River Intelligence · Entomology

Read the Water. Match the Hatch.

Every river has an entomological fingerprint — the bugs it grows, when they hatch, and how trout eat them. Learn the bugs, cross-reference live flows, and fill your box before you go.

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Encyclopedia Hatch Calendar River Fingerprints Match the Hatch Bug School

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Caddisfly

Little Black Caddis

Brachycentrus americanus

A small dark grannom that opens the caddis season on many freestone and tailwater reaches. Easy to mistake for the Mother’s Day Caddis; it runs a size or two smaller and a touch later.

Order

Caddisfly

Family

Brachycentridae

Genus

Brachycentrus

Hook

#16-18

Season · Peak Apr-May

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

Little Black Caddis

Emergence Triggers

Water Temp

48–56°F

Flow

Spring flows before the runoff peak

Light

Midday to afternoon

Water Type

Riffles and gravel runs

Lifecycle

How Trout Eat It — Stage by Stage

Larva

Year-round

Cased larvae on gravel — a small cased or rock-worm imitation covers them.

Match It

Green Rock Worm#16

$2.75

Pupa

Hatch onset

Dead-drift or swing a small dark pupa through riffles as adults begin to show.

Match It

Sparkle Pupa#16-18

$2.95

Adult

Afternoon

Dark adults cluster along banks; egg-laying females draw splashy rises.

Match It

Elk Hair Caddis#16-18

$2.95

X-Caddis#16

$3.15

Cross-Reference

Where This Bug Matters

Bighorn River

≋ Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records

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