The Gengidae are a small family of planthoppers from southern Africa, consisting of 2 genera and 4 species. The family, described by Fennah (1949), was erected to house the new genus Gengis and Microeurybrachys transferred from the Eurybrachidae. Subsequently, Fennah (1967) found that Gengis was a junior synonym of Acrometopum Stål, 1853, a genus previously placed in the Issidae, but the family name was preserved following article 40 of the International Code of Zoological Nomenclature. Fennah (1949), considered Gengidae to be near Lophopidae, Eurybrachidae and Ricaniidae, and reconsidered the concepts of those families with respect to his then-new family Gengidae.
Since Fennah (1967), Emeljanov (2007) has described a new species, but little else new has been done with the family and beyond the early speculations, little progress has been made on the phylogenetic position of Gengidae. It was not available to be included in the molecular phylogenetic work of Urban and Cryan (2007) or Song and Liang (2013). Nearly nothing is known – or guessed – of their biology.
In terms of classification, the two genera are (by default) in a single tribe (Gengini) and subfamily (Genginae) following the principle of coordination.
Below is a summary of the classification, details borrowed freely from FLOW.
Family Gengidae Fennah, 1949
Acrometopum Stål, 1853 (= Parametopus Melichar, 1906 synonym of Acrometopum Stål, 1853 by Melichar 1907: 324; Acrometopum Stål, 1853 transferred from Issidae to Gengidae by Fennah 1967: 707; Gengis Fennah, 1949 synonym of Acrometopum Stål, 1853 according to Fennah 1967: 707)
Acrometopum costatipenne Stål, 1855 – KwaZulu-Natal, South Africa (Eastern Cape Province)
Acrometopum panoblites (Fennah, 1949) – KwaZulu-Natal, South Africa (Eastern Cape Province)
Acrometopum theroni Emeljanov, 2007 – South Africa (Western Cape Province)
Microeurybrachys Muir, 1931
Microeurybrachys vitrifrons Muir, 1931 – Cape Provinces (Eastern Cape)
Emeljanov, A. F. 2007. A new species of the genus Acrometopum Stål from South Africa (Homoptera: Gengidae). Zoosystematica Rossica 16(1): 25-26.
Fennah, R. G. 1949. A new genus of Fulgoroidea (Homoptera) from South Africa. Annals and Magazine of Natural History. London. (Ser. 12) 2: 111-120.
Fennah, R. G. 1967. New and little known Fulgoroidea from South Africa (Homoptera). Annals of the Natal Museum 18(3): 655-714.
Melichar, L. 1906. Monographie der Issiden. (Homoptera). Abhandlungen der K. K. Zoologisch-botanischen Gesellschaft in Wien 3: 1-327.
Melichar, L. 1907. Bemerkungen zur Monographie der Issiden (Homoptera). Wiener Entomologische Zeitung 26: 323-324.
Metcalf, Z. P. 1956. General Catalogue of the Homoptera. Fascicle IV Fulgoroidea. Part 18 Eurybrachidae and Gengidae. North Carolina State College, Raleigh, North Carolina.
Muir, F. A. G. 1931. New and little-know Fulgoroidea in the British Museum (Homoptera). Annals and Magazine of Natural History. London. (Ser. 10) 7: 297-314 .
Stål, C. 1853. Nya Genera bland Hemiptera. Ofversigt af Kongliga Svenska Vetenskaps-Akademiens Förhandlingar 10: 259-267.
Stål, C. 1855. Hemiptera fran Kafferlandet. Ofversigt af Kongliga Svenska Vetenskaps-Akademiens Förhandlingar 12: 89-100 .
Stål, C. 1866. Hemiptera Homoptera Latr. Hemiptera Africana 4: 1-276.