Alder Sawfly caterpillars

Alder Sawfly caterpillars

Observation - Alder Sawfly caterpillars - UK and Ireland. Description: Chomping through Common Alder, and raising their tails when disturbed. These must be the final larva

Chomping through Common Alder, and raising their tails when disturbed. These must be the final larval instars: younger ones, apparently, are covered in a thick white layer of powder that makes them appear to be bird-droppings.