Ornythion Swallowtail (Papilio ornythion)
This US rarity found only from southern Texas to southern New Mexico is similar to the Giant Swallowtail, but note that the yellow bands in the forewings do not form an "X". Also, note that the tails lack yellow.
Chihuahua Woods RR tracks, Hidalgo Co., TX 18 Oct 04
Created on ... May 5, 2007 | Updated ... May 5, 2007 | firstname.lastname@example.org