It's a cross-striped cabbageworm, Evergestis rimosalis, I believe. Food plants in the cabbage family. The fact that it is on Thalictrum is probably indicative that it is preparing to pupate, and is wandering around to find a suitable location. Susan Here is a link that might be useful: cross-striped cabbageworm

Thanks Sherry! I was secretly hoping for something more exotic but we're usually not that lucky this far north. It has been a really slow butterfly year so far. I still haven't seen any eastern or black swallowtails. I finally broke down and went to the monarch waystation at the lake to get monarch eggs. We have tons of large common milkweed and it remains empty. Maybe I'll start eating it so it doesn't go to waste ;)

Yes, I put chrysalides and moth cocoons/pupae outside in winter so that, assuming temperatures influences emergence time, they'll emerge at the right time. I don't use much heat in winter, but my house is still warmer inside than outside, usually. Up north, I imagine it's much warmer inside than out. Of course, you'll need to put the container in a safe place where mice and/or other critters can't get to it. I notice that there's a black area on the caterpillar, also there's brown liquid around it. I'm hoping that the brown liquid is the purging the cat did before going to pupate and not a leak. If the caterpillar is leaking fluid from its body, it'll die. Good luck, let's hope everything's okay! Sherry

I think the first picture shows pink striped oakworms. When they reach the last instar, you'll be able to see the pink better. They make a pretty moth. Maybe Larry will know what the second picture is - I've looked through a few of my books and can't find it, but it's probably some type of tiger moth. Sherry