Abai, MR

6th International Congress of DipterologySinistral coiling observed in the aedeagus of Phoridae(Insecta: Diptera)Nakayama, H.Biosystematics Laboratory, Graduate School of Social and Cultural Studies, KyushuUniversity, Fukuoka 810-8560, JapanThe epandrium and hypandrium in the male genitalia of the Phoridae areknown to show left-right asymmetry. The aedeagus of the male genitalia inthe Phoridae also shows asymmetric feature, but components of theaedeagus have been uncertain. The genera of the subfamily Phorinae sensuSchmitz were investigated, and their aedeagi to form asymmetric structurewere examined. The aedeagus of Phoridae examined consists of only twomajor sclerites, inner core plate and outer jacket plate. Inner core plate isnearly tube-shaped and its proximal portion is modified to a ring which iscalled the basal ring by phorid researchers. Outer jacket plate is derivedfrom right lateral portion to dorsal portion (when proximal-distal axis ofthe aedeagus is parallel to long body axis) and extends to the left sidethrough ventral portion of the core plate. The jacket plate always surroundsthe core plate counterclockwise (in anterior (proximal) view), and also assinistral coiling. The basal ring is often twisted a little clockwise (inanterior (proximal) view). This feature of the aedeagus is common togenera examined. The genus Stichillus has simple tube-like aedeagus, andit is different from the general type consisting of the core and the jacket.Outer jacket plate in Stichillus, however, should be reduced to a small armon inner core plate. Simple tube-like aedeagus in Stichillus is regarded asbare core plate without the jacket plate. Morphology of phorid aedeagusconsisting of inner core plate and outer jacket plate is spiral, and similar toshell coiling to some extent, but coiling direction is always sinistral.Key Words: aedeagus, basal ring, male genitalia, Phoridae, sinistral coiling∗∗∗∗∗∗∗∗∗∗175