Harold Maxwell-Lefroy was an English entomologist. He served as a Professor of Entomology at Imperial College London and as the second Imperial Entomologist to India. He left India after the death of two of his children from insect-borne diseases. He worked on applied entomology and initiated experiments on the use of chemicals to control insects. A formula he developed was utilised to save Westminster Hall from destruction by wood-boring beetles, while others were used to control lice in the trenches during the First World War. The success of his chemicals led to increased demand and the founding of Rentokil, a company for insecticide production. Maxwell-Lefroy's students included Evelyn Cheesman who took up a position at the insect house in London Zoo from 1919. He was killed while experimenting on fumigants to control insects.
