This is probably the most popular fly designed by Sierra Flyfisher, Ralph Cutter, and introduced to the public in 1981. The E/C Caddis is an emergent/cripple caddis pattern developed for the large caddis hatches that frequent the Truckee River. At first, he tried to utilize a palmered body similar to the Elk Hair Caddis but noticed that the sillouette underwater was not similar to the naturals since the fly rode too high on the surface film. Ralph switched to a parachute wrap and utilized the Elk Hair wing as the wingpost.
In episode 19 of the Reno Fly Shop Podcast Ralph Cutter explains how and why he came up with the E/C Caddis to chase difficult to catch Truckee River trout. And how the patterns effectiveness has translated into success on other western waters.