Pipiza puella,[2] the sumac gall pithead, is a species of syrphid fly observed in eastern and Central United States, Canada and Norway. Hoverflies can remain nearly motionless in flight. The adults are also known as flower flies for they are commonly found on flowers from which they get both energy-giving nectar and protein rich pollen. Larvae when known are aphid predators.[3][4]
This article incorporates text from this source, which is in the public domain: Williston, S.W. (1887). "Synopsis of the North American Syrphidae". Bulletin of the United States National Museum. 31: 1–335.