Treehopper larvae and adults. Treehoppers (family: Membracidae) are insects that feed on the sap in plant stems. The numerous species take a wide variety of shapes. The larvae (here, white and brown) hatch from eggs and develop into the adult form (here, black and white). Both adult and larval forms feed on the plant sap. Photographed in rainforest at an elevation of 900 metres in the Rio Bigal Biological Reserve, near Sumaco National Park, Ecuador.