The tying here is for a Depth Charged Corixa, its basically a standard Plain Hackled Corixa with a large gold bead added at the thorax which allows the fly to sink very quickly. If you want the standard Corixa , the tying method is identical as below but with the gold bead removed.
STEP 1: Push a gold bead onto the hookshank and leave it positioned at the eye. Catch in the tying thread behind the bead. (Do not secure the bead into position just yet).
STEP 2 : Catch ina bunch of pheasant tail fibres and run the thread down the hookshank to a position opposite the barb. These pheasant tail fibres will eventually become the back and thorax cover.
STEP 3 : Now catch in a length of light brown thread , this will be used for the rib.
STEP 4 : Catch in a strand of white wool and return the thread up to the gold bead.
STEP 5 : Wind the wool back and forth along the hookshank, creating a tapered body. Finish the wool at the gold bead, tie off with thread and trim the wool.
STEP 6 : Wind the light brown thread up the hookshank, creating a rib as you go. Secure with the black thread at the gold bead and trim waste. Whip finish the black thread and cut away.
STEP 7 : Push the gold bead backwards into the white wool and catch in the black thread again, this time in front of the gold bead.
STEP 8 : Now catch in a bunch of grizzle hen hackle fibres.
STEP 9 : The final step is to pull the pheasant tail fibres forward over the back and gold bead and secure with thread. Trim any waste fibres, create a neat head, whip finish, trim thread and varnish.