Cat flea (Ctenocephalides felis), coloured scanning electron micrograph (SEM). The head (left) is helmet-shaped to assist the flea when moving through the fur (background) of its cat host. The mouthparts are modified to pierce the cat's skin and suck blood. The two stalk-like mouthparts at centre are sensory palps. Parts of the two front legs are at lower left and lower right.