Evans, William Harry

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Evans, William Harry

(b. Shillong, Assam, India, 22 July 1876; d. Church Whitfield, Dover, England, 13 November 1956)


Evans’ parents were both of military families; his father was General Sir Horace M. Evans (related by marriage to Charles Dickens) and his mother—“the best woman I have known and the greatest influence in my life”—was a keen naturalist, Elizabeth Annie, daughter of Surgeon General T. Tresidder. Conventionally educated at King’s School, Canterbury, and the Royal Military Academy, Woolwich, Evans was commissioned an officer in the Royal Engineers at the age of twenty and retired at fifty-five. Apart from the Somaliland Campaign (1903–1904) and World War I (1914–1918), in each of which he was both wounded and decorated, his entire army career was spent in India. He rose to be a distinguished staff officer and was coauthor of several textbooks on administration and military engineering. It is as a naturalist, however, that he will be remembered.

His first tour of army duty (1900–1901) was in Chitral, on the North-West Frontier of India. His hobby there, with a fellow sapper, Major (later Major General) G. A. Leslie, was collecting butterflies. A joint paper, Evans’ first publication, listed 139 species, of which, despite the attentions of Lionel de Nicéville, the foremost authority in India, ten could be named only doubtfully and nineteen could not be named at all. Although the relevant literature was voluminous and described a great number of individual genera and species, it contained little analytical or comparative data and did not help in naming fresh material. The concept of linking isolated species as geographically separated races or subspecies of one extensive species had not then been adopted.

Evans resolved to document the butterflies of the Indian region a in way that he himself, with no biological training, could understand. He devoted his spare time to study and collecting; his vacations to touring and visiting museums. He searched the literature for all original descriptions and examined practically every type specimen. From 1910 on he published subregional lists for areas not previously covered, and then in 1923 he began to publish a series of papers on classification in the Journal of the Bombay Natural History Society. They were such a success that the Society published them as a volume, Identification of Indian Butterflies (Madras, 1927; 2nd ed., rev., 1932).

Here were gathered 695 generic and nearly 4,400 specific names under 320 valid genera and 1,442 species, all readily identifiable through remarkably concise and practical keys. The various subspecies and synonyms were noted, and the whole was well indexed. An informative introduction dealt comprehensively with structure, classification, collecting, and study. This handy volume, in which not a word was wasted, remains the only work dealing fully with the subject of identification, and many popular treatments have stemmed from it. Thus, by the time he retired, Evans had achieved his ambition and published a standard work of the greatest value to oriental entomologists. But now he planned a greater one.

The Hesperiidae (skippers), one of the largest cosmopolitan families of butterflies, had long been neglected owing to their smallness and drab appearance. Evans undertook to reclassify them. He settled near the British Museum (Natural History) in London and worked there as regularly as the staff. In 1937 the Museum published his Catalogue of the African Hesperiidae... in the British Museum, which, in little more than 200 pages, classified naturally through concise keys 421 species, illustrated 116 species for the first time, and for every species gave diagrams of the male genitalia—features of essential value in distinguishing among this family.

During World War II Evans continued his work in the museum; his deafness was aggravated when a bomb detonated on the road outside the room where he was working on a drawer of specimens, the blast shattering the window and clearing his table, leaving him holding a bare pin. Undeterred, he published further catalogues of the Hesperiidae, of which one (1949) covered those of Europe. Asia, and Australia, and a final four volumes (1951–1955) were devoted to those of the Americas. Thus, a year before he died, Evans had established a complete classification of the Hesperiidae of the world, in which he had marshaled 747 published generic names (over a hundred his own) in 525 recognized genera with 3,000 species and nearly 2,000 subspecies, placing a further 3,300 names as synonyms. Not only had he provided comparative keys for the essential features of each natural subfamily, group, and genus, down to subspecies, but he had also given diagrams of the male genitalia of every recognized species and illustrated the majority of the least-known ones in color, for the first time.


Besides the main works discussed, Evans’ many shorter papers are well listed in The Lepidopterist’s News, 10 (1957), 197–199. Two additions to that list are “Revisional Notes on African Hesperiidae,” in Annals and Magazine of Natural History, ser. 12, 8 , pt. 4 (1956), 881–885; and “A Revision of the Arhopala group of Oriental Lycaenidae,” in Bulletin of the British Museum (Natural History),5 (1957), 85–141.

C. F. Cowan