Female Sweltsa (Sallflies) Stonefly AdultView 8 PicturesThese stoneflies--abundant during midday--seemed at first to be flying around with plain yellow bodies, but on closer inspection turn out to have striking, fiery red abdomens. This one keys out to albertensis, gaufini, or lambda, but the key (Baumann et al 1977) doesn't include all current species.