Analysis of collections of Predynastic lithic artifacts from Brunton and Caton-Thompson's excavations in the Badari district, Middle Egypt leads to a revised interpretation of the Badarian and to the recognition of a later Predynastic lithic tradition -- the Mostagedda industry. It is noted that developments in lithic technology from the Badarian to the later Predynastic are sufficient to account for the observed changes in raw material preferences; there is no need to look to the origins of the Badarians to explain their choice of raw material. Both the Badarian and Mostagedda industries appear to represent regional traditions that are restricted to the Badari and adjacent Mostagedda and Matmar areas. Occasional Badarian potsherds found at localities elsewhere in the Nile Valley do no more than suggest some interregional contact with this part of Middle Egypt during the Amratian and possibly the Gerzean. -- AATA