Fleas are insects that undergo a complete metamorphosis in the course of their development from egg to adult. The eggs laid by the mother are not, as are the eggs of lice, attached in any way to the skin, fur or feathers of the animal on which the parents are parasitic. They fall into the nest, or drop to the ground within the lair or “ run ” of the host. Hatching takes from three to ten days according to the temperature. The larvae are active, whitish maggots, eyeless and legless, which are not parasitic, but feed on organic matter in the host's bed, or in the dust that collects on the ground in its proximity.