Appearance
large bee flies, of about 14 mm, sometimes larger, up to 22 mm. The proboscis is short. The head is large and only loosely attached to the thorax. The antenna are small and well separated. Wings are large and boldly patterned; abdomen patterned (often banded) with white or pale scales on segment 6 and 7 or on each segment.wing patterns discussed here - http://bugguide.net/node/view/198225#see_also
References:
Some text fragments are auto parsed from Wikipedia.
https://en.wikipedia.org/wiki/Exoprosopa