Waterlands
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.

Hatching NowPale Morning DunGreen DrakeTricoSulphurSmall Western Red QuillFlavGray DrakeCallibaetisSpotted SedgeGolden StoneYellow SallyBrown DrakePink LadyTerrestrialsScuds & Sowbugs
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Mayfly
Hatching Now

Flav

Drunella flavilinea

The small western green drake. Flavs pick up right where the big drakes leave off — same olive-green look, two sizes smaller, and a longer, more dependable emergence.

Order
Mayfly
Family
Ephemerellidae
Genus
Drunella
Hook
#14-16
Season · Peak Late Jun-Jul evenings
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Flav
Emergence Triggers
Water Temp
54–62°F
Flow
Post-runoff, stable
Light
Evenings, cloudy afternoons
Water Type
Weedy runs, smooth currents
Lifecycle
How Trout Eat It — Stage by Stage
1
Nymph
Jun-Jul

Robust crawler nymphs get active in the evenings — an olive nymph fished shallow near weed edges.

Match It
Olive Hare's Ear#14-16
$2.75
Poxyback Flav#14
$3.25
2
Emerger
Hatch onset

Like all Drunella, flavs emerge slowly and get stuck often — cripples draw the confident eats.

Match It
Flav Cripple#14-16
$3.25
3
Dun
Evenings

Olive duns on smooth evening water — the Henry’s Fork classic after the drake circus leaves.

Match It
Flav Sparkle Dun#14-16
$3.15
Parachute Flav#14
$3.25
4
Spinner
Dusk

Olive-bodied spinners over riffle tailouts at dark.

Match It
Flav Spinner#14-16
$2.95
Cross-Reference
Where This Bug Matters
Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records
USGS Real-time Data · Free to Start · No Credit Card