Swallowtail butterfly tiger swallowtail), Y-linkage determines whether the females are either wild-type (yellow and black) or melanic (dark melanin replaces the yellow background). This genetic difference stems from the fact that melanism is controlled by a single gene, which controls the level of dopamine in the organism. The enzyme BAS, which assists dopamine in producing the yellow pigmentation, normally found on the wings' background, is suppressed. Without the pigmentation, the butterfly appears mostly black (the melanic form) and is a Batesian mimic of "Battus philenor", the pipevine swallowtail. There are also "Papilio glaucus" that are not wholly black; several possess an intermediate
Swallowtail (flag) Swallowtail (flag) In flag terminology, a swallowtail is either The name comes from the forked tail that is a common feature of the swallow species of birds. Common in Scandinavia, this swallowtail flag contains a vertical section in the centre of the fly. Also common in the Nordic countries, the swallowtail flag contains a third tail (the "tongue") between the other two tails. This is the shape of the United States' state flag of Ohio, as well as some burgees, private signals and pennants of the International Code of Signals (ICS) use a triangular swallowtail shape. A guidon is the