Distinguishing characters

Oligophlebodes sigma is recognized by the following composite of characters:

Wings: Forewings unpatterned.

Male genitalia: Lateral lobe of inferior appendage sickle-shaped, oriented in the horizonal plane. X external branch rounded distally.

Similar species: Oligophlebodes sigma appears similar to O. ardis and O. minutus in respects to (1) the shape of the lateral lobes of the inferior appendage lacking interior dentitions in O. sigma, but with dentitions present in O. ardis, and (2) the shape of the lateral lobes of the inferior appendages of O. sigma oriented in the horizonal plane, but twisted ventrad in O. minutus.

Distribution

Oligophlebodes sigma has a limited distribution confined primarily to Utah and Colorado.