Born in Stonehouse and educated at Dulwich College. He joined the navy and was posted as a clerk to HMS Inflexible on 15 January 1896. In March 1910 he was seconded to the Department of Agriculture of the Government of India and then took up entomology, which had previously been a hobby, professionally, being appointed in 1911 Government Entomologist in Madras. Two years later he succeeded Maxwell Lefroy as Imperial Entomologist. He was granted naval retired pay as Fleet Paymaster in November 1915.
On leaving India finally in 1932 he settled at Rodborough Fort, Stroud, a Victorian castellated chateau where he became reclusive and built up extensive collections not only of insects but of books which fuelled his interest in bibliography, stamps and anything else that caught his fancy. Riley records that one room alone was devoted to copies of the Times newspaper, and that one of his eccentricities at this time, which much perturbed his visitors, was to adhere to Greenwich Mean Time year in, year out. He also notes that he was ‘a man of genial disposition, a little shy yet with a ready if sometimes rather mordant wit.’
Fletcher's early publications were on the Lepidoptera but after becoming a professional entomologist he was obliged to cover all the orders. His first major book was Some South Indian Insects, which was profusely illustrated following the example of Lefroy's Indian Insect Life, but with a fuller treatment of the economic aspects. During the next twenty years there followed a series of short notes on the life histories of Indian insects, on crop pests and control measures, official reports, etc. which contained much original matter and were often illustrated by Indian artists. His most comprehensive works at this time were his Keys to the Orders and Families of Indian Insects; Veterinary Entomology for India; Lists of publications on Indian Entomology; and particularly his Catalogue of Indian Insects, which ran to 25 parts most of which he compiled himself. He appears to have published little in the British press on Coleoptera. ‘Lucanus cervus in Gloucestershire’ in EMM., 77, 1941, p.252, being one of the few which is recorded.
He gave several gifts of Coleoptera to the NHM as follows: 50 specimens and other insects from Hong Kong (1898:255); 30 specimens from Korea and Japan (1900:100); 265 specimens and many other insects from Ceylon, etc. (1910:134); 13 Staphylinidae from India (1920:142); 51 specimens from India in exchange for names (1923:285); 1 specimen from India (1925:87); 55 specimens from Switzerland(1925:481 and 1926:147); 39 specimens from Kashmir (1936:627); 6 specimens from India (1928:419); 43 specimens from Pusa (1931:447) and 297 from Kashmir (1932:13). He also gave termites to the HDO. I have seen specimens in the Pusa Institute, Delhi, marked ‘TBF coll’ which presumably refer to Fletcher.
Harvey,J.M.V. et al.(1996) p.78 list an extensive collection of manuscript material associated with Fletcher in the NHM including amongst other material 800 letters to various correspondents, 22 diaries (mostly collecting data covering the period 1921-1947, and five private journals kept while serving on various ships of mainly entomological material. In the RESL are several MS sheets on termites and a notebook covering the period 1905-1912 which includes an entomological journal made in India, March 1911 with photograph and drawings enclosed.(Pedersen (2002) p.48.
There are obituaries in Proc. RESL, (C) 16, 1952, pp.84-85 (by N.D. Riley); Indian J. Ent., 14, 1952, pp. 87-90 (by S.K. Sen and Y. Ramchandra Rao; includes portrait) and in ERJV, 63, 1951, p.100. (MD 12/02, 11/09).