Full reference: F. M. Hull. 1938. Fossil Insects from the Creede Formation, Colorado Part 1. Diptera family Syrphidae. Psyche 45:116-117
Type specimen: MCZ 3949, an exoskeleton. Its type locality is Creede MCZ collection, which is in an Oligocene crater lake shale in the Creede Formation of Colorado.
Average measurements (in mm): body length 10.0, wing length 7.96