..."and really thick, furry brown-and-black ones": a fairly good description of the woolly bear caterpillar. The brown is usually more rust-red.

The small green caterpillar might be some kind of geometrid moth, hard to tell without a photo.

Here's a picture of the aforementioned mystery cocoon (I apologize if the quality isn't so hot - my camera is pretty lousy). There's a penny there for size comparison - this little guy isn't very big.

I also notice some days it never moves and other days (like a couple days ago), it wags its tail at me a lot. When I took this shot, it only moved once and I was sliding it all over the sink top. But a couple days ago, if I moved its jar even a tiny bit, it was violently wagging its tail. Strange.

Thoughts? What you see is the top of the cocoon - the bottom is covered in silk.

Lucky you! it looks like a Black Swallowtail to me

Here is a link that might be useful: Pupa of Black Swallowtail

Ooo, thanks for the info, NaturesFolly! From the info you sent, I'd say Black Swallowtail is a winner. :)

I'm also relieved to see that the half-silk half-caterpillar look it has going on seems to be normal and that I didn't interrupt its creation of a cocoon.

I've never actually seen one of these butterflies around here ever. The most I ever see is the occasional yellow butterfly or monarch, and those are a rare sight where I live. According to that site, they like to lay eggs on parsley and if that's true, this one sure crawled a long way before creating a cocoon. Where I found it is pretty far away from the parsley in the yard.

I'm wondering now if this would be considered a "late summer" butterfly and if I'll need to keep it over the winter. Should I attempt to suspend it from a branch in its jar or will it be able to get out of its cocoon if it's laying on a handful of grass?

Also, thanks to larry gene for identification of the furry caterpillars. Those are definitely the ones I occasionally see in the backyard in the fall (for some reason, they really seem to like being in the sand too).

Hi there--Congratulations on your swallowtail! Since the chrysalis is green, it will most likely emerge this summer. Swallowtail chrysalises need to hang from their harnesses a certain way for the butterfly to emerge correctly. I think people leave fallen swallowtail chrysalises on their sides so the butterfly can climb up and hang from something to dry its wings properly.

Take care!

I do believe my cocoon is in the home stretch now, for when I woke up and checked on it today, it changed from green to transparent. I can easily see black wings with orange dots underneath. Yay! It's not dead! In fact, it was wagging around a lot today.

Hopefully this means within the next few hours, I will have a butterfly. Will show pics if I can get decent shots. Right now, I've got the cocoon secured to a stick with dental floss, suspended from a hole in the jar lid. Also, there's a little nest of grass and leaves on the bottom of the jar.

Well what do you know? Today I changed my cocoon's grass/leaves and removed it from its stick...and added a couple sticks to the jar just in case. Imagine my surprise about a half hour later, finding the butterfly having emerged!

The only bad thing was it had major trouble finding a stick, and when I found it, it was flailing around on its back. I immediately took it outside, gently removed it from the jar, tossed out the grass, and let it latch onto the lid to hang upside down in hopes its wings would unfold.

Alas, the damage has been done. As you can see from the photo, its wings ended up drying all screwy. I don't think it's going to be able to fly, though it tried pretty hard to do so. :(

Thanks again for everyone's great advice.

awww poor thing!