Corinnidae is a family of araneomorph spiders, sometimes called corinnid sac spiders. The family, like other "clubionoid" families, has a confusing taxonomic history. Once it was a part of the large catch-all taxon Clubionidae, now very much smaller. The original members of the family are apparently similar only in that they have eight eyes arranged in two rows, conical anterior spinnerets that touch and are generally wandering predators that build silken retreats, or sacs, usually on plant terminals, between leaves, under bark or under rocks.
Castianeira is a genus of ant-like corinnid sac spiders first described by Eugen von Keyserling in 1879. They are found in Eurasia, Africa, and the Americas, but are absent from Australia. Twenty-six species are native to North America, and at least twice as many are native to Mexico and Central America.
Micrathena, known as spiny orbweavers, is a genus of orb-weaver spiders first described by Carl Jakob Sundevall in 1833. Micrathena contains more than a hundred species, most of them Neotropical woodland-dwelling species. The name is derived from the Greek "micro", meaning "small", and the goddess Athena.
Hogna is a genus of wolf spiders with more than 200 described species. It is found on all continents except Antarctica.
Tetragnatha is a genus of long-jawed orb-weavers found all over the world. It was first described by Pierre André Latreille in 1804, and it contains hundreds of species. Most occur in the tropics and subtropics, and many can run over water. They are commonly called stretch spiders in reference to their elongated body form and their ability to hide on blades of grass or similar elongated substrates by stretching their front legs forward and the others behind them. The name Tetragnatha is derived from Greek, tetra- a numerical prefix referring to four and gnatha meaning "jaw". Evolution to cursorial behavior occurred long ago in a few different species, the most studied being those found on the Hawaiian islands. One of the biggest and most common species is T. extensa, which has a holarctic distribution. It can be found near lakes, river banks or swamps. Large numbers of individuals can often be found in reeds, tall grass, and around minor trees and shrubs.
Ctenus is a genus of wandering spiders first described by Charles Athanase Walckenaer in 1805. It is widely distributed, from South America through Africa to East Asia. Little is known about the toxic potential of the genus Ctenus, however, it was recently discovered that the species Ctenus medius shares toxic properties with those presented by Phoneutria nigriventer, such as proteolytic, hyaluronidase and phospholipase activities, in addition to producing hyperalgesia and edema, the venom of C. medius also interferes with the complement system in concentrations in which the venom of P. nigriventer is inactive, indicating that this spider has a noxious venom to humans. The venom of C. medius causes an eleavage in the complement component 3 (C3) of the complement system, it affects the central factor of the cascades of the complement, and interferes with the lytic activity of this system, which causes stronger activation and consumption of the complement components. Unlike C. medius, the venom of P. nigriventer does not interfere with lytic activity.
Eustala is a genus of orb-weaver spiders first described by Eugène Simon in 1895.
Alpaida is a genus of South American orb-weaver spiders first described by Octavius Pickard-Cambridge in 1889.
