Papilio solstitius, commonly known as the midsummer tiger swallowtail, is a species of swallowtail butterfly, in the genus Papilio. It is closely related to Papilio appalachiensis, Papilio canadensis, and Papilio glaucus.
Papilio solstitius gets its name from the Latin word solstitius, which means solstice. It gets this name because of its flight pattern, being in the midsummer, near the summer solstice.
Papilio solstitius is native to the Northeastern United States and Southern Ontario.