Summary1This communication is the substance of a report on a survey of the aphis population in certain districts of Scotland carried out from 24 July to 4 August 1936.2Forty‐three centres in eastern Scotland, from Midlothian in the south to Ross‐shire in the north, were examined by the standard method for determining the aphis “index” figure.3The varying figures obtained have been analysed with a view to establishing any relation there might be with (a) proximity to winter host plants, and (b) meteorological conditions such as temperature, humidity and wind velocity.4The results have been summarized in a discussion in which are indicated the special precautions necessary to ensure health in seed‐pota