Ahmad Nadimi - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box ۱۴۱۵-۳۳۶, Tehran, Iran.
Ali Asghar Talebi - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box ۱۴۱۵-۳۳۶, Tehran, Iran.
Yaghoub Fathipour - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box ۱۴۱۵-۳۳۶, Tehran, Iran.

A survey on the megachilid bees (Hymenoptera: Megachilidae) fauna of northern Iran, between ۲۰۱۰ and ۲۰۱۱, led to the identification of eleven species of the genus Coelioxys Latreille belonging to subgenera Allocoelioxys (۶ species), Boreocoelioxys (۲ species), Coelioxys (۲ species) and Liothyrapis (۱ species). Of these, six species and one subgenus (Liothyrapis) are new to the fauna of Iran. Detailed illustrations of morphological characters, a key to the species of the genus Coelioxys and an updated checklist of Iranian species of Coelioxys are provided.

new record, Coelioxys, cleptoparasitic bee, Megachilidae