Sawfly larva?

Sawfly larva?

Observation - Sawfly larva? - UK and Ireland. Description: A black caterpillar like larva seen sitting on yellow flag iris (I think) near the coast. I don't know if it was feeding on the iris - I think probably not. The ground nearby was quite grassy and marshy as a freshwater stream fed down the beach. There was

A black caterpillar like larva seen sitting on yellow flag iris (I think) near the coast. I don't know if it was feeding on the iris - I think probably not. The ground nearby was quite grassy and marshy as a freshwater stream fed down the beach. There was also some scrubby trees nearby.