Little Green Stonefly

Other Common Names: Green stonefly, little olive stonefly
Scientific Names: genera Sweltsa, Suwallia, Alloperla

Nymphs of little green stoneflies live in plant debris in riffles and runs with moderate flow. They are seldom available to trout until mature nymphs migrate towards shore to emerge. During the migration, you can dead-drift a nymph near the bottom with some success.

The best fishing is in the evening when adult females lay their eggs on the water. A dry fly works well at this time. There's nothing tricky about the fishing--standard patterns of the appropriate size and color, presented with standard tactics in obvious places. The problem is that most fly anglers don't even know there's a hatch on. More glamorous bugs are hitting their stride at this time of year (July and August), and the little green stones are overlooked in the fading light of a long summer evening. While anglers may be unaware of their presence, trout are often keenly interested.

Characteristics

NYMPH COLOR: Dark brown

ADULT SIZE: 9-12 mm

ADULT COLOR: Wings--light green to pale yellow wing. Body--Pale yellow to light green body (greens can be fairly bright)

OTHER CHARACTERISTICS: Nymph--no external gill filaments. Adult--well-developed tails.

 

More About Little Green Stoneflies

Beyond the Big Stones by Jeff Morgan.

Click on the fly name to see the pattern. Click on the presentation to learn how to do it.

STAGE PATTERN SIZE/
COLOR
PRESENTATION WHERE
Egg-layer Parachute Hares Ear 10-16
Pale green, pale yellow
standard dry fly Riffles, seams, backeddies, below riffles
Stimulator 10-16
Pale green, pale yellow
standard dry fly Riffles, seams, backeddies, below riffles
Elk Hair Caddis 10-16
Pale green, pale yellow
standard dry fly Riffles, seams, backeddies, below riffles