抄録
The larvae of Digramma alternans were found on the Japanese dace, Tribolodon hakonensis inhabited Hidaka-horobetsu River in Hokkaido. This is a first finding of D. alternans in fish inhabited rivers in Japan. It was assumed that the first intermediate host (copepods) and the final host (birds) inhabit the swamps which are located around the mouth of the river and lead to it.
