Northern Prairie Wildlife Research Center
Wingspan 3.4 cm. The wings are green with a single white line. This geometrid is widely distributed in western North America. Moths fly in midsummer. Caterpillars feed on the foliage of flowering trees and shrubs such as ocean spray (Holodiscus discolor) and bitterbrush (Purshia tridentata).
Similar species: a Rocky Mountain population of a similarly appearing species has been treated as Chlorosea nevadensis; C. banksaria may be distinguished from other green geometers by their large size and the single white line.