Kelsey, using the Ontario Syrphidae guide this looks much closer to Blera armillata than B. nigra, at least to my eye. Leg colouration and frons/face colour seem much closer to armillata, a female.

I've taken another look - thanks for the heads up! It does look closer to armillata in the leg and lower face coloration. On the other hand, the frons on this fly seems largely black (though given Blera's extended antennal base, it's hard to tell exactly where the cutoff lies), and it does have a slight facial stripe, which is consistent with nigra but not armillata.

This fly's abdomen is entirely yellow pilose, which would make it Blera armillata hunteri (see Barkalov and Mutin 1991), which Curran (1953) says should be east of the Rockies, but this specimen is in the middle of the Rockies.

In Barkalov and Mutin's key, this keys to Blera armillata hunteri, but they've put B. nigra into Lejota due to the lack of facial tubercule among other things, and this fly does have a tubercle, so that supports B. armillata hunteri.

I'll move it back to genus for now and we'll see if we get some other thoughts. Thanks!