This genus is usually placed with the Brachypodinae, but I cannot discover that it has any close affinities with the Bulbuls.
The birds of this genus have a moult in February in addition to the autumn moult. From February to June the sexes are very differently coloured, but at other times of the year they resemble each other. The colours of the female are not changed by the February moult. The young males resemble the female for some months, and probably assume the male garb in January.
In this genus the bill is very strong, nearly as long as the head, with the culmen nearly straight and the tip strongly notched and hooked; the nostrils are long ovals, and the rictal bristles are weak. The tail is almost square at the end.