Congratulations! What a beauty. My black swallowtail is in his fifth instal, and I think he's getting ready to pupate (but he hasn't regurgitated the food yet). He's been wandering all over the place though, so I think he's getting close. This is my very first butterfly (other than the painted lady kit I did with my son which is how I got hooked onto butterflies in the first place), which I found in my garden. I've been checking daily for more cats or eggs, but so far, he's my one and only. And I worry constantly that he's not going to make it. He spent over a day during the last molt, and I was constantly worried that that was the end for him. So glad to see your butterfly doing well!

chezmonmi, the first year I saw swallowtail cats appear on my dill, a wasp had eaten them all by the end of the day! I don't mean to be shocking, but since then, I decided to try to rescue if I could. So, I started saving containers that very day. On the bright side, the wasps were not nearly so prolific this year, so I could let the cats get bigger before bringing them in. There have been seven so far and two new batches (or three) are on the dill. I think I need to plant a second patch of dill!

I'm also in NJ. They should overwinter; mine have normally mostly overwintered, but this year was the first year that quite a few pupated early on and eclosed within 2 weeks. I currently have 6 caterpillars and 5 should be pupating any day now. They'll overwinter in my screened cage on my deck, which is where I put my potted plants that the BSTs laid the eggs on. I will usually only cover it with a normal bed sheet once the bitter winds kick in, but other than that, I don't pamper them. I do have a piece of plexiglass on top, ventilated somewhat, just so that the screen doesn't cave in from the snow. Last year I had a bunch of them that overwintered and eclosed in May and June. A few still haven't eclosed, but I'm thinking those darn parasites got to them and probably can't overwinter. I'm going to leave them be since someone here said a BST took something like 19 months to eclose. But I don't think I'll be that lucky...

Maybe I should put the plant on a stand, so that they don't walk off. I think I will leave the one pot inside, as it gets plenty of light and the plant was in a part of the yard where it was out in the open. I have another pot of parsley that is in a more protected spot, and I noticed two very small caterpillars on that today, but I will leave that pot outside. I do not know about overwintering - we do not really have winter here - never a frost, and normally it does not get below 45° in the winter. Last winter was rather warm, and it only got below 50° a couple of times, but I think this winter will be colder and have lows in the 40s on the colder nights. I don't think temperature is an issue with this butterfly, however, since they live in colder climates than mine. I will be very careful when harvesting the parsley, but I would rather than the butterflies than the parsley, although I think I can have both. I guess I should plant some more, since it does well here in the winter. I am curious about whether they will wander off to form their chrysalis. Thanks for the link - I will have to do some more research on raising these butterflies, as they are one of my all time favorites. The yellow swallowtails are fairly common here, but I think this might be a black version. What would an Eastern Swallowtail be doing in California?