XXXV.—A Contribution to the Ornithology of the Libyan Desert.

The Libyan Desert is described and the specimens collected in the interior by British and Italian workers are listed. Among the otherwise very scanty resident population Falcons are surprisingly abundant. The evidence for migration across the desert is reviewed for each longitude. The Cyrenaican list of passage migrants closely resembles the Egyptian list without its eastern elements. I conclude that a broad-front migration of northern forms takes place at least from long. 21° to long. 31° (600 miles) and that a large proportion of all the birds travelling through N.E. Africa see nothing of the Nile. The new data for several individual forms are discussed, especially Storks and Shrikes.