There are at least 26 species of giant millipedes in this genus, found in Africa, Madagascar, and Arabia. Reaching 15 inches in length, they are the largest of the 10,000 species of millipedes, which form their own arthropod class, distinguished by having two pairs of legs on most of their segments. Giant millipedes have around 250 legs. In contrast to centipedes, they feed only on plants, often decaying leaves. Members of this genus do well in captivity, eating all sorts of fruits and vegetables. They may live at least seven years.