Abstract
A new genus, Monobius Alatawi and Kamran, is hereby proposed for the two already described species, viz; M. electrus (Żmudziński) and M. meyerae (Bolland). In addition, the monospecific genus Tillandsobius Bolland is synonymized with the genus Tycherobius Bolland due to variations in the setae number of tibiae I-IV. Further, the genus Neophyllobius Berlese is categorized in two new subgeneric divisions as Neophyllobius Berlese and Monophyllobius Mirza. The number and position of the midventral setae on tarsi I-IV are considered as strong diagnostic generic and subgeneric diagnostic characters. The present study also includes the key to all known species of the genus Neophyllobius. The morphological characters of ten poorly described Neophyllobius species were studied in detail through published literature. The ambiguities in the ventral idiosoma setal notation are highlighted and discussed. It is concluded that two intercoxal setae 3a-4a are always present on small platelets, paired aggenital setae (ag) are present anteriorly and paired genital setae (g) present posteriorly on genital shield. In addition, five records of new species for Saudi Arabia are reported along with re-descriptions of three species.