Yellow Sally
Unusually for a stonefly, this one wants MIDDAY SUN in high summer — bright and hot, when conventional wisdom says go home. Sparse until late June and then steady through the warm part of the day. And as with every stonefly, the nymph crawls out to emerge, so it is the egg-laying female returning to the water that you are actually imitating, not a hatch.
- ScandinaviaCommon
- British IslesCommon
- North America — WestCommon
- North America — EastCommon
- Continental EuropeOccasional
- Atlantic fringeOccasional
- The AlpsOccasional
- East AsiaScarce
- IberiaScarce
Isoperla is a genus of Palaearctic and Nearctic stoneflies (family Perlodidae, the "yellow sallies"), commonly called stripetails or springflies, distributed across temperate regions of the Northern Hemisphere. Genuinely Holarctic — well represented across both Europe and North America — but absent from the Southern Hemisphere, where entirely different stonefly families (Gripopterygidae, Notonemouridae, Austroperlidae) fill the equivalent ecological niche. The photographed specimens here are Isoperla grammatica, the common European Yellow Sally; this trigger already models it alongside Chloroperla torrentium (a separate genus) for the loch-shoreline signal.