Flies of the Nearctic Region aims to provide a concise and complete treatment of the systematics of the diptera of the Nearctic region, i.e. Canada, Alaska and the contiguous United States (including all Florida and the Florida keys and Bermuda). The boundary separating the Nearctic from Neotropical Regions in Mexico is drawn close to the coast (in northern Mexico) by the boundary between desert or mesquite grassland (considered nearctic) and tropical (thorn or deciduous) forest, and in the interior by the boundary between pine-oak forest (nearctic) and tropical (evergreen or deciduous) forest or scrub at lower elevation. All land East and South of the Isthmus of Tehuantepec is considered to belong to the Neotropical Region in the context of this series.
In the Beringian area the present territorial boundary between the United States and the Soviet Union is accepted as the boundary between the Nearctic and Palaearctic Regions. Greenland is part of the Nearctic Region, but Iceland, Jan Mayen and Spitzbergen excluded.
Flies of the Nearctic Region intends to be a companion of the Palaearctic Series (Die Fliegen der Palearktischen Region – Flies of the Palaearctic) under publication since 1924.The editors have been able to secure the support of North American dipterists for initiating this new series because of the high reputation which the Palaearctic series enjoys.
The series is to provide basic reference which will remain in use and continue to be available over an extended period of time. To fulfill this objective all contributions are expected to be original, and to review previously published literature with authority. Flies of the Nearctic Region aims to to consolidate the achievements of North American dipterology during the present century and to provide a sound basis for continuing progress during the next.