Abstract
Eighty one specimens of nhodeus sericeus (Pallas, 1176) were collected at the upper stream of the Som River (37$^{\circ}$32' 38" N, 127$^{\circ}$58' 57" E: Maegok-ri, Konggun-myon, Hoengsong-gun, Kanguvon-do, Korea) which is a tributary of the Namhan River. This is the first report of the species in the southern part of the Korean Peninsula. This species is well discriminated from the other species in the genus nhodeus by the following respects. The number of scales of transverse series is more than 34 (range 34-37, mean 35.7 $\pm$0.7). Head is echo감or and snout is Bonder than those of the other species. The upper part of the eve is always black and the lateral body surfaces are reddish purple. It had been hem that the southern limit of the distribution of Rhodeus sericeus was the Yonghung River in Hamgvongnam-do, north-eastern part of the Korean Peninsula. But their distributional range is extended more southerly to the Han River system which tons westward through the central part of the Korean Peninsula.Peninsula.
