What did Henking observe in his experiments on insects that led to the discovery of sex chromosome ? How did his observation contribute to our understanding of sex determination ?

Henking traced a specific nuclear structure all through spermatogenesis in a few insects, and observed that $\displaystyle 50$ per cent of the sperm received a special structure after spermatogenesis, whereas the other $\displaystyle 50$ per cent sperm did not receive it. This observation later helped in sex determination as ⇒ eggs fertilised by a sperm having X chromosome developed into females. ⇒ Eggs fertilised by sperms not having X chromosome developed into males.