Cicadas, Hoppers and Aphids are all part of the Hemiptera Order. They live on all continents except Antarctica. Cicadas live underground for several years, surfacing only for their final molt. They feed by sucking the sap of trees such as oak, cypress, willow, ash and maple. Male cicadas sing during the hot summer weather by contracting and relaxing their internal muscles, which creates a clicking sound. Aphids are small sap-sucking insects that can be found worldwide and are known as one of the most destructive insects for cultivated plants as they frequently transmit plant viruses when they feed. Aphids were responsible for spreading the blight of the Irish potato famine of the 1840s. They can be controlled by using insecticidal soaps or by introducing lady beetles or parasitic wasps to your garden.