Francis (Frank) Treleaven was a bookkeeper who collected insects and other land invertebrates for the South African Museum, Cape Town, during the eighteen-nineties. In 1896 he and an employee of the museum, R.M. Lightfoot*, collected a scorpion at Tulbaghweg Station, near the town of Tulbagh. Two years later Treleaven consulted the museum's insect collection and donated various arachnids from the Cape Peninsula, as well as a frog. During 1899 he assisted the museum's entomologist, Dr L.A. P?ringuey*, in collecting some local beetles. He also presented the museum with a collection of land invertebrates, including spiders and insects, made at Kanye, Botswana (some 40 km north-east of Lobatse). A number of species were new to the museum's collections, including a "rare Hymenopterous insect" that had apparently not yet been described.
Treleaven became a member of the South African Philosophical Society in 1896. In 1891 he resided at 24 Dunkley Street, Cape Town; in 1898 in Plein Street; and in 1902 at 5 St John's Terrace, Hatfield Street. At the time of his death in 1902 he had been certified insane. He was presumably the father of Miss S. Treleaven*.