The pattern given in his book is:
Hook - Longshank 10 to 14
Silk - Fawn
Rib - Domestic Cotton, fawn coloured
Tail and Abdomen - Between 6 and 12 fibres from the hen pheasant tail, depending on hook size. Tips form tails, the rest forms the abdomen.
Thorax - Creamy beige fur blend
Thorax Case and Legs - Hen pheasant tail,tied in with tips pointing to the rear, then brought over the thorax to form legs. Roughly divide the tips to slope back on each side of the thorax, then tie down and whip finish. A standard technique on many of my nymphs.
Olive Fraser Nymph
A very handy alternative: the addition of olive mole thorax, and a green cotton rib seems to change the whole body colour. Otherwise as above.
Please see my post
Gordon Fraser - Blended Fur for details of the blended fur.