Born in Putney the son of David Douglas of Tranent near Edinburgh. Educated at a private school where he received a serious injury to his leg as the result of a practical joke. During the two years convalescence which followed he took up botanical draughtsmanship and, when he regained his health, he joined the staff at Kew Gardens to pursue this interest further. After a few years, however, he left Kew to join the staff at the Customs House where he remained for the next fifty years, reaching a senior position and being personally thanked by Gladstone for his work on the importation of Continental wines. He married in 1843, living first at Camberwell and subsequently at Lee and Lewisham. He died at Harlesden. Douglas's interest in insects began when he was at Kew, and his first article 'Random Thoughts on Entomology' was published in Ent. Mag., 4, 1837, pp.340-342 and 5, 1837, pp.62-65. Although much of his work was on the Lepidoptera (the genus Douglasia was named after him by Stainton), Coccidae, and Hemiptera on which he published his best known work with John Scott The British Hemiptera, vol 1, Hemiptera-Heteroptera, 1865, he also wrote on beetles. His best known articles are probably those on the food and habits of Velleius diltatus in hornet's nests' in EMM., 15, 1879, p.260, ‘Anisoxya fuscula at Lee', ibid., 12, 1876, p.83; and his article on the Colorado beetle, ibid., 13, 1877, p.181. He also published articles in EWI. including one on myrmecophilous beetles (80, 1858, p.16). 'A Proposal for a new catalogue of British Coleoptera', appeared in Zool., 6, 1858, pp.5899-6001. He was also the author of The World of Insects, 1856. In the Ent.Ann., 1865, Douglas states that he was 'at home to entomologists every Friday evening after half past six PM from November to March inclusive'. On Douglas’s collections of Hemiptera see a forthcoming article by Mick Webb. Douglas gave a weevil to NHM in 1843 (43.26) and a further five beetles in 1846 (46.94). A copy of a letter from Janson in the J.W. Ellis collection at Liverpool Museum implies that P.B.Mason acquired the 'entire' Coleoptera collection of Douglas, but if this was the case it is not mentioned by Hancock and Pettit (1981) as among the Bolton material. Harvey et al (1996) record that there are three MS notebooks in the NHM listing captures covering the periods 1848-52, 1853-56 and 1855-96 , and a MS leaf listing his insect collection. Pederson (2002), 121, lists correspondence in the RESL dated 1890 with C.J.Wainwright. Douglas became an editor of the EMM in 1874. Simms (1968) records material in the W.C.Hey collection at York.
FESL from 1845-1862, 1876-1905 (Council 1846, Secretary 1849-56, President 1861). There are obituaries in EMM., 41, 1905, pp.221-22,262 (by E.Saunders); ibid., 42, 1906, p.16 (by C.W.Dale); and in ERJV., 17, 1905, pp.246-248. (MD 9/02, 12/21)