Abstract: Neobychowskyella chelicerus sp.nov (Fig.1) Type specimens:deposited in the Deparment of Biology,Yunnan Teachers University and Simao Teachers College.Host:Pseudecheneis sulcatus (McClelland) Location:Luozha River (Yunxian County,24°28′N,100°07′E),Western Yunnan,China.Description:Minute worm,body size 0.288-0.432×0.060-0.080,pharynx 0.024-0.032,7 pairs of marginal hooklets,4 pairs embryonic type and 3 pairs enlarged,0.025-0.035 in length,2 pairs of anchors;dorsal central large hooks:total length 0.048-0.050,basal portion 0.048-0.050,inner and outer roots not marked,point 0.008-0.010;ventral anchors:total length 0.025-0.026,basal portion 0.020-0.026,inner and outer roots not prominent,point 0.008-0.010.Connective plate a rhomboidal ring,0.006-0.015×0.046-0.051.Connective bars paired,0.004-0.008×0.039-0.048.Accessory pieces 0.004-0.005×0.032-0.035,with an additional chitineous stick,0.020-0.024 in length.Onchium a double striped anchor-like structure and with a crossed scissor-like piece anterior to it.Copulating tuba arched,0.088-0.100 in length,basal diameter 0.004-0.005;supporting apparatus a curved membranous piece with a circular opening on its middle,and through this opening the copulating tube passes.Vagina tubular,0.052-0.083.Egg 0.064-0.073×0.064-0.086.Description based on 5 mounted specimens.