Today, two of those caterpillars (or that one and a friend) had anchored themsevles to my house to become butterflies. My friend was with me and together we remembered what they are: they are swallowtails.
I was on a website about swallowtail trying to figure out exactly what kind I have growing and it casually mentioned the importance of swallowtails in Mexican folklore and even provided a handy link for me to learn more. I love it when people are organized.
From that site (emphasis mine):
Many of the indigenous peoples of the New World hold butterflies in a special place in their culture. However, nowhere is the presence of butterfly motifs more prevalent than amongst the Aztec, Mixtec, Teotihuacan, Toltec, and Zapotec cultures of highland Mexico. For example, butterflies figured prominently in the life of the Aztecs, who dominated the Central Valley of Mexico between 1300 and 1523. At least two of their many deities were personifications of lepidoptera Xochiquetzal ("precious flower") and Itzpapalotl ("obsidian butterfly). The former closely resembles a Two-tailed Swallowtail while the latter is identified with the large silk moth, Rothschildia orizaba. Both deities were female and had many attributes.
For example, Xochiquetzal was regarded as a mother goddess, goddess of love, goddess of flowers, as patron of all fine arts, as the symbol of beauty, as the symbol of fire, as the symbol of the spirits of the dead, as the patron of domestic laborers, and as the patron of warriors killed in battle. In fact, this goddess supposedly followed young warriors into battle and at their moment of death, coupled with them, clutching a butterfly between her lips!
Itzpapalotl was a mother goddess, goddess of obsidian and knives, of human sacrifice and of war, the personification of the Earth, the patron of women who died in child birth, and more. The early Spanish chronicles state than when Quetzlcoatl (perhaps the Aztec's most beloved god-king) abolished human sacrifice as a response to Spanish dictates, butterflies were burnt alive as a sacred effigy.
Of course, I know all about Itzpapalotl (why else would my web site be called Obsidian Butterfly?) But I don't think I knew that Xochiquetzal was a butterfly goddess as well. A swallowtail butterfly goddess. Who symbolizes the spirits of the dead. And in 2 days I saw 2, possibly 3, swallowtail caterpillars. I am choosing to see this as a message from my beloved dead. The caterpillars are to the west of my house, the home of the Pool of Souls, and one of my beloved dead crossed over 3 days ago.