I mentioned with my last photo that there are two species of Tiger Swallowtail in my area. From the Massachusetts Audubon Society, "The "regular" Tiger Swallowtail is distinguished by a row of yellow spots paralleling the black border of the outer edge of the under surface of the forewing. In the Canadian Tiger Swallowtail subspecies, (P. glaucus canadensis, Rothschild & Jordan 1906), instead of the row of yellow spots, there is an unbroken yellow band." This image shows spots rather than a band on the underside of the wings. Glad you asked. :-)
