I found a black swallowtail laying eggs on my dill but they will also lay on parsley, carrot, milkweed, and fennel. The eggs are round, and are about the size of the head of a pin and are a greenish yellow color. They gradually change color from a greenish yellow to a brownish green then they hatch. They look a little bit like bird poop. I thought it was wired to have such a defense but as they grow they start to turn bright green. When they feel threatened they stick out there horn like antenna.
There chrysalis is bright green with yellow and lime green markings. But before it makes a chrysalis it makes a thread like silk to hang on to a leaf or stem. Then it gets stiff and starts to make its chrysalis. After 2-3 weeks it is finely a black swallowtail.
I have found the adult butterflies prefer butterfly bush, zinnia, and cosmos in my flower garden. I found them very fun to watch. Now I watch the butterfly’s and think what a amazing creation.