First editions; Parts 1 through 4 of the main work only (the fifth part issued in 1960 not present) and the first bibliography volume (a second issued in 1915 not present); quarto, I. The Argasidae., II. Ixodidae., III. The Genus Haemaphysalis, (with a total of approximately 550 pages, pagination continuous), IV. The Genus Amblyomma by L. E. Robinson. (xii, 302 pp., this was to be the start of a second volume and the pagination started over); all parts are illustrated including plates with some color + Bibliography of the Ixodidae [I]. vi pp., 68 leaves with versos blank (in this copy a few have printed slips pasted on); paper wrappers dulled and some frayed at extremities, hand stamps "Ex libris W. Williamson" in every volume, still overall a very good group. Photos available upon request.