Hook 6X long streamer hook (3-6X long), #6 (range #6-10)
Thread Black 140 denier
Materials
Acrylic yarn (head) Green (yellow in the original, brown also fine) (Two strands folded to make four)
Dry fly hackle Brown hackle (1 feather)
Dry fly hackle Grizzly hackle (1 feather)
Cactus chenille (body) Dark peacock cactus chenille (About 4 in)
Head cement Clear head cement (One drop)
How to tie it
Start black thread mid-shank and take it back to the bend of the hook, on this fly the bend end is the caterpillar's head.
Tie in two strands of four-strand acrylic yarn at the bend, then fold them back over themselves so four strands bunch up into a small bulbous head; take enough wraps to secure it and trim the excess.
Tie in a brown and a grizzly dry fly hackle together at the same point, concave sides together, with a few loose open wraps. Second-quality cape feathers are fine here. This fly is not meant to float high.
Take the thread forward to just behind the eye and tie in the dark peacock cactus chenille there, binding its core back down the shank toward the yarn head to keep the underbody even.
Wind the cactus chenille forward in touching turns to the eye to build a full body, overlapping wraps will bulk it up further if you want a fatter caterpillar, then secure with a couple of wraps and trim.
Palmer both hackles forward together in open turns to the eye, spacing them so the fly stays scruffy rather than densely hackled, then tie off and trim.
Wet your fingers, sweep all the fibres back to clear room behind the eye, whip finish and add a drop of head cement.