My Fish Finder was created on the mainstream of the Au Sable in Michigan, http://www.flyanglersonline.com/flyt...w/2198fotw.php and was intended to represent a life form, not a specific bug. However, if you really watch it and fish it you will see that the fish take it for either a mayfly or a caddis - and in my opinion prefer it as a caddis especially since you can skate it across the surface. It is truly a fun fly to fish...and isn't that the idea?