STRIX. 153 
operculum. In their habits they scarcely differ from other Owls. Their 
eggs are pure white. This genus contains about forty species, which are 
distributed all over the world, except in the Australian region ; and even 
here one species has found its way to the Sandwich Islands. Seven species 
are found in Europe, of which four have occurred in Great Britain. The 
Wood-Owls may be divided into subgenera, either on the presence or 
absence of ear-tufts or on the character of the markings of the underparts 
—in some the transverse bars being principally developed, and in others 
the longitudinal stripes. The first characters are those usually adopted, 
but the latter are probably the most important. 
