Moved from Sphaerophoria novaeangliae.

Vockeroth describes novaeangliae as NOT having the tergite markings narrowing at sides and the markings on tergite 5 if present restricted to two small spots near sides of tergite.
In this image tergite 6 is mainly orange with a small black triangle on anterior margin at middle and two black spots nearer to posterior margin toward sides of tergite which is typical of contigua but Vockeroth describes contigua as having yellow face without black facial stripe, with at most a pale brown stripe. I think this is an aberrant contigua but to be safe I think this should be placed just in Sphaerophoria.
Vockeroth`s image of novaeangliae shows tergite 6 black with a white/ yellow border on the posterior margin as in BugGuide image 1472737 and this image, 1472737 and the image in Skevington`s Guide has the hind femur darkened toward tip. I don`t know if this is significant.

Moved from Sphaerophoria.

I would say Sphaerophoria...