I have been asked by the Imperial Institute of Entomology to identify a beetle found in mushroom-beds in South Africa. This beetle proves to be a new species of Atomaria. The genus Atomaria consists of about 165 species chiefly confined to the holarctic region. One of these, A. linearis, Stephens, is sometimes a serious pest of sugar-beet and mangold, eating the leaves and roots. Other species, e.g. A. nigripennis (Kugelann) and A. atricapilla, Stephens, are found in houses, cellars and warehouses, where they probably feed on fungi.