Nightly frosts brush the garden, but botanical energy continues to surge. Carrots, lettuces, and chard are all thriving in the cool sunshine. Black swallowtail butterflies have tapped this energy, laying eggs on the carrot leaves. The caterpillars fall into an inert stupor during the cold nights, but turn into animated single-minded leaf-munchers when the sun touches their skin. They are all in their last stage of molt. The next step will be transformation into overwintering pupae.
For reasons unknown to me, Linnaeus named many swallowtails for prominent figures in Homeric/Greek poems. The black swallowtail is named (polyxenes) for Polyxena, the daughter of Priam, King of Troy. She does not appear in the Iliad but other accounts tell that her death marked the end of the Trojan War. The connection between these tales and North American butterflies seems tenuous, at best. But Linnaeus invented the rules of nomenclature, so he could do as he pleased.
Our caterpillars need not fear Achilles and, with luck, the birds will not find them.