Fleas use whatever material they are living in to make the cocoon. Blue carpet fibers will result in a blue cocoon. Fleas are most protected from traditional insecticides during the pupal stage. Fleas develop into adults and remain in their cocoons until conditions are conducive to successful reproduction. One female cat flea can lay between 158 to 420 eggs in her lifetime.
Some estimates are higher.
Table 1 has the development time for each stage of the flea life cycle. For Each Stage Of The Flea Life Cycle. You should complete this control program in one day for maximum success. Always follow the label directions. Also, clean and treat the pet's bedding and resting areas.