Wing length: 5.5 to 8.25 mm

The key identification feature of this hoverfly is the arched and swollen hind femur with a large triangular projection on its lower surface near the apex. (Visible is several photos below, including an enlargment.) The projection has small black spines along its hind edge.

The abdomen has orange markings on tergites 2 and 3, covering the entire lateral margins in males, but reduced in females, sometimes to paired spots.

This fly prefers marshy areas and fens, particularly where reedbeds are present.

May to October, with the greatest numbers being on the wing in June and July.

Still unclear. The larva is believed to develop in wet debris such as reedbed litter.

Widespread in Southern and Eastern England but local. It tends to become coastal further north, reaching as far as southern Scotland.

Local.