It is proposed that Haemoproteus nettionis (Johnston and Cleland, 1909) Coatney, 1936 be accepted as the correct name for the Haemoproteus of Anatidae. A list of synonyms and amended description of the parasite is given. Infections are reported from wood ducks (Aix sponsa) and from domestic ducks and geese, the last representing a new host record. Natural transmission was demonstrated at the Patuxent Research Refuge, Laurel, Maryland. Possible seasonal variation is suggested with active carriers present as early as mid-April among adult wood ducks and most active transmission occurring in June and early July with limited transmission earlier or later.