A comparison of the structure of the cervical lobes of the drone honey
bee endophallus in 5 species of Apis, using scanning electron microsc
opy, provided evidence of reproductive isolation in the genus. Structu
ral similarities suggest three evolutionary groups: (1) A. mellifera a
nd A. cerana; (2) A. florea and A. andreniformis; (3) A. dorsata. A. d
orsata is separate but closely related to group (1).