The North American cicada Okanagana viridis Davis has been little reported in the literature for nearly 80 yr. We provide the first notes on the song and ecology of this elusive species, and we update its known range. O. viridis is unusual in a large genus of 60 otherwise arid- or cold-adapted, mostly western U.S. species, in that it is found in the temperate deciduous southern forests of Arkansas, Louisiana, Mississippi, Tennessee, and Texas. It is the only almost solid bright green Okanagana Distant, and it calls from high in trees during daylight hours and occasionally at dusk, during the summer months. The song is a thin, dull, steady whine ≈30 s in duration; it is composed of irregular doublet or triplet pulses given at a mean rate of 127/s, with a mean peak sound frequency of 9.27 kHz. O. viridis is uncommon in collections, and it appears restricted to remaining small forest patches near lowland river deltas.