British entomologist. Guy Marshall was born in Amritsar, Punjab, son of Colonel Charles Marshall, then district judge, and Laura Pollock, daughter of Sir Frederick Pollock, First Baronet and Chief Baron of the Exchequer. Both his father and his uncle, Major-General George Marshall (who became Chief Engineer and Secretary to the Government of Punjab), were naturalists and had published books on the birds and butterflies of India, Burma (Myanmar), and Ceylon (Sri Lanka). At an early age he was sent to a preparatory school in Margate where, encouraged by his headmaster, he collected butterflies. He switched to beetle collecting as a less conspicuous hobby when he entered Charterhouse. In 1891, after he failed the Indian Civil Service examinations, his father packed him off to Natal to earn a living at sheep farming. He worked at several different jobs before moving to Rhodesia, where eventually he became co-manager of the Salisbury District and Estates Company and part owner of a store and two farms, one of which was managed by C.F.M. Swynnerton before he became a game warden and tsetse researcher in East Africa.

By 1896 Marshall was exchanging letters with the well-known Darwinian, Professor Edward Poulton, Hope Professor of Zoology at Oxford and author of The Colours of Animals (1890), who encouraged him to study the significance of insect colours in mimicry and protective resemblance. It was in the course of this research that Marshall collected plant specimens in southern Africa. The results of this long series of pioneer experiments were published as a joint paper in Transactions of the Entomological Society of London in 1902.

Professor Poulton was later instrumental in securing a curatorial appointment for his protégé at Sarawak Museum. Marshall, however, was prevented from taking up the post when he fell seriously ill, with a disease he had contracted in Africa, while stopping-over in London. After being released from hospital, he settled in the capital, where the publication of some scientific papers on weevils led to his appointment as scientific secretary to the Entomological Research Committee (Tropical Africa). Later renamed the Imperial Bureau of Entomology and then the Commonwealth Institute. The main function of this organisation was to act as a centre of information on insect pests. Under Marshall's direction it became a scientific body of major importance in the Commonwealth and a model for all the agricultural information services that were finally brought together as the Commonwealth Agricultural Bureaux (CAB).

He created the biological control service at Farnham House, which grew rapidly into a worldwide network of laboratories, and founded two important scientific publications: the Bulletin of Entomological Research, which was intended to make the work of entomologists working in the British colonies better known, and the Review of Applied Entomology, which provided much-needed summaries of current publications for an expanding field of research. His organisation later took on the onerous tasks of preparing the 'Insecta' section of the Zoological Record and of identifying insects sent in by Commonwealth entomologists.

In 1916 the University of Oxford conferred on him an honorary doctorate for his contribution to economic entomology. After the war he exerted even greater influence on the development of this field when he was made Adviser on Entomology to the Colonial Office. Nearing retirement he became interested in commercial entomology and founded one of the first pest control companies. He was elected to the Royal Society, the American Academy of Science, the Royal Society of New Zealand, the National Institute of Science of India, the Entomological Society of Belgium, the Entomological Society of Russia, and the Royal Entomological Society of London. He received the CMG in 1920, a knighthood in 1930, and, to mark his retirement, the KCMG in 1942. He also received l'Ordre de la Couronne from the Belgian Government.

After leaving Africa, Marshall engaged in no further experimental research, although he developed a broad knowledge of insect taxonomy through his identification work at the institute. The beetles of the family Curculionidae became his speciality only by accident, because they were the only group in his beetle collection that survived the passage to England on his leave in 1896. He described about 2,300 new species and wrote about 200 papers about them. After his retirement, the Natural History Museum in London provided him with a room in which to continue his systematic studies, which he did until a few weeks before his death.

Sources:
1959, Nature, 183: 1364
W.J. Hall, 2004, "Marshall, Sir Guy Anstruther Knox (1871-1959)", Oxford Dictionary of National Biography
W.R. Thompson, 1960, "Guy Anstruther Knox Marshall: 1871-1959", Biographical Memoirs of Fellows of the Royal Society, Nov 1960: 168-181.