Hummingbird and Butterfly Gardening: DAILY BUTTERFLIES Page 62, 1 by mellielong

mellielong wrote:
He was in the mood to pose, however. As always, let me point out the yellow line parallel to the body on the underside of the wing. This is a sure-fire way to ID a Palamedes (vs. a Black ST). Other Swallowtails will not have that line.

I also can pick out the Palamedes because the yellow on the topside looks more like it was airbrushed on whereas the Black ST has more defined borders to the yellow.