Cat flea larva in carpet. Coloured scanning electron micrograph of a cat flea larva (yellow) coiled around fibres in a carpet. The cat flea (Ctenocephalides felis) is a small, wingless, blood-sucking insect. Its maggot-like larvae hatch from eggs on the ground in the cat's 'nest' and feed on organic debris, favouring especially the faeces of adult fleas, which are rich in undigested blood. After moulting twice the larvae spin woolly cocoons and metamorphose into adults. Most of the parasite's life - as egg, larva, cocoon and adult - is spent off the host. Magnification unknown.