In second grade at Parker's school, they do a long project where they learn the life cycle of caterpillars and butterflies. They get caterpillars and watch them turn into butterflies, they collect milkweed and hatch (?) some monarch caterpillars which then turn into butterflies, they visit a butterfly festival, and they sell milkweed seeds in decorated biodegradable pots to raise money for Save the Monarchs or somesuch.
In my garden I bought and planted some dill....I don't really use dill but I read that it keeps the cucumbers company. Parker found a couple caterpillars chowing down on my dill plants and captured them. I'm not sure how a caterpillar/butterfly finds a tiny dill plant in the overplanted jungle that is my garden, but they did.

These are terrible pets in that they will only eat fresh organic herbs, but they are great pets because they eventually leave home. Hopefully in grand fashion after they've become a Swallowtail butterfly.
There are 2 of them. One day, one of them basically doubled in size. Parker named him Leader, and the smaller one Follower. We've all enjoyed watching them mill around and chow on herbs. One morning Parker was looking and looking and looking and finally said: "I can only find one." That was sort of worrisome to think he might be loose in the house somewhere, possibly hiding in my shoe. I looked and looked too, and finally found the missing guy at the very top wedged between the lid and the side. Bob later reported the one of them had been unusually active that morning, circling the top, circling the bottom. Apparently he was looking for a spot to start his chrysalis. ~NOT~ a cocoon, those are for moths I've learned.
Parker inspected him and realized it was the small guy, "IT'S FOLLOWER!" We were all surprised...my money was on Leader to be the first to change. Here's how he looked for about a day. The next day his outer skin molted off - Parker showed me this by saying "see that thing down there that looks like his head fell off? It didn't really, that's just molted skin.". Luckily she told me that before breakfast or there might have been more than molted caterpillar skin on the floor.
Now he looks sort of like a leaf. Leader made his chrysalis too, but his was lower down and it's green. It will be interesting to see if they are a different type of butterfly, or if Leader somehow made his
chrysalis green for camouflage reasons. I'll try to get some pics that taken and posted.