Flatidae are a family of fulgoroid planthoppers. They are cosmopolitan in distribution and are distinguished from others in the superfamily by a combination of characters. Like all other planthoppers, they suck phloem sap of plants. Some species are known to communicate with vibrations through the plant stems. Communication may be with mates, or with ants that tend the nymphs, protecting them and gathering honeydew secretions. Adults of some species have brightly coloured forewings which are tougher and known as tegmina unlike the membranous hindwings which are used for flight. Although a few can be identified by their coloration, most species requires dissection and examination under a microscope with access to literature on already described species. There are two subfamilies within the family. In the subfamily Flatinae, the body of adults is flattened laterally and the tegmina are tent-like. In the Flatoidinae, the body is not laterally compressed and the tegmina are not as tent-like and sometimes held horizontally. The wing venation is distinctive in that the veins in the anal region are nodose, and the costal area has numerous cross veins. The antennae are small and the first segment is collar-like and small. The second segment is longer and ends in a bulge and a flagellum arises from it. They have two ocelli. Nymphs have a tail of waxy filaments. Subfamilies and genera Genera within the family Flatidae include: Flatinae Auth.: Spinola, 1839; selected genera: tribe Ceryniini Distant, 1906 Adelidoria Metcalf, 1952 Adexia Melichar, 1901 Bythopsyrna Melichar, 1901 Cerynia Stål, 1862 tribe Flatini Spinola, 1839 subtribe Flatina Spinola, 1839 Flata Fabricius, 1798 Flatomorpha Melichar, 1901 subtribe Lawanina Melichar, 1923 Cromna Walker, 1857 Lawana Distant, 1906 Oryxa Melichar, 1901 subtribe Phyllyphantina Melichar, 1923 Paracromna Melichar, 1901 Phyllyphanta Amyot & Audinet-Serville, 1843 subtribe Scarpantina Melichar, 1923 Scarpanta Stål, 1862 Scarpantina Melichar, 1901 subtribe Siphantina Melichar, 1923 Siphanta Stål, 1862 tribe Nephesini Distant, 1906 subtribe Cryptoflatina Melichar, 1923 Cryptoflata Melichar, 1901 Metcalfa Caldwell & Martorell, 1951 Ormenaria Metcalf & Bruner, 1948 Ormenoides Melichar, 1923 subtribe Nephesina Distant, 1906 Neomelicharia Kirkaldy, 1903 Nephesa Amyot & Audinet-Serville, 1843 subtribe Phaedolina Melichar, 1923 Phaedolus Karsch, 1890 subtribe Pseudoflatina Melichar, 1923 Caesonia Stål, 1866 Colgar Kirkaldy, 1900 Colgaroides Distant, 1910 - Planthoppers Dalapax Amyot & Audinet-Serville, 1843 Gyaria Stål, 1862 Gyariella Schmidt, 1924 Pauliana Lallemand, 1950 Rhinophantia Melichar, 1901 tribe Phantiini Melichar, 1923 Mesophantia Melichar, 1901 Microflata Melichar, 1901 Phantia Fieber, 1866 tribe Phromniini Distant, 1906 Dermoflata