Slide the 3.8mm matt black tungsten bead to the eye and wind several turns of 0.1mm lead wire on the shank behind it; its only job is to keep the bead secure. Start the thread, bind the lead down, and add a drop of glue over bead and lead.
Run the thread to the bend and form a dubbing loop there: fold the thread over your finger, bind it in, then advance the thread to the front.
Load the loop with a mix of deer hair and olive Mad Rabbit dubbing (a spiky dubbing works best). It should look like a bird's nest. Spin the loop tight with a rotor-style dubbing tool, then brush the fibres out so it is buggy.
Wind the spun loop forward in touching turns all the way to the bead. Secure and bind off.
Trim the body hard with scissors on all sides and underneath to a slim, compact case: a real cased caddis is compact, and a slim body sinks fast. Brush it out on all sides, then trim again.
Legs: split the thread with a dubbing needle and lay a bunch of olive roe deer hair across the split. Push the hair in so little sticks out the far side, pin the thread with a finger, and spin the bobbin until the hair is properly locked in the thread.
Wrap the spun hair close behind the bead, pulling the fibres backward as you go, then take a few tight turns against the bead and whip finish.
Snip the deer hair off the sides and top so it only projects downward. Press each bunch over a dubbing needle with your finger to kink it into leg shapes, then trim the excess short and compact. Brush the body once more to keep it buggy.