There are many variants of this fly , here are a few that I use (The Olive and Fluo Pink Tail being my favourites).
The following pattern is a variant of the Dawson's Olive. This version uses a few different materials to the original.
The Dawson's Olive pictured is tied with Straggle Fritz rather than the traditional Chenille Body and uses a thorax of Olive Ostrich Herl to give a bit more pulsating movement at the head.
The Original Dawson's Olive pattern was as follows :-
Hook - Size 8-12 Longshank
Thread - Brown
Tail - Golden Yellow Marabou
Body - Olive Chenille
Rib - Oval Gold Tinsel
Wing - Olive Marabou
Hackle - DYed Blur Guinea Fowl
STEP 1 : Insert a gold bead onto the hookshank (3.8mm shown on a size 8 L/S hook). Insert the hook into ther vice and wind the olive thread down the hookshank to a position opposite the barb.
STEP 2 : Take a bunch of olive marabou, catch in and secure along the hookshank with thread . The marabou needs to be about the same length as the hook shank.
TIP: When preparing the marabou, place the marabou tips in your left hand between index finger and thumb and with the right hand move your thumb and index finger nails down the marabou stripping the webby marabou bulk off the stems. This will result in a slimmer body when tied in.
STEP 3 : Now catch in a length of olive straggle fritz and some medium oval gold tinsel. Return the thread to a position just short of the eye.
STEP 4 : Wind the straggle fritz up the hookshank, with each turn wet your fingers and brush the fibres backwards before the next wind. This should prevent the fibres from being trapped under the windings. Secure with thread just before the eye and trim waste.
STEP 5 : The straggle fritz I use has very long fibres and I trim them with scissors to suit the fly. Grip the fibres between the index finger and thumb of your left hand and trim with scissors. Repeat this for the bottom and both sides until you have uniform fibres around the whole fly.
STEP 6 : Now wind the tinsel around the body to create a rib, make sure that the majority of straggle fritz fibres aren't trapped.
TIP: When winding wire or tinsel around fibres and these can be fritz or hackle fibres, move the tinsel left and right horizontally in wide strokes., This tends to release the fibres that would have otherwise been trapped..
STEP 7 : If too many fibres are trapped use a dubbing needle or your nails to pull some of the fibres out from under the tinsel. Tie off the tinsel and trim waste.
STEP 8 : Take a bunch of marabou for the wing. The length of the wing when flat should run from back of the gold bead to just beyond the tail. Tie the marabou wing in, secure and trim any waste.
STEP 9: Catch in a piece of olive krystal flash at each side of the wing. Secure and trim waste.
STEP 10 : Now reverse the fly so that the hookpoint points upwards. Take a few blue hackle fibres and tie in just behind the bead. This will create a beard for the fly.
STEP 11 : Position the fly the correct way up in the vice with the thread now at the start of the thorax.
STEP 12: Tie an olive ostrich herl in at the start of the thorax position tip first. Wind the herl in tight turns up to the gold bead. Secure the herl, tie off and trim any waste.
Final: The finished fly.