A female hoverfly from a couple of years ago: a Syrphus sp, probably Syrphus vitripennis (Diptera: Syrphidae). The mainly black hind femur distinguishes the females of this species from those of S. ribesii and S. rectus. The lack of hairs on the eyes distinguishes this species from S. torvus. Syrphus males are harder to distinguish from photos.
Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2010-06-09.