Black Tiger . . .

. . . Swallowtail butterfly:

I know I've mentioned this before, but the Eastern Tiger Swallowtail butterfly has two different color patterns, the yellow and black form, which both males and females partake of, and the mostly melanistic (black) form, which only some females take on. This girl visited the Butterfly Weed for most of the day.

There are multiple black and blue butterflies, including the Spicebush Swallowtail, the Black Swallowtail, the Pipevine Swallowtail, and the Red Spotted Purple (the only one not a swallowtail). You can easily see that this one is an Eastern Tiger from the brownish color underneath, with the stripes showing through, the lack of yellow markings on the body, and the pattern of yellow-orange markings on the underside of the hind wings. Note the pollen.

It is thought that the other "black and blue" butterflies are mimics of the Pipevine Swallowtail, which is toxic from it's caterpillars eating Pipevine (the same way Monarchs are from eating Milkweed). All the other "black and blue" butterflies are the same color for both sexes (although there are some sex differences in the patterns), and only the Tiger Swallowtail has the female taking two different patterns.  It's thought that in areas where Pipevine Swallowtails are abundant, more Eastern Tiger Swallowtail females are black. Around here, I think well less than half the female tigers are black. Pipevines are pretty sparse too, unless they hide somewhere else then where I look.