All The Small Things #13 (Chomp)

The dog rose has a number of these caterpillars on it now which are chomping at the fresh new leaves. I have left them alone as there is no way they are going to eat the whole bush, there's not enough of them.

Besides the birds may want to chomp them in turn, and I have no idea what species of butterfly or they belong too. It might be one that is trouble for all I know.

If anyone can ID it it would be awfully nice.