Build a lead-tape underbody: lay a flat layer forward, a second layer back, and a third up the middle to give weight without bulk.
Start 70-denier thread behind the eye, cover the lead underbody, and trim the tag.
Tie in a few antennae fibres at the rear so they splay off the back of the hook and secure the excess forward.
Tie in a tan (or grey) ostrich herl by its stripped tip at the rear for the body/legs.
Tie in two strands of black Krystal flash on top for the dorsal line, then a length of silver wire for the rib, both at the rear.
Wind the thread to the front, then wrap the ostrich herl forward in touching turns to a full body without crowding the eye, and tie off; wet and stroke the herl flat on top.
Pull the Krystal flash forward over the top to form a black dorsal stripe and tie it down at the front; fold the tags back and trim.
Fold a clear thin-skin strip in half, lay it on top overhanging the rear slightly, and tie it down at the front to form the shellback.
Spiral the wire rib forward over the thin skin and ostrich in five or six even segments, tie off and trim, then whip finish (over or under the thin-skin flap) and finish with a couple of half hitches.
Flatten the finished body with pliers or scissor jaws to give the broad, segmented sowbug shape.