The Araneae Theraphosae include all those Spiders which construct subterranean tubes, some of which are protected by a trap-door or lid. These are divided into three families-Liphistiidae, Aviculariidae, and Atypidae. Of these, the first, consisting of only one genus, Liphistius, Schiodte, is peculiar to the islands of Penang and Sumatra. The second, Aviculariidae, is divided by Simon into seven sub-families, and representatives of it are found in all parts of the world. The third, Atypidae, although not so numerous as the preceding group, occurs in Europe, America, Africa, Japan, and Malaysia.