Frederick Vincent Theobald, British entomologist, was educated in private schools and continued his studies at St John's College, University of Cambridge, where he qualified as Master of Arts (MA). He joined the staff of the South-Eastern Agricultural College in Wye, Kent, in 1894 and by 1911 was its vice-principal. From 1900 to 1903 he was head of the Economic Zoology Section of the British Museum (Natural History). Later he became advisory entomologist to the south-eastern province of England, and professor of agricultural zoology in the University of London.
Theobald was an authority on the mosquitoes of the world and wrote A monograph of the Culicidae or mosquitoes (1901-1910, 5 vols). Other noteworthy publications by him were An account of British flies (Diptera) (1892), The insect and other allied pests of orchard, bush and hothouse fruits and their prevention and treatment (1909), A textbook of agricultural zoology (1899), and many papers on insect pests and collections of mosquitoes from all over the world. He was a Fellow of the Entomological Society, a Fellow of the Society of Tropical Medicine and a member of several European societies, served on the management committee of the Imperial Bureau of Entomology, was an Honorary Fellow of the Royal Horticultural Society and a recipient of its gold medal, and was honoured as an Officer of the Imperial Ottoman Order of the Osmanieh, and Grand Medalliste of the Society Nationale d'Acclimatation de France.
Theobald described 'A new stegomyia from the Transvaal' in The Entomologist (1905). Some years later he reported on a collection of mosquitoes made at Pretoria and Onderstepoort and sent to him by Dr Arnold Theiler*, plus a large collection previously received from C.B. Simpson*, government entomologist of the Transvaal, and specimens from Dr Andrew Copland of Leydsdorp. The study was undertaken to find out which mosquitoes feed on horses and hence may transmit horse-sickness (the cause of which was as yet unknown). His report, which included descriptions of new species, comprised a complete list of all Culicidae so far recorded in the Transvaal. Entitled 'The Culicidae of the Transvaal', it was published in the First Report of the Director of Veterinary Research (1911, pp. 232-272). It was followed by his 'Second report on the mosquitoes of the Transvaal' in the Second Report of the Director of Veterinary Research (1912, pp. 315-342).