Referee's Report by [William Robin] Thompson on a paper 'A contribution to the study of animal populations. The natural control of the Knapweed Gall fly' by G C Varley Paper reference code: B.161 [withdrawn and later submitted as B9 for 1941, but withdrawn again - see RR/W/5/110 and 111 for 1941 reports] Sectional Committee: Zoology States that 'the author deserves encourgement' and the approach taken is 'interesting even ingenious', but that further study is required before the paper is publishable. Questions author's belief that [A J] Nicholssom and [V A] Bailey's theory 'is a great advance on previous theories', pointing to [Alfred J] Lotka and [V] Volterra having worked on the same fundamental assumption as them since the 1920s. Also mentions the work of [William Robin] Thompson and V A Kostitzin. [Not published in Royal Society journals but in the Journal of Animal Ecology, vol. 16, number 2, pp. 139-187, 1947]. Received 29 September 1937 [27 September 1937]