Newly developed adults do not leave the cocoon straight away. The '''pupal window''' is the time that it takes for the adult to emerge. Temperature is a large factor in determining when the adult fleas emerge. Some fleas may wait several months before emerging | Newly developed adults do not leave the cocoon straight away. The '''pupal window''' is the time that it takes for the adult to emerge. Temperature is a large factor in determining when the adult fleas emerge. Some fleas may wait several months before emerging |