Abstract
Since the publication of the previous paper (Leeson, 1953), additional information has been accumulated on the geographical distribution of some of the Old World ticks of the genusOrnithodorosand two new species (zumptiandarenicolous) have been described. Much of this additional matter has been communicated to me by correspondents who have been kind enough to give permission for its publication here. Their names are enclosed in brackets after the new data to indicate the source and to these workers I tender my sincere thanks.