It occurs in a variety of colour forms, sometimes with a red-marked thorax, sometimes all black.

This species has a red ID rating and unless identified by a known expert you must provide a satisfactory explanation of how it was identified for the record to be accepted.

Around Oak, often in broadleaved woodland.

Spring to summer.

A local species, with most records coming from southern Britain.

Infrequent in Leicestershire and Rutland.

https://www.sawflies.org.uk/mesoneura-opaca/