Cat flea. Coloured scanning electron micrograph (SEM) of a cat flea (Ctenocephalides felis). Its body is laterally-flattened to allow it to move easily through the fur of its cat host. The flea's antennae can be withdrawn into its head. One of Its eyes (red) is seen at centre right. The comb-like spines (ctenidia, centre) help to anchor the flea to the host's fur. The mouthparts are modified to pierce the skin and suck blood. Most fleas remain on their host only while feeding. Magnification: x80 when printed 10 centimetres high.