[2][3][4] P. tenuicinctus is a medium-sized beetle, with adults that measure about 8.5–11.5 mm (0.3–0.5 in) long.

[9] The specific epithet refers to the pale border on the elytra, which is thinner than on other Photinus species.

[5] Beetles such as P. tenuicinctus go through four life stages: egg, larva, pupa, and adult.

[1][10] Adult male P. tenuicinctus fireflies fly 1–2 m (3–7 ft) off the ground and flash to attract the attention of females.

[11] P. tenuicinctus has only been recorded in eastern Oklahoma and northern Arkansas, in the Ozarks.