov. (Sweden) and B. plusiospina sp. nov. (Finland). A few Bradysia species, described previously and now found in Northern Europe, are also redefined and illustrated.