Individuals of the predacious mite, Gamasiphis tylophagous El-Borolossy and El-Banhawy, developed faster on the citrus parasitic nematode, Tylenchulus semipenetrans Cobb., than on the acarid mite, Rhizoglyphus robini Claparede. Duration of the adult stage was insignificantly affected by type of prey, although reproduction significantly increased on the nematodes and decreased on the acarid mites. The life table parameters were greatly affected by changing temperature. Below 30 degrees C, individuals developed slower and produced fewer eggs. Other parameters, such as sex ratio, seem not to be affected by temperature.