MATERIALS:

Hook  -  Size 8 to 16 long shank
Thread  - To suit body
Tail  - Squirrel tail, feather barbules or substitute
Rib -  Fine copper wire
Weight  - Bead Head or Cone Head
Additional Weight - Lead or copper wire if required
Body & thorax  - Dubbing or peacock herl

Gills - Filoplume (optional)
Legs  - Slightly oversize hackle barbules
Wing casing - Rubber shrimp back, raffia or feather slips

A) Most beads have a large opening at one end and a smaller opening at the other. Slide a bead over the point of the hook small opening first and position it behind the eye of the hook. Wind the thread in touching turns to the bend of the hook.
B) Tie in a tail equal 1/2 to 2/3 the length of the hook shank. Resist the temptation to make the tail too bulky and too long. Tie in a length of copper wire.
C) Dub on a body starting at almost nothing and gradually increasing in width along the back half of the fly. Wind the copper wire along the body of the fly forming 5 or 6 segments. Tie the copper wire off at the half way point and trim the excess copper wire.
D) Take a small section of filoplume of a complementary colour and tie a little tuft in on each side of the fly to represent the gills. (Filoplume are sometimes called "aftershaft" and are the fluffy feather barbules that look like marabou and are found at the base of many feathers). The tips of the gills should extend out toward the back of the fly at an angle of around 45 degrees and be about half as long as the body of the fly. Tie in the back material directly in front of the body and the gills.
E) Hold the back material and the gills out of the way and dub on the rear half of the thorax making it a little thicker than the thickest part of the body. Select a small section of hackle fibres and tie them in on each side of the fly to represent the legs. The tips of the legs should extend out toward the back of the fly at an angle of around 45 degrees and be about half as long as the body.  When you look at the fly from above the gills and the legs should all be in proportion to each other.
F) Now apply some dubbing in front of  the legs to complete the bulk of the thorax. Take a little of the dubbing over the area where the legs are tied in so as to hold them a little flatter along the side of the fly. Remember that the finished thorax should be thicker than the thick part of the body. Pull the back material over the top of the fly and whilst holding it tight and in place tie it off just behind the bead. Trim the excess back material Build up a collar of thread directly behind the bead that is a thick as the thorax. If you tie this tightly you will feel wraps of thread being pulled into the wide opening of the bead and locking it into position. Whip finish behind the bead, trim the thread and varnish the collar and the bead. If you don't varnish the bead it will tarnish quite quickly.