7-9mm with a red band over the dorsal abdomen but with significant white markings on the sides or underneath of the abdomen.

A. acupariae is a similar size, found in similar habitats and also early in the year, but this lacks the white markings on the abdomen and the red band extends underneath.

A side view is needed for ID. Look for the white lateral band along the abdomen or white beneath.

Hedgerows and wooded places

April to June

Larvae feed on Galium species.

Common in Britain.

Common in Leicestershire and Rutland.

https://www.sawflies.org.uk/aglaostigma-fulvipes/