Cheilosia albitarsis and Cheilosia ranunculi are very similar and can often only be safely determined by detailed examination; for this reason the term 'sensu lato' or 'in a broad sense' is often used.  They are robust with a short broad abdomen. In sunlight the thorax may be seen as metallic dark blue/green. The abdomen is more of a duller grey/bronze colour.  

If you have not been able to key your specimen out as either C albitarsis or C ranunculi, please submit it as this 'sensu lato' option

These species are often found in damp meadows, marshy areas, woodland clearings or well-shaded verges and are associated with buttercup.

April to August

Adult females may sometimes be found landing on a buttercup leaf, walking to the tip and then underneath in order to lay an egg.

As an aggregate of the two species, this appears common in Leicestershire and Rutland.