Not a caterpillar

Dead heading a rose I noticed a caterpillar. On closer inspection there were others.

A little research told me that they are not in fact caterpillars, but larvae of the large rose sawfly. Sawflies are not true flies, but a group in the large insect family that includes bees, wasps and ants.

I have removed those I could see, otherwise the plant is at serious risk of defoliation,.