The Pacific and Plains Forktails have a wide distribution in Arizona and can be locally abundant. Mature males of both species are easily identified by the color of their thorax (front: black; sides: blue) and two pairs of blue dots on the front of the thorax. Separating the two species, however, requires close examination of the abdomen tip.
- Pacific Forktail: conspicuous forked dorsoapical projection on segment 10; relatively small cerci; paraproct tips straight;
- Plains Forktail: small (compared to Pacific Forktail) dorsoapical projection on segment 10; large cerci; paraprocts tips distinctly curved upward.