Here is another one of my fav's both on lakes and on rivers.
Hook: TMC 2457 #10-12 OR TMC 2487 if you want the bug to float higher in the water column.
Tie in a small clear glass bead at the tail
Tie in the shell back just above the bead, I use various leather that I get from a shoe repair shop and from my wife's "surplus" belts & other such disposable like that. My fav' is a piece of "leatherette" material that I get from a sewing store. This stuff will strecth a bit in one direction but not the other. Cut the strip so that it will stretch over the body.
Body: Make a dubbing loop with Metallic thread (also from sewing store) and dub the body with olive dyed muskrat or similar material. Pick at it to get guard hairs to stick out.
Shell back: Black leatherette. Pull this over the body and tie off at the front, leave enough space to whip finish.
Legs: I use elastic thread (guess where I get this?) and unwind the wrapping. The rubber insert is the perfect size and is round. Tie the legs in about half way up the shank, secure with figure 8 then continue the body dubbing
For fun, you can use various other colors for the shell back and make all sorts of beetles and lady bugs & such, just omit thelegs or place them at the front like antennae.
Pete AKA Frenchcreek from Calgary