This worm/caterpillar has about wiped out a Lysimachia autropurpurea plant within 2 or 3 days it seems. Of course there are *many* of them. I know that on my Anaphalis I sprayed Sevin before I knew the caterpillars eating the plant were buckeye butterflies. I'd hate to do that with these, but I also hate to lose all my Lysimachia plants as it's killing them.

Sorry, couldn't get a real clear photo: Worm is longer than an inch and has a bluish cast:

Try looking up:
Monostegia abdominalis
and see if that's the one.

Thanks. May very well be. Inspected closer with my eyes, and there appears to be a kind of stripe down each side, darker than the rest of the color. The only thing that doesn't seem the same from what's on mine to the other photos, is the large amount of white on the underside, or crawlers, or whatever that portion is called.