Our hatchlings are now around one week old. They are technically "first instars," which means they have not yet molted. According to Monarch Watch, they will go through five instar stages before they pupate.
You can also see the beginnings of their tentacles at both ends. As the caterpillars get larger, the tentacles will become dramatic, and look like antennae. In fact, the caterpillars have antennae, but they are extremely small, and located on either side of their mouths. At Archie's Garden, we don't (yet) have the means of photographing anything so small, but there's a good diagram, also at Monarch Watch.
Come visit again soon, and we'll keep updating this page with the latest goings-on from Archie's Garden!