Drunella grandis and doddsi are large, olive green to brown mayflies commonly known as the western green drake. The species is famous on trout rivers in western North America for its prolific hatches in faster, rocky water. During the larval stage, western green drakes thrive in the well-oxygenated water of medium to fast riffles and current seams. These crawling mayflies require lots of rocky structure, debris, and vegetation to remain comfortable in their environment. The western green drake follows the life stages of a typical mayfly life cycle and hatches during the summer months of June and July with often quite intense emergences.
There is a species of mayfly found in the rivers and streams of the northeastern United States that also bears the name “green drake.” These eastern green drakes (Ephemera guttulata) are relatively large burrowing nymphs that are similar in color to the western green drake, but display a lighter tan or white abdomen. Eastern green drake activity has gained a reputation in some eastern fishing circles as an “epic hatch” but this prolific emergence is highly localized, rendering the species an important one, but not an integral one to an eastern fly angler’s overall success. The eastern green drake dun molts to the famous coffin fly spinner, a beautiful mayfly with dark, patterned wings and a bright white body.