Papilio multicaudata [pusillus]

Two-tailed Swallowtail

Populations of this swallowtail were assigned to the new subspecies pusillus in the Systematics publication in 1998. But research by Michael Fisher in a 2012 book on Colorado butterflies called this into question, and James Scott in 2014 argued Fisher was right, and that smaller pusillus was in fact a form and not a subspecies. The idea is that the "form" is the result of a smaller pupa due to larvae that simply aren't feeding as well as the larger populations. At any rate, I've seen multicaudata flying in Tehachapi Mountain Park, but have only been able to get photos in Arizona.

This species was described as Papilio daunus by Boisduval in 1836; however, in an article in 1884 (Papilio, volume 4, pp.103-104), W.F. Kirby of the British Museum discussed an unpublished volume from 1833 By Titian Peale called Lepidoptera Americana, which had a plate illustrating this swallowtail. Kirby referred to text on that plate identifying the butterfly thusly: "P. Multicaudata (=P. Daunus, Boisd.)". That name thus preceeded daunus by three years, but Peale cannot be the author because his work was unpublished. On the other hand, Boisduval had assigned a name already used by Kramer in 1777! With Papilio daunus unavailable, P. multicaudata became the replacement name.*

* See the discussion (pp.692-3) in George Austin and John Emmel, "A Review of Papilio multicaudatus Kirby (Lepidoptera: Papilionidae)," Systematics of Western North American Butterflies, 1998, pp. 691-700.