Bead a Daiichi 1760 with a gold bead and lay a base of red thread. This is a larva pattern, so do not build a taper. Bloodworms are the same width end to end.
Tie 0.1mm chartreuse wire in alongside the shank, then Flashabou at the rear.
Cut the red thread away and bring in olive thread. Two threads is deliberate: the red is the underlayer that has to show through.
Wrap the Flashabou forward in touching turns. You will see the red bleeding through as you go, and that green-over-red is exactly the point. GNR stands for green and red.
Tie the Flashabou off and counter-wrap the chartreuse wire in open segments.
Tie the wire off at the front, helicopter it out and whip finish.
Coat with your favourite glue or resin. The coat is what makes the red bleed through most strongly.