Abstract
The paper describes a new species and genus of fly, Archidipteron walkeri (Nymphomyiidae: Diptera), found in samples seined by screens from the Molus river, New Brunswick, after spraying of the watershed with DDT in oil.The species is compared with Nymphomyia alba, Tokunaga, of Japan and the affinities of the family discussed. It was concluded that these insects are only distantly related to other Diptera and are probably best considered as belonging in the Archidiptera, a suborder of the Diptera, as proposed by Rohdendorf.The ecological position of the insects is discussed but definite conclusions are not drawn pending more information on life cycle, particularly of the, as yet unknown, larval stages.