Saddle-Case Caddis

Common Names: Igloo caddis
Scientific Name: genus Glossosoma

These little guys build a dome-like case from pebbles and attach it to a large rock in a riffle or a run with moderate to fast current. They are so firmly attached and protected that cased larvae are rarely found drifting in the current.

However, a larva will outgrow its shelter and leave it to build a new one. This happens often enough that uncased larvae are regularly seen--and eaten--by trout. So a creamy larva pattern dead-drifted near the bottom is a reasonable tactic in waters that are rich in saddle-case caddis.

Pupation occurs in the same water that the larvae lived in. During a hatch, dead-drift a pupa pattern near the bottom using trout indicator or tight line tactics; present the fly in riffly water or just below riffles. An unweighted pupa pattern can also be drifted near the surface, or you can present a Soft Hackle with a wet-fly swing. Another good strategy is a dry fly with a pupa pattern as a dropper or trailer; the dry fly acts as an indicator and sometimes is taken by the trout.

After the hatch, errant and unlucky adults fall onto the water, and a dry fly is the right choice. Bankwater downwind or downstream from overhanging trees is a good place to cast your dry.

Females swim or crawl underwater to lay eggs. You can fish a dry at this time, or go subsurface with a Soft Hackle or Diving Caddis pattern.

 

How to Match a Saddle-case caddis

Hatches are matched from Westfly's database of "standard" fly patterns.

Larva
Size 16-18 Hares Ear. Body: tan, green Shroud: tan, light green
Riffles, fast runs; just below these: indicator, tight line
Pupa
Size 16-18 . Body: tan, green Shroud: tan, light green
Riffles, fast runs; just below these: indicator, tight line, shallow nymph
Pupa
Size 16-18 Deep Sparkle Pupa. Body: tan, green
Riffles, fast runs; just below these: indicator, tight line
Pupa
Size 16-18 Soft Hackle. natural
Moderate to fast runs, riffles: surface swing, shallow nymph
Adult
Size 16-18 Goddard Caddis. Body: tan, olive-brown; Wing: tan, brown, gray
Bankwater near foilage: standard dry fly
Adult
Size 16-18 X Caddis, Elk Hair Caddis, Parachute Caddis. Body: tan, olive-brown; Wing: dark brown, black
Riffles, seams, backeddies below riffles: standard dry fly
Egg-layer
Size 16-18 Soft Hackle, Diving Caddis. Body: tan, olive-brown; Wing: dark brown, black
Riffles, seams, backeddies below riffles: surface swing, shallow nymph, rising nymph

 

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Characteristics

LARVA COLOR: Tan, cream, yellow with pink tinge

PUPA SIZE: 3-7 mm

PUPA COLOR: Body--Tan or green. Shroud--Tan or light green shroud

ADULT SIZE: 3-7 mm

ADULT COLOR: Wing--tan, brown, or gray wing. Body--Tan or olive-brown

OTHER CHARACTERISTICS: Larva lives under dome-shaped case made from small pepples. Body, wing, and shroud colors can vary, so it's always best to check a natural insect where you are fishing. Colors will darken when the insect is ready to lay eggs.

 

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