A subfamily of the Old World monkeys, cercopithecidae, that inhabits the forests of africa and asia. The genera colobus (Procolobus; colobus), Nasalis (proboscis monkey), Presbytis (Semnopithecus; leaf monkey), Pygathrix (Rhinopithecus; snub-nosed monkey), and Simias (pig-tailed langur) all belong to this subfamily.