In the ‘wheel’ position — Common Bluetails mating. The male (bright blue) transfers sprem from the main genital opening near the end of his tail to secondary genitalia on segment two of his abdomen (close to where his tail joins his body). He holds the female behind her head with the end of his abdomen while sperm is transferred from his secondary genitalia to her genital opening. Did you follow all that? Sounds complicated! Photo Harry Ashdown.