'And as a caterpillar, after having reached the end of a blade of grass, and after having made another approach (to another blade), draws itself together towards it, thus does this Self, after having thrown off this body and dispelled all ignorance, and after making another approach (to another body), draw himself together towards it.

In plain words: A caterpillar reaches the end of one blade of grass, grabs the next one and pulls itself over. In the same way, the Self drops this body and reaches toward another body.