Spiders are found in almost every terrestrial habitat, from deserts to mountain peaks. They cannot fly, but many are able to travel long distances by "ballooning" on silk threads. Most species have eight simple eyes, but some have six, four, two, or no eyes at all. The chelicerae have a hinged fang at the tip, and almost all species have venom glands. A spider's pedipalps are six-segmented and have a sensory function. There are four pairs of seven-segmented walking legs. The abdomen is not segmented and carries silk-spinning organs. When a spider feeds, the body tissues of its prey are dissolved by enzymes in the spider's digestive juices.
 

The eyes of these spiders are arranged in two groups of three, with another pair in between. Typically, the carapace is very round. The legs are much longer than the body, giving a spindly appearance. Coloration is gray, green, or brown, with pale legs. The tarsi are very long and flexible. These spiders make tankled, irregular webs and quickly wrap trapped prey in silk before biting it.
 

Females produce about 15 to 20 eggs, which they wrap in a silk bundle and carry in their mandibles until they hatch.
 

Worldwide. Many tropical species occur in caves or leaf litter. In temperate regions, many species live in the dark corners of buildings.