The larva of Athalia liberta [1, 2], a Sawfly (SYMPHYTA) on Garlic mustard (Alliara petiolata), a host plant of this species.

Literature
1 Nederlands Soortenregister2 Sawflies.org.uk, Spreadsheet of larval foodplants
Athalia liberta
Alliara petiolata (Garlic mustard)The larva of Athalia liberta [1, 2], a Sawfly (SYMPHYTA) on Garlic mustard (Alliara petiolata), a host plant of this species.
Literature
1 Nederlands Soortenregister