Slide the black slotted tungsten bead onto the jig hook, seat behind the eye. Add 8-12 wraps of lead wire behind the bead and cover with dark-brown thread; keep the underbody thin.
At the bend, tie in two barred yellow Sexi Floss strands splayed as the forked tails.
Tie in the coffee/black variegated stonefly chenille at the tail.
Wind the thread forward and, as you build the body, tie in pairs of barred yellow Sexi Floss legs at the mid-point and again toward the front (one pair each side per station). The rubber legs are the whole point (a jigged Pat's Rubber Legs / Girdle Bug).
Wrap the chenille forward through/around the leg stations to the bead, tie off.
At the head, tie in two barred yellow Sexi Floss strands pointing forward as antennae, whip finish behind the bead.
Keep the body slim. A thin Pat's sinks and drifts better.