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A taxonomic review of the tribe Melaenini (sensu novo), this paper includes a classification, keys at all taxonomic levels, descriptions (tribe to species), re-rankings, and new synonymy. In total, two genera and 22 species (three of which are new) are treated.

Arrangement of taxa is in the following sequence, with junior synonyms and type localities of new species in parentheses, following name of the taxon. The Eastern Hemisphere genus Melaenus Dejean, 1831 includes M. piger (Fabricius, 1801), and M. elegans Dejean, 1831 (with M. elongatus Chaudoir, 1843, as a new junior synonym), which exhibits marked dimorphism in East Africa. The genus Cymbionotum Baudi di Selve, 1864 includes 20 species, arranged in two subgenera, as follows. The Western Hemisphere Procoscinia, n. subg. (type species, C. fernandezi, n. sp. [Zambrano, Bolivar, Colombia]), includes the type species and C. negrei Perrault, 1994. The Eastern Hemisphere subgenus Cymbionotum (sensu stricto) includes 18 species in three species groups, and three superspecies. The basale species group includes two species: C. semirubricum (Reitter, 1914) (new junior synonyms Graniger aethiopicus Alluaud, 1923, C. minax Andrewes, 1935, and C. a. airense Basilewsky, 1950), and C. basale (Dejean, 1831). The semelederi species group includes three species: C. semelederi (Chaudoir, 1851) (new junior synonyms, Coscinia funerula Fairmaire, 1885, Cymbionotum luniferum Andrewes 1935, and Graniger houskai Jedlicka, 1951), C. striatum Reitter, 1894, and C. mandli Jedli. ka, 1963.

The schueppelii species group includes 13 species arrayed in three superspecies schueppelii superspecies, with three species: C. schueppelii (Dejean, 1825) (new junior synonym: C. capicola rufofasciatum Basilewsky, 1948), C. rufotestaceum (Fairmaire, 1893), and C. capicola (Peringuey, 1908); fasciatum superspecies, with five species: C. helferi (Chaudoir, 1850), C. fasciger (Chaudoir, 1852), C. fluviale Andrewes, 1935; C. pictulum (Bates, 1874), and C. fasciatum (Dejean, 1831) (new junior synonym: Graniger volkonskyi Colas, 1943); and microphthalmum superspecies, with five species: C. namwala, n. sp. (Namwala, Zambia), C. candidum Andrewes, 1935, C. subcaecum, n. sp. (Quetta, Pakistan), C. transcaspicum (Semenov, 1891) (new junior synonyms: Graniger rufotestaceus Pic, 1904 and G. mesopotamicus Csiki, 1929), and C. microphthalmum (Chaudoir, 1876). The taxonomic status of Graniger martini Bedel, 1908 remains doubtful, though it seems highly probable that it is conspecific with C. capicola (Peringuey), and is treated as such.

The elongate diverticulum of the spermathecal gland establishesmonophyly of the Melaenini. Major postulates regarding structural evolution is that, of the two genera, most of the character states of Melaenus are ancestral relative to the character states of Cymbionotum. However, for Melaenus, loss of a pair of supraorbital setae and the posteriolateral pronotal setae, and gain of a transverse microsculpture mesh pattern, fimbriate sculpticells, and markedly convex elytral intervals are apotypic features. Many diagnostic character states of Cymbionotum are reductions or losses: body size, antennal length, elytral striae, metathoracic wing veins, parameral setae, endophallic sclerite x and rami of the ovipositor. Gains are: general body setation, and microtrichiate paraglossae. Within Cymbionotum, prominent changes are: color reduction (loss of melanin from the cuticle); reduction of eyes; reduction of antennomere 2; reduction and increase in setal density and gain and subsequent loss of the clypeal tooth; extension of the pronotum posteriad; and developent and subsequent loss of a beaded posterior margin of the pronotum.

Ecologically, change was probably from rain forest tropical vegetation zone to dry forest, to grassland, marginally to desert/semi-desert, and at least one reversion to the rain forest vegetation zone. Altitudinal change was from lowland to highland. Chorologically, the most striking feature within the extant melaenines is evidence for pre-Cretaceous (or early Cretaceous) origin of both genera, and then evidence of Plio-Pleistocene differentiation from the many allopatric ranges of closely related species. But the distribution patterns provide no evidence about differentiation between the Cretaceous Period and Miocene Epoch. Each of the Neotropical, Afrotropical, Palaearctic, and Oriental Regions has two or more precinctive species, indicating that each region has provided one or more refugia, and hence the isolation required to make allopatric speciation possible.