Epeorus (Caucasiron) nigripilosus, 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, J gill VII (in natural position from ventral view) variability in shape K, L abdominal segments VIII–X in lateral view (arrows point on postero-lateral projection) M, sternum IX of female with observed variability.