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.

 
 










