Giant Swallowtail

I think the Giant Swallowtail is spectacular, but they were so common in Texas that people on the NABA trip ignored them in favor of small buff colored skippers that might be something rare. The caterpillars eat citrus, and fruit growers call them "Orange Dogs" because of the damage they cause to the foliage. I suppose this could be a Thoas Swallowtail, but I doubt it.