This is a traditional pattern that was first tied by James Wright for Canon William Greenwell in 1854 and has been a successful pattern since that time. It is a general imitation of olives and can be used from Spring to Autumn, due to the wide hatch period of the natural fly. On stillwater, it is a good imitation of the lake olive and pond olive. It can also be used on running water.
This is the dry version of this very popular fly (there is a nymph, wet version and a spider version) and is tied in the style of the original without a tail.