Lower Deschutes River, Oregon. May 7, 2018
Lower Deschutes River, Oregon. May 7, 2018
Oregon State University collection
Comments. This is the Oregon state butterfly. Pyle treats it as a separate species but some consider it a subspecies of either the Old World or Baird's Swallowtail.
Similar species. The Oregon Swallowtail has a) a black spot touching the edge of the orange-red spot at the the tail and b) a yellow abdomen with thin black stipes on the top and sides of the abdomen. The Anise Swallowtail is very similar but has a) a black spot in center of the orange-red spot and b) a black abdomen with narrow yellow side-stripes.