Resumen:
A new species, Julolaelaps tritosternalis, of the family Laelapidae is described based on adult females and males of one new species from Northern Iran. These mites live associated with Ommatoiulus caspius (Lohmander) (Diplopoda, Julidae). Several morphological characteristics are noted, including the presence of a ventral disc-like structure on the tritosternal base, sternal shield with anteromedial convex protuberance, lack of setae z1, z3, z6, S1 and all deutonymphal setae r, convex alveolar protuberances for setae st1-st5, lack of setae v-2 on genu I and male with hypertrophied dentate movable cheliceral digit. A key to species of Julolaelaps is provided.