The everted endophallus (Plate 15)

1. Kill a mature drone.

2. Examine the partially everted endophallus, and compare it with the drawing in Plate 15.

3. Take the abdomen between the thumb and forefinger and compress it laterally; eversion will continue until the bulb reaches the tip of the organ, when sperm and mucus will be liberated.

In living drones, notice how easily eversion is induced by the slightest pressure, and the 'snap' when this occurs.