During the past several years we have examined, for helminth parasites, more than 700 specimens of wild birds, which represent 14 orders, 40 families, and 134 species. Although the avian hosts came from various localities throughout the southeastern section of the United States, the greater concentrations were collected from State College, Miss. ; Athens and Augusta, Ga. ; Highlands, N. C. ; Reelfoot Lake, Tenn. ; Eagle Lake and Houston, Tex. ; and Mountain Lake, Va.In the present paper only those trematodes belonging to the subfamily Dicrocoeliinae Looss, 1899, that were studied by us personally are considered in detail. We collected the greater part of the material included in this study, although we have been fortunate in obtaining specimens of several of the species from other investigators.F or the loan of specimens of several species from outside the area covered the writers