This fly very much resembles a bee and is an example of Batesian mimicry, which is for a harmless organism to resemble a dangerous one to avoid predators. Size is 9 to 11 mm. Thorax distinctly bicolored (gray on front half, black on rear half); scutellum bright yellow, much brighter than the pale yellow of other Eristalis species. This combination of characters is diagnostic.
Found on flowers from about April to November.