A dark bodied hoverfly with red brown hairs. C. grossa is very similar to C. albipila but on close examination C. grossa will be found to have black antennae.  

Areas where thistles are common, damp meadows woodland rides etc. 

March to May – peaking late March and early April. 

Larvae develop inside the stems of thistles. 

Widespread and fairly frequent in Britain.  

Fairly frequent in Leicestershire and Rutland.