The hind metatarsus is narrowly orange at base and has a very broad black band and then narrowly orange at tip in all specimens identified as Platycheirus hyperboreus. This may be a feature to look for.

Moved from Platycheirus.

From Young et al 2016:

1: female -> 79
79: no strong corner at oral margin -> 105
105: some tergites with pale spots -> 108
108: all femora yellow at base -> 110
110: yellow spots rectangular -> 112
112: tergite 5 pale -> 114
114: pale spots on T2 reduced, pale spots broader than long, dark rings on hind femora and tibia -> 115
115: strong silver pruinosity -> P. hyperboreus

Moved from Melanostoma mellinum.
It was never certain that it was Melanostoma

Platycheirus..... female.
Front tarsi flattened.
Melanostoma has the antennae partly orange, they are totally black here.

Moved from Melanostoma.

I agree with Paul, this should be a Melanostoma.
However, it is not the familiar (to me) M. mellinum, because it's abdominal spots are different.
So unfortunately I can't tell you which species!
Greetings,
Gerard Pennards

I am quite certain that this is a species of Melanostoma. Maybe Gerard can tell us which one. ;-)

Paul

http://www.diptera.info