"... speaking here as a taxonomist to taxonomists, I am certainly no less than respectful toward the noble art of classification" (Léon Croizat, 1958, p. 119). In considering a thorough systematic study a necessity before entering into zoogeographical theories, the author feels he may expect the full and sympathetic approval of Professor H. Boschma, to whom this paper is dedicated. Indeed, taxonomy or systematic zoology is one of the corner-stones of a sound building of zoogeography. The present paper, therefore, dealing with the taxonomy of wood owls and subsequent zoogeographical inferences probably is in line with the way of thinking of Boschma as a systematist. The author will add a further perspective of systematic zoology by proposing a way leading to deeper understanding of owl taxonomy through laboratory experiments, which, however, he has not yet been able to carry out himself. James Lee Peters (1940), the latest reviewer of the owls in his "Check-list of birds of the world", volume 4, was confronted with the problem of designing a systematic arrangement of the group of "wood owls", mediumlarge owls with big round heads without ear-tufts and usually dark eyes. In a preliminary paper Peters (1938) turned back to a classification of owls proposed by Sharpe (1875) and more or less strictly followed by Ridgway (1914), using the size and shape of the external ear as a character distinguishing between a "bubonine" and a "strigine" group of owls, ultimately giving these groups subfamily rank.