Illustration· After a photo by S. Rae (CC BY 2.0)Stoneflies
What it is
Stoneflies (Plecoptera) matter most on faster, well-oxygenated rivers, where nymphs — two tails, six legs, armoured — live under stones and occasionally drift, giving trout and grayling a high-calorie meal. This is the weakest-represented group in the catalogue: no fly is named or documented as a specific Irish stonefly imitation.
Life cycle
Egg
Laid in fast, well-oxygenated river water.
Nymph
Armoured, two tails, six legs; lives under stones and occasionally drifts, giving trout and grayling a high-calorie meal.
Adult
Winged and terrestrial, short-lived.
In Ireland
The Stimulator began life as an American giant-stonefly pattern, but the catalogue's own fly-detail record treats it purely as a general buoyant river searcher here, not a stonefly match — a content gap flagged for Alex. Irish-specific stonefly phenology was not located in this research pass; the biology cited is general UK/global.
Sources & how we know this (2)
- Stonefly nymph biology, importance to river trout diet
2 Guys and a River, Entomology 101 – Stoneflies · 2026-07-09 - Stimulator origin as American giant-stonefly pattern
Wikipedia, Stimulator (dry fly) · 2026-07-09
Draft reference — pending review.