The chelicerae // are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata (horseshoe crabs), and Pycnogonida (sea spiders). Additionally, some chelicerae, such as those found in spiders, are hollow and contain (or are connected to) venom glands, and are used to inject venom into prey or a (perceived) threat.
Phidippus audax is a common jumping spider of North America. It is commonly referred to as the daring jumping spider, or bold jumping spider. The average size of adults ranges from roughly 13–20 millimetres (0.51–0.79 in) in length. They are typically black with a pattern of spots and striped on their abdomen and legs. Often these spots are orange-tinted in juveniles, turning white as the spider matures. The spider belongs to the genus Phidippus, a group of jumping spiders easily identified both by their relatively large size and their iridescent chelicerae. In the case of P. audax, these chelicerae are a bright, metallic green or blue.
These spiders have been known to jump from 10 to 50 times their own body length by suddenly increasing the blood pressure in the third or fourth pair of legs, and the male may jump away during mating if the female approaches too quickly.
Like other jumping spiders, due to their large, forward-facing eyes, they have very good stereoscopic vision. This aids them when stalking prey, and allows some visual communication with others of their species, such as courting 'dances'.