He was unaware that varieties occurred proportionately more in large genera.
Recommends a work [Leonard Gyllenhaal, Insecta Suecica, 4 vols. (1808–27)] for tabulating varieties.
Lists "close geographical representatives of Europaean species" based on the species numbers [in T. V. Wollaston, Catalogue of the coleopterous insects of Madeira (1857)].