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Large macro photograph of a natural green Cheumatopsyche caddis larva with dark plated thorax, brown head, six legs, and exposed soft abdomenRepresentative photo · one form in this family

Fly family · guide 58

Caddis Larva Patterns

A bottom-stage guide separating exposed net-spinning larvae from portable-case builders without calling every green caddis larva a free-living rockworm.

Size range
Species and instar vary; sample or use a trusted local report before choosing hook size
Common colors
green or cream exposed abdomen, brown or black head and thoracic plates, locally matched case material
Imitates
free-living caddis larva, net-spinning caddis larva, cased caddis larva
How to recognize it

Caddis larvae have a hardened head and three pairs of thoracic legs but a softer segmented abdomen. Some remain exposed while using fixed silk capture nets; many others live in portable cases made from plant material, sand, or other local material. Larvae are not pupae, and Cheumatopsyche net-spinners are not Rhyacophila green rockworms simply because both may be exposed.

Large macro photograph of a natural green Cheumatopsyche caddis larva with dark plated thorax, brown head, six legs, and exposed soft abdomen
Representative photo · one form in this family

Cheumatopsyche Net-Spinner Larva

Natural Cheumatopsyche larva—not an artificial fly, green rockworm, or Rhyacophila. Although the source filename says “freeliving,” the identified genus is a Hydropsychidae net-spinner; use this photo for one exposed net-building larval form and verify local family, size, and color.

View
larval-form comparison — source-identified Cheumatopsyche net-spinning caddis larva
Color shown
green soft abdomen with a dark brown plated thorax and head
Look for
The exposed larva makes the soft green abdomen, three hardened thoracic plates, dark head, six legs, and hooked rear end visible without a portable case.
Open full-size photo ↗

On the water

Choose the right version.

Use these tips as a starting point. The river, depth, insects, and fish behavior still decide the final presentation.

01

Why it works

  • A caddis-larva imitation can present a compact head-and-thorax with a softer segmented abdomen in the bottom layer where larvae live before pupation.
  • Exposed net-spinners and portable-case builders create materially different profiles: one shows the abdomen and plates, while the other is dominated by its case with only the front of the larva visible.
  • The natural photographs make that decision visible while preserving the central accuracy limit: larval form, species, color, case material, and availability must be verified locally before selecting the artificial.
02

When to use it

  • Before a caddis emergence or between adult events when a current report, kick sample, seine, or stream inspection supports larval activity in the bottom layer.
  • Use an exposed-larva approach where net-spinning or genuinely free-living forms are plausible; use a cased profile only when local cases and case-building larvae are present.
  • Do not infer a current larval drift from an adult hatch name alone, and do not transfer Dicosmoecus size or Cheumatopsyche green into every watershed.
03

How to fish it

  • Dead-drift the exact larva imitation near the active bottom lane with only enough rig weight to reach depth while preserving a compact natural profile.
  • For an exposed net-spinner, use a controlled drift that can suggest a dislodged larva; for a case-builder, keep the presentation bottom-oriented and match the local case silhouette rather than adding generic bright color.
  • Move to a separately named pupa or emerger only when the insects and fish shift upward. A lift or swing does not turn a larva pattern into a pupa.
04

Mistakes to avoid

  • Calling the source-named Cheumatopsyche photo a Rhyacophila or universal green rockworm.
  • Using one portable stick case for every cased-caddis family, size, and stream.
  • Calling a curved pupa or winged emerger a caddis larva.

Make the choice

Choose the form before the color.

A family name is only a starting point. Use the waterline, construction, and observed food to narrow it to the form that fits the river.

  1. Use the Cheumatopsyche photograph for one exposed Hydropsychidae net-spinner: green soft abdomen, dark head, hardened thoracic plates, six legs, and rear hooks. The filename's “freeliving” wording does not make it a Rhyacophila green rockworm.
  2. Use the unidentified cased larva to recognize the portable-case relationship and visible front anatomy; the source does not support a genus, species, universal case material, or exact fly recipe.
  3. Use Dicosmoecus gilvipes for one large named case-maker with a long mixed plant-material case. It adds scale and case variation but is not the identity of every October Caddis or every river's cased larva.
  4. Choose the fishable artificial by exact name, larval form, size, color, case treatment, and ballast. Those tied patterns remain unpictured until exact licensed photography passes review.

Common variations

Small changes can make a different fly.

Three verified, non-AI natural-larva photographs compare a source-identified Cheumatopsyche net-spinner, an unidentified portable-case builder, and a source-identified Dicosmoecus gilvipes large case-maker. No artificial larva, pupa, local species, current drift, or universal green-caddis recipe is visually claimed.

Natural Cheumatopsyche net-spinner

A source-identified exposed larva showing the soft abdomen, dark head, hardened thoracic plates, six legs, and rear hooks of one Hydropsychidae form.
Colors shown
green abdomen, dark brown head and thorax
Weighting
Natural larva reference; artificial ballast must be chosen separately for the current and depth.

Natural unidentified cased caddis larva

A family-level portable-case reference showing the larval head and legs extending from a long plant-material case.
Colors shown
olive-brown larva, dark plant-material case
Weighting
Natural larva and case reference; no artificial hook or weight is implied.

Natural Dicosmoecus gilvipes case-maker

A named large case-building larva with a dark head and a long case assembled from sticks and plant fragments.
Colors shown
dark brown head, brown plant case
Weighting
Natural larva and case reference; no artificial October Caddis recipe or ballast is implied.

Related patterns

Caddis Patterns by Stage ↗Caddis Pupa Patterns ↗October Caddis Patterns ↗LaFontaine Sparkle Pupa ↗Gold-Ribbed Hare's Ear Nymph ↗

How this guide was checked

Fly information and photo sources.

Guide checked on 2026-07-13. Every image has its own source and usage record. Natural insects and hand-tied flies can vary in shape and proportion.

Pattern sources

Orvis NewsHow to Fish Caddis-Pupa Flies↗Orvis NewsThe American Grannom Is a Springtime Gem↗BugGuide / Iowa State UniversityOrder Trichoptera — Caddisflies↗

Image credits