CICADAS: classification                                physical appearance
Cicadas are flying, plant-feeding insects that are most famous for their powerful singing voices and rare appearances.  CLASSIFICATION 2. Cicadas are often mistaken for locusts, but they're actually more like leafhoppers or aphids. They are classified in the Order Hemiptera -- a distinction given to all insects with piercing and sucking mouth-parts. There are over two-hundred species of cicada in the family called Cicadidae. PHYSICAL CHARACTERISTICS  3. The average wingspan of a cicada is between 2.5 cm and 15 cm, depending on their species. They are notoriously bad flyers, and they often run into things if they can get off the ground at all. Cicadas have four wings, and when they are not flying they fold their wings back along the sides of their body. The glassy, transparent, longer fore wing covers the shorter, opaque hind wing. A network of sturdy veins strengthens the two pairs of wings.	4. Cicadas have three pairs of legs, all about the same length. Consequently, they aren't adept at jumping, though they do try. Large, compound eyes situated on each side of their head give them wide peripheral vision. Three tiny eyes on the top of the head (called ocelli) allow them to watch for predators from above. Small, bristle-like antennae are located just behind the ocelli. 5. The cicada's mouth parts are enclosed in a long, thin, beak-like sheath. The sheath, called the labium, is retracted between the legs when the insect is not feeding. The labium contains four needle-like stylets used for feeding. Cicadas feed by piercing the surface of plants with their stylets. They use them like a straw to suck up the sap from plants.
Adapted from: http://science.howstuffworks.com/cicada.htm