I had thought that what you see above (and what the Tvetens pictured) was not a Giant Swallowtail, but a Thoas Swallowtail. The reasons for my original conclusion are described below. But I am assured that this, too, is a P. cresphontes.

Back.

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The Giant Swallowtail has a dorsal side that is noticeably different from the dorsal wing of this specimen. The USGS webpage includes an image of the Thoas Swallowtail. See here to compare the upper forewings of this butterfly with their Thoas. See also Nearctica.com, that has a page contrasting the Giant Swallowtail with the Thoas Swallowtail.

Nearctica.com has a page that shows geographical locations at which the Thoas Swallowtail has been observed. Note that the easternmost county in Texas seems to be Trinity County, just 10 miles south of this location.

May 6, 2006