Figure 1. Schematics of female ducts (blue), male flagella (red) and male flagella guiding structures (green).

Spheres on the male flagella show the tips of the male flagella. For simplicity, reversal turns (knots) are not depicted. (a) Mating is just stated; the tip of male flagella guiding structure is inserted to the female duct. (b) The male flagellum is fully inserted into the female duct.