Homoptera may or may not have wings. All have sucking mouthparts. Wings, when present, are four in number and are held roof-like over the body and are usually membranous. Cicadas and leafhoppers all have wings. Aphids may or may not have wings and are small, typically with a pair of projections (cornicles) arising from the fifth or sixth abdominal segment. Scale insects are wingless; live on branches, roots and leaves; and move around little, if any, after beginning to feed. The body is covered with a hard or waxy covering. Mealybugs are usually wingless; whitish or gray in color; covered with a waxy substance; and move slowly.
All Homoptera feed on plants. Mouthparts are formed for piercing and sucking and the beak arises from the hind part of the head. Leafhoppers, aphids, etc. come in many shapes and sizes. Some species in the order Homoptera give birth to living young.
Metamorphosis is generally considered to be gradual but it is modified in whiteflies and some other Homoptera. Most forms are small or microscopic, cicadas are nearly 3/4-inch long.