The year is established by the reference to F. B. White 1878 (see n. 2, below).

CD’s annotated copy of White’s ‘Contributions to a knowledge of the hemipterous fauna of St. Helena, and speculations on its origin’ (F. B. White 1878), in the Proceedings of the Zoological Society of London, is in the unbound journal collection in the Darwin Archive–CUL. White argued that fauna colonised the extremely isolated Atlantic island of St Helena from the north along a now submerged chain of island ‘stepping stones’, taking advantage of ocean currents and winds that had since then reversed direction owing to the end of a glacial period (F. B. White 1878, pp. 454–5).