Syrphid Fly - Mallota sp.
Diptera Family Syrphidae
Live adult Syrphid fly photographed in the wild at Winfield, Illinois, USA.
  Syrphid Fly - Mallota sp.
This female Syrphid fly is undoubtedly the largest fly in this family I've ever seen - nearly 20mm from antennae to wingtips. I'm not sure if this fly is mimicking a bumblebee (probably) or mimicking a robber fly mimicking a bumblebee.

Habitat: Deciduous forests and edges; adults frequent flowers. Males congregate at higher elevations, i.e. hilltops, bluffs, etc. and wait for females to arrive. [1]

Syrphid Fly - Mallota sp.

This female Syrphid fly is superb bumble bee mimic.
References
  1. Bugguide.net, Genus Mallota
              
 
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