I thought I'd try you guys before I hit the Butterfly Gardening forum. I spent all morning trying to ID this and I'm very frustrated. :)

This weekend I found that my Helichyrsum plants are full of webby gunk that pulls the leaves together. I pulled one open and saw a tiny, curled up black caterpillar with spines - very yucky. Later I found one larger one, though, that was beautiful. It was about an inch long, black, with a pattern of two horizontal gold stripes and two white dots repeating down its body. They don't seem to be eating the licorice plants much - they only seem to be eating the occassional leaf that's big enough to have turned green (rather than silver). Anyone seen anything like this?

I have licorice plants in two different containers that are widely separated, and I've found these on both. They haven't spread to anyting else in those containers. I'm not sure if this caterpillar feeds on those specifically or if it came in the soil - I got all the licorice plants from the same place.

I'm trying to figure out if I should try to handpick these, or just leave them alone.