Epeorus (Caucasiron) alpestris, larva: A labrum (left half in dorsal view right half in ventral view) B incisors of left mandible C incisors of right mandible D setae on dorsal surface of femora E surface and posterior margin of abdominal tergum VII F gill I G gill III H gill VII (flattened on slide) I–K gill VII (in natural position from ventral view) variability in shape L abdominal segments VIII–X in lateral view M sternum IX of female with observed variability.