Cat flea head. Coloured scanning electron micro- graph of the head of a cat flea (Ctenocephalides felis), seen from the front. At the top is the genal comb, a fringe of spines that stops the flea from falling out of its host's fur. Below this are two splayed sensory palps, which detect odours. In the centre are the blood-sucking mouthparts. These consist of a piercing stylet enclosed between two small labial palps, which form the sheath. Beside these are the hairy, muscular coxae (thighs) of the flea's forelegs. Cat fleas are tiny, wingless, parasitic insects. They visit the host only to feed, using powerful legs to leap between it and the ground. Magnification unknown.