THE MECHANICS OF COPULATION IN AEDES AEGYPTI

¹ Department of Tropical Public Health, Harvard School of Public Health, Boston 15, Massachusetts

1. The aedeagus of the Aedes aegypti male is placed superficially within the genital orifice of the female during copulation and is not a deep intromittent organ. When everted, it rotates through more than 90 degrees and its lobes spread, revealing the genital pore in its base. The paraprocts' function is to distend the genital lips of the female and to elevate the anal cone of the male. During coitus, the sleeve-like atrial membrane of the female is everted, revealing the genital opening at its apex. Sexual union is accomphishd through the junction of the everted aedeagus and the atrial membrane. The anal cone, the aedeagal pouch and time paraprocts assist in the formation of a firm line of union. The mechanics of eversion of the aedeagus and atrial membrane and the details of their juxtaposition are analyzed.

2. It is suggested that contractions of the male accessory glands provide the current in which the sperm are carried to the copulatory bursa of the female, and that the sperm subsequently transfer to the spermathecae.

3. The anatomy of the genital atrium of the A. aegypti female is described. The valves of time lower atrium seal the oviduct of the non-ovipositing female. The dorsal valve is everted during copulation and its spinous outer surface engages the spines of the aedeagus. The spermathecal ducts and accessory gland duct communicate with time atrium through a common chamber.

4. Males receive complex mating stimuli from the female and require auditory as well as other kinds of stimuli before sperm transfer is accomplished.