Black swallowtails (Papilio polyxenes) can easily be misidentified if you’re not paying close attention.
Black swallowtail caterpillars can be mistaken for monarch caterpillars (Danaus plexippus). They have very similar coloring. The key difference is that black swallowtail caterpillars have yellow spots, while monarch caterpillars only have stripes. Monarch caterpillars feed exclusively on milkweed plants. Black swallowtail caterpillars feed on a variety plants, but not milkweed.
Black swallowtail butterflies can be mistaken for the black morph of the eastern tiger swallowtail (Papilio glaucus). The key difference is that black swallowtails have two rows of yellow spots and eastern tiger swallowtails have only one row of yellow spots on the back of their wings. In both species, the males have very little blue on the back of their wings, while the females have more blue.
Have you seen a black swallowtail this summer?