Evolutionary biologist Elisabet Sahtouris says that the caterpillar, at a certain point in its life cycle, becomes a voracious, over consumptive glutton consuming everything in sight and within reach. At this point in its evolution it can eat hundreds of times its own weight, and the more it consumes the more fat and sluggish it gets. At that same moment of developmental excess, inside the caterpillar the imaginal cells begin to stir. Imaginal cells are specialized cells, and in the minority, but when they connect with each other they become the genetic directors of the metamorphosis of the caterpillar. At some point in the caterpillar's feeding frenzy  stage, the imaginal cells usher in the  process in which the over consumptive caterpillar becomes the nutritive soup out of which the imaginal cells create the miracle of the butterfly.