A very boldly marked, medium-sized hoverfly.   It is always worth checking this species for the dark form of the much rarer C.elegans or the even rarer C. vernale. There is also a very rare species of southern heathland, C. vernale, which resembles a small C. festivum with the yellow bars of the tergites much straighter. 

Tall grassland and open scrub. Adults visit a variety of flowers, but especially umbellifers and thistles.

Late May to the end of August.

The larvae are probably associated with ant-attended root aphids.

Frequent in  in southern Britain.

Occasional in Leicestershire and Rutland.