Harold Powell was a pharmacist. Foreign part of his life he lived in Hyeres.He collaborated with Charles notably on Faune des Lepidopteres de la Barbarie. Etudes de Lepidopterologie comparee, part 10, p.
Rennes, 1914. text online plates online. His collection of Lepidoptera from Morocco is held by Service de la Défense des Cultures, Rabat. He was a Fellow of the Royal Entomological Society.