When to use it
- When the local food form, size, water type, and target depth support the exact pattern or family member.
- Use the linked river report as seasonal context, then verify what is present before choosing size and weight.
Pattern family · guide 144
A small aquatic-larva family with a narrow segmented body, enlarged rear attachment disc, and compact dark head.
Black-fly larvae are slender and slightly club-shaped rather than broad like caddis larvae or oval like sowbugs. Thread, wire, dubbed, beaded, and realistic forms remain labeled.
Representative forms
A family-level comparison of Slim thread larva, Segmented wire larva, Beadhead larva; no single drawing represents the whole family.
On the water
The river, depth, insects, and fish behavior still decide the final presentation. These are reviewed starting points—not a claim about what is happening today.
Variant control
The comparison map separates materially different body profiles, weighting, hooks, or life-stage cues. It is a family guide—not one universal recipe.
Representative family forms
Black-fly larvae are slender and slightly club-shaped rather than broad like caddis larvae or oval like sowbugs. Thread, wire, dubbed, beaded, and realistic forms remain labeled.Review trail
Pattern facts were reviewed on 2026-07-12. Every image has its own rights record; photographed hand-tied flies may still vary slightly in proportion.