Roland Trimen FRS (29 October 1840 in London – 25 July 1916 in London) was a British-South African naturalist, best known for South African Butterflies (1887–89), a collaborative work with Colonel James Henry Bowker. He was among the first entomologists to investigate mimicry and polymorphism in butterflies and their restriction to females. He also collaborated with Charles Darwin to study the pollination of Disa orchids. Life and career Trimen was born in London in 1840, the son of Richard and Mary Ann Esther Trimen and the older brother of the botanist Henry Trimen (1843-1896) who went to Ceylon (now Sri Lanka). He went to study at Rottingdean and then at King's College School in Wimbledon. Trimen was interested in entomology but a chronic laryngeal condition forced him to move to the Cape of Good Hope as a treatment. Reaching there he volunteered under Edgar Leopold Layard at the South African Museum to arrange the museum's collection of beetles. He joined the Cape Public Service as a clerk in 1860 and later became private secretary to Richard Southey. Still later he served as secretary to Sir Henry Barkly, who was himself a keen botanist. From 1866 to 1867 Trimen served as part-time curator of the South African Museum. In August 1872 he went to Griqualand West as acting private secretary to the governor, Henry Barkley. In January 1873 he was again appointed part-time curator of the South African Museum in Cape Town, succeeding Edgar Leopold Layard. He remained private secretary to the governor and hence could only devote one day a week to the museum. In July 1876 he was appointed full-time curator of the South African Museum in absentia as he had accompanied Premier John Charles Molteno to Britain and only returned in October of that year. He remained in that position until 1895 when failing health caused him to take six-month's leave, at the end of which he resigned his position at the South African Museum. Selected works Trimen studied Cape Lepidoptera in the years prior to his appointment as full-time curator of the South African Museum. He published several journal articles during this time, including: "Entomology of the Cape of Good Hope". Transactions of the Entomological Society of London. (1858-1861). "On some new species of butterflies". Transactions of the Entomological Society of London. (1862-1863). During the early part of 1867 he collected specimens from the Natal area but