The haltere, the nub below the wing, takes the place of the second wing on each side, for flies. Its movements help the fly maneuver in the air. Some pollen sticks to the fly. Taken on the ridge, off-trail during an ant survey, south of Road F and east of Trail 10. 5/7/2016, 11:41:35 am. The fly was intent on its business, and let me get close and take many photos.