How is David's life similar to that of a caterpillar, cocoon, and butterfly's in The Chrysalids by John Wyndham?
This is an unusual question, but I suppose upon reflection, the three stages of David's psychological development might well be likened to a caterpillar, a cocoon and a butterfly--although the analogy ends abruptly when you recall that butterflies have exceedingly short lives.
The first psychological stage of David's life is when he is having his dreams about the far away land with blue ocean and sky and he is just becoming aware that he has "mutations" that are not common. He is wisely advised to keep silent about it all and he wisely follows the advice. This is when he is a caterpillar.
After Uncle Axel guesses his gift and Petra's cries for help draw the attention of the community upon David and Rosalind, David has every reason to heed Uncle Axel's advice and draw into a cocoon of secrecy that includes the others who share his telepathic gift. This veil of deep secrecy and extraordinary caution, then, is the cocoon stage.
When it is revealed that David and the others are telepaths and David, Petra, and Rosalind begin their flight away from Waknuk, David's metaphoric cocoon breaks open. At the end of their dangerous flight to safety and the group is taken to Sealand, David becomes the beautiful butterfly and flies free--free of secrecy, free of constraint, free of fear--free to practice all the natural talents and gifts he possess--for a long and eventful life, we hope.