How to Tie a Realistic Hydropsyche Caddis Larva Fly

Fly Tying

Aug 9

This step-by-step guide shows you how to tie a super impressionistic Hydropsyche caddis larva—one of the most common and trout-eaten patterns in fast-flowing rivers.

Step-by-Step Instructions

Step 1: Weight the Hook

Place a K4A hook in your vise.
Wrap lead wire down the shank to create weight for deep sinking.
Stop about one lead-width behind the eye and break off the end.

Step 2: Start the Thread

Attach olive Power Silk thread behind the lead wraps and trim the excess.
Wrap the thread well around the bend of the hook.

Step 3: Add Tail Appendages

Pluck a small fluffy philo plume from a partridge body feather.
Strip the lower fibers and tie it in flat on the hook bend with the concave side facing down.
Trim the center stem to form a small gray "V".
Adjust the length by pulling the fibers together and trimming.

Step 4: Attach Latex for Abdomen

Cut a 3-inch strip of narrow nymph skin (latex) at an angle.
The longer angled edge is the trailing edge—tie it in just forward of the tail.
Keep thread tension high to bind it securely.

Step 5: Add Body Gills

Select 3 plumes of natural gray ostrich herl.
Tie them in as a bunch, rotated to the underside of the hook using upward tension.

Step 6: Build the Abdomen

Stretch the latex slightly and begin wrapping forward to create overlapping segments.
Segment size should taper toward the hook eye for realism.
Tie off the latex with fine spiderweb thread, secure tightly, and trim the excess.

Step 7: Ribbing and Body Gills

Use your tying thread to rib the body, following the back edge of each segment to enhance realism.
As you rib forward, trap the ostrich herl fibers underneath to form underside gills.
Ensure even spacing and tight wraps to keep the gills aligned along the body’s underside.
Trim the gill butts flush with the top of the body.

Step 8: Add Legs

Strip fibers from a golden pheasant tail using a horizontal pull for pre-curved legs.
Position the first pair: one fiber on each side of the body, adjusting direction as desired.
Secure the legs by wrapping thread into the latex groove and trimming excess.
Repeat for a second and third pair, spacing them evenly.
You should end with six legs total.

Step 9: Whip Finish and Head

Spiral thread forward, maintaining tension.
Whip finish at the eye and trim off the waist.
Create a bold but neat thread head.

Step 10: Final Touch – Coloring

Use an olive-brown marker to color the dorsal surface of the fly.
Darken the thoracic area and head with a black marker.
Apply a drop of head cement to the thread wraps for durability and a glossy finish.