A photo of the antenna bases will show four spots. Always pale green. Orange-red on the vertex similar to O. niveus, but orange-red does extend to pronotum.
SINA: https://orthsoc.org/sina/585a.htm
Also see Walker (1962) linked from SINA.
Statewide.
Occurs at mid-levels for Tree Crickets - undergrowth, lower in trees, large bushes, etc. Walker (1962) discusses different habitat niches of Oecanthus species.