This is the first of what I think is a member of the Pyreferra problem-caterpillar clan: absolutely lurid, almost incandescent moths-to-be that thrive on a non-stop diet of Witch Hazel leaves. Given how many members of the Hamamelis fraternity we have around here, I suppose the caterpillars are entitled to nosh on a few. I doubt they'll do the plants any real harm. The moths themselves, known as Sallows, are fairly nondescript, but their kids more than make up for any adult drabness. When the Pyreferra caterpillars are at work, the aptly named "fire makers" are impossible to ignore, as they burn brightly on the leaves.