Henry John Elwes was one of the greatest traveller-naturalists who have done so much to increase our knowledge of natural history in all branches. A man of means, and possessing great energy and self-confidence, he began when quite young a succession of journeys to different parts of the temperate and, to a less extent, the subtropical regions for purposes of collection and study. He continued these journeys almost without intermission until the First World War.
He started as an ornithologist visiting Sikkim in 1870. At his subsequent visits to Sikkim in the winters of 1875-1876 and 1880-1881 and the summer of 1886 he made, personally and by deputy, a collection which was the basis of his reasoned catalogue of Sikkim butterflies (1888), totalling 530 species. Previously (1881) he had written on the butterflies of Amurland, N. China, and Japan, and in 1886 appeared a monograph of Parnassius. He had become a keen lepidopterist and monographed or published notes on Colias, Erebia and Argynnis. He made numerous trips to the Alps and Pyrenees, and several longer ones in 1885, 1887-1888 and 1893 to the Unites States, Mexico and Canada, accompanied in part by his brother-in-law, F. Godman. For the two years 1893-1894 he was President of the Entomological Society in London. In the summer of 1898 came a journey to the Altai Mountains of Central Asia, which was probably the most successful of all his collecting trips in obtaining new butterflies. In 1899 he was in Bulgaria, in 1901 in Bosnia, and at the end of that year began a useful journey of three months in the Andes of Chile. In 1903 he visited Norway, in 1904 Japan. In 1906 appeared the last of his twenty-eight entomological papers, an account of the rich collections made by the expedition of 1903-1904 to Thibet. In 1912 he visited Formosa, and in 1913 India, entering Nepal.
He was an exceptionally generous donor of specimens to the collection at South Kensington (BMNH, London). During the early years of the last century he presented a good deal of material collected by himself and the valuable Russian collections of Grumm-Grshimailo and Christoph which he had purchased. In all, fifteen butterflies bear his name. He died on 26 November 1922.