From Fling and Puterbaugh The Basis Manual of Fly-Tying where the focus is on imitating nature

Simple Caddis Larva

Hook: #12 – 13 wet (here #16 scud/emerger)
Thread: olive (or desired color)
Rib: fine or medium copper
Body: wool to match thread color (here Crewel yarn in light olive)
Thorax: Peacock herl


Lay down thread base

Tie in wire rib


Tie in wool for body; touching wraps forward to thorax; tie off

Spiral wrap rib over body (optional to counter wrap); tie off

. .

Tie in Peacock herl behind eye; optional to create a herl rope; touching wraps to eye; tie off

Whip finish; head cement