Hook-3X long 2X heavy streamer hook-size 6
Lead or Brass dumbell eyes-black-9/64
Thread-black or clear mono-6/0 black works perfect
Tail-black zonker strip
Rib-wire or mono
Body-dubbing-black or black/brown mix-wrap up to behind eyes
Small saddle feather-black
Silicone rubber legs-black-one on each side
Head-Same dubbing as body
Pinchers-silicone rubber legs
When constructing this pattern, keep in mind that hellgrammites are not usually solid black. Depending on the water you fish, these aquatic insects can have mixes of blacks and browns to be effectively hidden under rocks and evade capture from hungry predators. Pay attention to the hellgrammites in your local waters and mix your dubbing accordingly to match their coloration. In my local smallmouth bass streams, most hellgrammites are black with hints of dark brown. As a result, I mix my dubbing to ensure I can reflect their true colors. When you put in the first set of silicone rubber legs, make sure that they are no longer than the inside of the hook gap. The rubber legs on the body and the head not only break up the pattern but provide the defining pinchers for the hellgrammite. The thread head at the front can be coated with black finger nail polish, black fabric paint, head cement, or super glue. The brass or lead eyes provide a small amount of weight to ensure the fly can get down and keeps the hook point riding up when being fished. This will cut down on snags.
This fly can be fished a couple different ways. The primary method I use is under an indicator. Riffles and runs will be main areas of focus. Mending does not need to be perfect as aggressive mends will impart action on the fly and can stimulate aggressive strikes from hungry bass. If you are fishing from the bank and want to try a different approach, try casting this fly without an indicator and slowly, but steadily retrieving the fly towards the shore. This can be very effective in hellgrammite rich waters where they swim towards the shore and hatch. Do not forget to fish the hellgrammite! Some of my big fish early in the year are always taken on this important insect. If you fish it enough, you will catch other fish including carp. Good luck and give this fly a try!