Louis B. Prout, an English entomologist and musicologist, was the son of the composer Ebenezer Prout. As a musicologist he wrote several publications on harmony. As an entomologist he specialised in the Lepidoptera (butterflies and moths), particularly the family Geometridae (Geometer moths), on which he was a world authority. His observations and publications formed the basis of the card index of the Geometridae in the British Natural History Museum. He was the secretary of the North London Natural History Society and worked in association with the Natural History Museum at Tring, some 60 km northwest of London.
Prout published dozens of papers on the Geometridae during his career, between 1907 and 1937. Included were descriptions of new species in the Tring Museum (1923, 1926) and in several other collections; new species from Africa (1911, 1915, 1916, 1917, 1926, 1928, 1932) and India (1926); and taxonomic papers dealing with the sub-families of the Geometridae. Some of his papers dealt specifically with new species in South African collections. In the Annals of the Transvaal Museum he described 'New South African Geometridae' (1913, 1916), 'New South African Heterocera' (1922), and 'Scientific results of the Vernay-Lang Kalahari Expedition, March to September 1930: The Geometridae' (1935). He also described new species of Geometridae in the collection of the South African Museum (Annals of the South African Museum, 1917, 1925).