Among the few published fossil records of cleptoparasitic bees, one has been assigned as an unnamed species of Coelioxys (Megachilinae: Megachilini). The putative Coelioxys was recovered from the Latah Formation (Miocene) near Juliaetta in northernwestern Idaho. Herein I provide a detailed description and figures for this specimen. While the specimen is quite likely a megachiline bee, it is not possible from the wing alone to consider this fossil as a member of the genus Coelioxys, nor of the tribe Megachilini. The fossil is considered herein as “Megachilinae species indeterminate.”