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spider,organism, mostly terrestrial, of the class Arachnida, order Araneae, with four pairs of legs and a two-part body consisting of a cephalothorax, or prosoma, and an unsegmented abdomen, or opisthosoma.
The cephalothorax is covered by a shield, or carapace, and bears eight simple eyes. On the underside of the head (the cephalic part of the cephalothorax) are two pairs of appendages, the anterior pair called chelicerae and the second pair pedipalps, with which the spider captures and paralyzes its prey, injecting into it venom produced in the poison glands. The spider then liquefies the tissues of the prey with a digestive fluid and sucks this broth into its stomach where it may be stored in a digestive gland.
Breathing is by means of tracheae (air tubes) or book lungsbook lung,
terrestrial respiratory organ characteristic of arachnids such as scorpions and primitive spiders. Each book lung consists of hollow flat plates. Air bathes the outer surface of the plates and blood circulates within them, facilitating the exchange of gases.
..... Click the link for more information. , or both. Arachnid book lungs are similar to the gill books of horseshoe crabshorseshoe crab,
large, primitive marine arthropod of the family Limulidae, related to the spider and scorpion and sometimes called a king crab (a name also used for the largest of the edible true crabs).
..... Click the link for more information. but are internal and adapted to a terrestrial habitat. Young, growing spiders can regenerate missing legs and parts of legs.
Three pairs of spinnerets toward the tip of the abdomen produce protein-containing fluids that harden as they are drawn out to form silk threads. Several kinds of silk glands and spinnerets produce different kinds of silk used variously for constructing cocoons or egg sacs, spinning webs, and binding prey; other light strands are spun out for ballooning, or floating, the spiders, especially young ones, long distances on air currents. Spider silk is used for the cross hairs in certain optical instruments.
Spiders live chiefly on insects and other arthropods; some large spiders ensnare and kill small snakes, birds, and mammals. Many are cannibalistic; the female may eat the male when courtship and mating are completed. Most species are solitary, but a few live socially. Several species of spiders have bites that are exceptionally painful, or even dangerous to humans. Species of black widowblack widow,
poisonous spider of the genus Latrodectus, found throughout North and South America and common in the SW United States. The name derives from the fact that the female, like those of many other spider species, may eat the male after mating.
..... Click the link for more information. spiders, which are found in the warmer parts of the world including the United States and S Canada, have a virulent neurotoxic venom. The bite venom of the brown recluse spiderbrown recluse spider
or violin spider,
poisonous nocturnal spider, Loxoceles reclusa, most common in the SE and S central United States. Adults are 3-8 in. (10 mm) long and are light brown with a dark, violin-shaped mark on the back near the head.
..... Click the link for more information. of SE and S central United States decomposes tissue, resulting in slow healing and sometimes leaving a sunken scar as large as a quarter.
Among the more interesting spiders are the tarantulatarantula
, name applied chiefly to species of the large, hairy spiders of the family Theraphosidae of North and South America, Africa, S and SE Asia, and Australia. The body of a tarantula may be as much as 4 in. (10 cm) long and, with legs extended, more than 10 in. (25.
..... Click the link for more information. ; the trapdoor spidertrapdoor spider,
burrow-dwelling spider of the Old and New Worlds. Trapdoor spiders dig burrows, which they line with silk and protect by constructing one or two circular, hinged trapdoors. The spiders emerge through the snug-fitting camouflaged doors to search for prey.
..... Click the link for more information. , which ambushes its prey from a silk-lined burrow covered by a hinged lid; the orb weavers, which spin beautiful circular webs; the diving bell spider, which lives underwater and uses a silk-enclosed air bubble to breathe; and the crab spider, jumping spider, and wolf spider, named for their habits. Spiders are classified in the phylum ArthropodaArthropoda
[Gr.,=jointed feet], largest and most diverse animal phylum. The arthropods include crustaceans, insects, centipedes, millipedes, spiders, scorpions, and the extinct trilobites.
..... Click the link for more information. , class Arachnida, order Araneae.
See B. J. Kaston, How to Know the Spiders (3d ed. 1978); R. F. Foelix, Biology of Spiders (1982); The Audubon Society Field Guide to North American Insects and Spiders (1992).
spiderThe diagonal support in a Newtonian telescope.
Beginning in 1931, the Spider, a character created by author Grant Stockbridge (pseudonym of Norvell Page), emerged as one of the most popular heroes of pulp magazine fiction. Two years later, his popular adventures supported the formation of a monthly magazine, The Spider, with episodes that would be gathered at a later date and reissued in books. The Spider dedicated itself to the task of killing criminals and worked as a vigilante outside of the law and public approval. In 1935, on the heels of the popularity of Bela Lugosi‘s Dracula (1931), the Spider encountered one of its most horrendous foes, the Vampire King, and began the process of destroying this evil royalty.
The Spider was the secret identity of wealthy businessman Richard Wentworth. After donning a free-flowing uniform complete with hood and cape, a bullet-proof vest, false teeth, and mask, Wentworth turned into a crime fighter on the streets of New York City. The Spider’s major assets were agility, intelligence, and determination. It was strong and acquitted itself quite well in hand-to-hand fighting. Its major weapon, above and beyond normal weapons like handguns, was a gun that squirted a gooey liquid that formed a web, entrapping its target. Unlike modern superheroes, the Spider had no supernormal powers. It did have a sidekick, Ram Singh from India, who served as his ultimate back-up system.
The Vampire King, the 1930s equivalent of the super villain, was a monster from South America. It is modelled not on the European vampire, but on the camazotz, the Mayan bat god/demon who made its most memorable appearance in the ancient text, Popol Vuh. It appeared as a large bat-man with exaggerated and somewhat grotesque features, including huge ears, wings, and claw-like hands with slender, elongated fingers. It did not possess supernatural powers and could not, for example, change his outward form. It was adept at flying and had great physical strength. The Vampire King’s greatest asset, however, was the control over a large flock of vampire bats, which he could command to attack. Two South American natives accompanied him and used poisonous darts. Two huge half man/half animal monsters also accompanied him—a pig-man and an armadillo-man.
The final confrontation between the Spider and the Vampire King occurred after the Spider’s capture. While the Vampire King conversed with the crime bosses to negotiate control of their North American enterprises, it drank the Spider’s blood, which had been drained into a chalice. The Vampire King offered the criminals a sip as a means of sealing their evil pact. The Spider recovered just in time and his comrades appeared to assist it. The fight that ensued led to the Vampire King’s destruction.
The Spider was brought to the screen in several Saturday matinee serials of the 1930s, but the Vampire King was not among its movie foes. Although a major source for contemporary superheroes, and seemingly a direct inspiration for Spiderman, the Spider was all but forgotten except with a few movie buffs, when, in 1991, he was revived by Eclipse Books in a new comic book series.
What does it mean when you dream about a spider?
A common household spider may symbolize the intricate web that the dreamer has woven or a web that has entrapped the dreamer. Alternatively, it may indicate feeling entangled in a sticky, clinging relationship.
ii. A system of pitch control in helicopters' rotors. The arms of the spider are connected to the leading edges of the rotor blades by control rods, and the spider spindle is situated inside the rotor shaft. When cyclic pitch changes are made, a ball joint mounting allows the spider to tilt. Collective pitch changes are made by raising or lowering the whole spider.
The algorithm used to pick which references to follow strongly depends on the program's purpose. Index-building spiders usually retrieve a significant proportion of the references. The other extreme is spiders that try to validate the references in a set of documents; these usually do not retrieve any of the links apart from redirections.
The standard for robot exclusion is designed to avoid some problems with spiders.
Early examples were Lycos and WebCrawler.
spider(1) Also known as a "crawler," "robot" (bot) and "intelligent agent," a spider is a program that searches for information on the Web. Spiders are widely used by Web search engines to index all the pages on a site by following the links from page to page. The search engine summarizes the content and adds the links to their indexes. Spiders are also used to locate Web pages that sell a particular product or to find blogs that have opinions about a product. See surface Web and bot.
(2) Software that indexes a single website for browsing offline. See offline browser.
(3) (Spider) A gaming platform from AMD. See Phenom.