Epeorus (Caucasiron) caucasicus, larva: A labrum (left half in dorsal view, right half in ventral view) with detail of hair-like seta 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 with detail of hair-like seta F gill I G gill III (arrow points on distinct projection on costal margin) H gill VII (flattened on slide) I–K gill VII (in natural position from ventral view), variability in shape L, M abdominal segments VIII–X in lateral view (arrow points on postero-lateral projection) N sternum IX of female with observed variability.