Enzio Rafael Reuter (30 March 1867, in Turku – 11 February 1951, in Helsinki) was a Finnish entomologist who specialised in Lepidoptera.
He wrote Über die Palpen der Rhopalocera: Ein Beitrag zur Erkenntnis der verwandtschaftlichen Beziehungen unter den Tagfaltern, an important work on the classification of lepidoptera in which some higher level taxa are erected.
Reuter was a cytologist and student of phylogenetics. His collection is conserved in the Natural History Museum of Helsinki.
Reuter was a correspondent with and admirer of the German Darwinist Ernst Haeckel:
"In 1868 Haeckel had given his first edition of the natural history of creation and this work, more than any other, made Darwinism to a generally accepted world view… Reuter’s dissertation carries a label of its time. It is a typical phylogenetic handling, inspired by Haeckel’s spirit that at the close of the century totally dominated the biological research."[1]