Fertilisation of the indigenous species of Anopheles in England, as far as I know, has not been brought about while the insects were in captivity. Several investigators have attempted to induce fertilisation in order to maintain strains for laboratory experimental purposes, but without success. While in charge of the War Office Entomological Laboratories at Sandwich, Kent, during 1919–1920, I attempted to induce fertilisation in captive Anopheles maculipennis and A. bifurcatus, but failed to do so even under the very favourable environment under which the insects were kept—such as large scientifically constructed insect-cages, an electrically heated insect-house, electrically controlled atmospheric humidity, an animal and human blood supply, etc.