In his Systema Naturae of 1758, Carolus Linnaeus divided the Order Primates into four genera: Homo, Simia, Lemur, and Vespertilio. His Vespertilio included all bats, and has since been moved from Primates to Chiroptera. Homo contained humans, Lemur contained four lemurs and a colugo, and Simia contained all the rest — it was, in modern terms, a wastebasket taxon for the primates. Linnaeus did not think that Homo should form a distinct group from Simia, classifying them separately mainly to avoid conflict with religious authorities. If we take this into account, Simia (including Homo) would be roughly equivalent to the Suborder Haplorrhini of the Primates (while Lemur would be roughly equivalent to the Suborder Strepsirrhini).
Homo, Lemur, and Vespertilio have survived as generic names, but Simia has not. All the species have since been moved to other genera, and in 1929, the International Commission on Zoological Nomenclature ruled in its Opinion 114 that Simia be suppressed. The genus Simias is distinct and remains valid, containing a single species, the pig-tailed langur (Simias concolor).
The original genus Simia came to include these species:
| Modern genus | Modern common name | Original scientific name |
|---|---|---|
| Carlito | Philippine tarsier | Simia syrichta |
| Callithrix | Silvery marmoset | Simia argentata |
| Common marmoset | Simia jacchus | |
| Leontopithecus | Golden lion tamarin | Simia rosalia |
| Saguinus | Brown-mantled tamarin | Simia leonina |
| Red-handed tamarin | Simia midas | |
| Cotton-top tamarin | Simia oedipus | |
| Cebus | White-fronted capuchin | Simia albifrons |
| White-headed capuchin | Simia capucina | |
| Tufted capuchin | Simia apella | |
| Simia fatuellus | ||
| Saimiri | Common squirrel monkey | Simia sciurea |
| Alouatta | Red-handed howler | Simia belzebul |
| Venezuelan red howler | Simia seniculus | |
| Ateles | Red-faced spider monkey | Simia paniscus |
| Lagothrix | Brown woolly monkey | Simia lagotricha |
| Pithecia | White-faced saki | Simia pithecia |
| Chiropotes | Black bearded saki | Simia chiropotes |
| Callicebus | Black titi | Simia lugens |
| Atlantic titi | Simia personatus | |
| Chlorocebus | Grivet | Simia aethiops |
| Green monkey | Simia sabacea | |
| Cercopithecus | Moustached guenon | Simia cephus |
| Diana monkey | Simia diana | |
| Simia faunus | ||
| Greater spot-nosed monkey | Simia nictitans | |
| Macaca | Crab-eating macaque | Simia aygula |
| Barbary macaque | ?Simia cynamolgos | |
| ?Simia cynomolgus | ||
| Simia inuus | ||
| Simia sylvanus | ||
| Southern pig-tailed macaque | Simia nemestrina | |
| Lion-tailed macaque | Simia silenus | |
| Toque macaque | Simia sinica | |
| Papio | Hamadryas baboon | Simia hamadryas |
| Yellow baboon | Simia cynocephalus | |
| Mandrillus | Mandrill | Simia sphynx |
| Simia maimon | ||
| Pygathrix | Red-shanked douc | Simia nemaeus |
| Pongo | Bornean orangutan | Simia pygmaeus |
| Simia satyrus | ||
| Pan | Common chimpanzee | Simia satyrus |
| Simia troglodytes | ||
| (unknown) | Simia apedia | |
| Simia morta | ||
| Simia trepida | ||
| Simia veter |