This series is comprised of correspondence between Dornfeld and his colleagues and predominately relates to Dornfeld's interest in lepidoptera. The correspondence includes discussion of butterfly appearances, the publication of Butterflies of Oregon, specimen collecting, identification of butterfly species, and the exchange of field data. A folder designated "Exchange" by Dornfeld includes a partial selection of correspondence relating to the trading of specimens. Similar correspondence can be found throughout Series I.

This series also contains a file titled "Personal Correspondence" which includes correspondence between Dornfeld and Lowell E. Noland, a colleague at the University of Wisconsin. The correspondence includes news of shared acquaintances, information about the work of colleagues in the fields of biology and zoology, discussion of research, and a pamphlet from the dedication of the Lowell E. Noland Zoology Building at the University of Wisconsin Madison.

All materials follow the original arrangement imposed by Dornfeld and are ordered alphabetically according to the surname of the correspondent.

Series II is comprised of subject files and research notes generated by Ernst J. Dornfeld. The files contain locational and behavioral data about a number of Oregon lepidoptera and include maps, articles, manuscript and typescript notes, photographs, slides, correspondence, and specimen samples. The series also contains regional information, Oregon collection station records, and a lepidoptera notebook created by Alton L. Alderman.

Data about specific butterfly species are arranged alphabetically by genus.

Series III is comprised of materials from Dornfeld's teaching career. The series includes correspondence, slides, and transcripts from three lectures on butterflies, materials from a Morphology of the Algae course taken by Dornfeld in 1933, and materials from Oregon State courses lead by Dornfeld. The series also contains information on entomological instrumentation, and photographs and ephemera from the groundbreaking ceremony of Cordley Hall.

This series is comprised of records of Dornfeld's engagement with the Lepidopterists' Society, including his work in the organization of a meeting in Corvallis, and the Oregon Entomological Society. The series also contains materials relating to awards from the OSU Alumni Association and the Oregon Academy of Sciences and a curriculum vita for Dornfeld.

Series V is comprised of publications and materials assembled for publication. The series includes manuscripts, typescripts, notes, and correspondence related to several publications on lepidoptera, image notebooks for histology and cytology, and a history of the Allis Lake zoological laboratory in Milwaukee, Wisconsin. The series also includes Dornfeld's history of the OSU Zoology Department and a later edition published after his death by Charles E. King. Additionally, Series V contains reprints of Dornfeld's publications on cellular biology and includes papers on diverse topics such as the cellular composition of the adrenal gland, rat embryology, and DNA synthesis in isopods.

Series VI is comprised of materials relating to the publication of Butterflies of Oregon. The series contains photographs, maps, and figures to be used in the publication, notes, and an image notebook. The series also includes correspondence and newspaper clippings relating to the book.

This series contains approximately 3000 photographic prints, 2700 negatives, and 18 4X5 inch color transparencies of butterfly specimens. These photographs are arranged according to a numbering system assigned by Dornfeld and were assembled over the course of his career as a lepidopterist. The majority of the prints are black and white and approximately 3 inches by 4 inches. This series also contains a half dozen color prints of varying sizes.