Muscina levida and prolapsa

Muscina levida and Muscina prolapsa are two species of dark grey muscid fly both with convergent veins at the wing-tip and a reddish tip to the scutellum.  M. prolapsa is distinguished by having reddish palps and antenna base and by its wing veins being more tightly convergent.  In the Reading area, at least, M levida is about 5 times as common as prolapsa and male levida can often be found sunning themselves on tree trunks in late autumn and early winter. What I hadn't realised until I made the following plots was that prolapsa shows a marked preference for springtime while levida prefers summer and autumn.

These plots are based on flies collected mainly in the Reading area since 2014.