...once through the slit, the syrphid pushes its head and proboscis deeper into the cavity between the keel petals to access nectar and/or pollen. The orange, pollen-covered anthers are between the entry slit and the nectaries, and the flower "hopes" some pollen will dust the syrphids face and body and eventually be transfered to the stigma within the keel of a flower on another Psorothamnus polydenius bush.

The syrphid seems to really be applying itself. Note how its right calypter (or "squamma") is folded upward out of the plane of the rest of the wing, and how the abdomen is curled. As with other BugGuide contributors, I've noticed how syrphids will often continuously curl and uncurl their abdomens as they feed on a flower. I wonder if it's a way of helping pump oxygen through their spiracles into and out of their tracheae, to assist "breathing" during their energetic feeding activity?