what species of spiders is the biggest in size?
602084
The Goliath bird eating spider\n-makes noise by rubbing hairs on it's legs\n-one inch fangs that can inflict a very painful but not lethal bite\n-eats young birds, frogs, lizzards bats etc.\n-measures about 30 cm long\n-from the rainforests of south america\n-http://www.extremescience.com/BiggestSpider.htm
528288
Black widow I guess. Not alot of spiders in Utah.
216930
Spiders are not insects. Spiders are members of a large category of animals called Arthropoda. Phylum Arthropoda includes the following groups: \n\n\nClass CRUSTACEA: Crabs, prawns, lobsters etc \nClass CHILOPODA: Centipedes \nClass DIPLOPODA: Millipedes \nClass INSECTA: Insects \nClass ARACHNIDA: Spiders and other Arachnids
1176508
Several answers to your question, actually:\n1) Because they are so effective in their ecological niche, there is no evolutionary pressure to grow any larger -- they do just fine at the size they are currently at.  If growing bigger conferred an evolutionary advantage, they would gradually do so.  And bigger is not necessarily better; since they are not at the top of the food chain, the bigger they get, the more easily they may be spotted by potential predators and eaten.\n\n2) Spiders are physically incapable of growing much bigger than they currently are, because of how they're put together -- since their bodies are supported by an exoskeleton, all their soft tissues are sort of slopping around inside a hard shell, and if they got any bigger, these tissues would only sag under their own weight and become useless.  Also, spiders do not possess a circulatory system like larger animals -- they breathe through "book lungs," which are kind of like gills on the underside of their abdomens and deliver oxygen directly to some of their tissues, while the rest are served by spiracles, little air tubes that lead from various points on their legs through the soft tissues.  Grown any larger, and they simply couldn't have enough transport mechanisms to oxygenate their entire bodies efficiently, and they'd be prone to suffocation.  You'll notice that the larger a spider gets, the more it tends to become spindly -- those big Mexican cave spiders may have a three-foot leg span, but their bodies are still only the size of a small rat and their legs are just long spindly things. \n\n3) As another poster mentioned, what would they eat?  Larger predators require greater energy input to maintain themselves, so unless you're talking about a world full of giant bees and butterflies, it would mean they would evolve to compete in a new niche, hunting small rodents or fish (though one spider actually does catch small fish), competing against snakes, birds, and carnivorous mammals for food.  There's a lot more to eat down where they are in the middle of the food chain than there is at the top.
107819
the largest centipede in the world is ethmostigmus rubripes. They live in Australia. They are 14 cm long. They are apart of the scolopendrid family.
948880
The tarantula everytime. The emporer scorpions sting is very mild, about as potent as a bee sting!! Plus the bird eating tarantula full grown is much much larger than an emporer scorpin full grown. Now if they were the same size it will prob be the tarantula....it's venom is much more powerful.
1071424
A few kinds of spiders are harmful to human beings. In North America, six kinds of spiders harm people, they are - the Brown Recluse, Sac, Black Widow, Brown Widow, Red-legged Widow and the Varied Widow. \n\nWater spiders are the only spiders that live most of their life underwater. The water spider breathes underwater from air bubbles that it holds close to its body. Its underwater nest is a silk web shaped like a small bell. The spider fills the web with air bubbles, which gradually push all the water out of the bell. The animal can live on this air for several months. Water spiders are found only in Europe and parts of Asia.
1064823
SPIDERS!!!!!!!!aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!!!!!
282066
"Largest" is usually based on the overall mass of the animal, not just the length. While anacondas can get considerably longer than crocodiles, they aren't nearly as massive.
297732
Largest: Blue whale (Balaenoptera musculus)\nSmallest: Bumblebee bats (Craseonycteridae)
393918
Doesn't sound familiar, but here's a link to an article about North America's "medically significant" spiders. take a look at the photos. If it's not on here, chances are you don't have to worry about it.\n\nhttp://www.royalalbertamuseum.ca/natural/insects/research/dangspid.htm
786900
Your spider is absolutely positively a Zoropsis spinimana. \n\nPhoto here: \nhttp://www.calacademy.org/science_now/invasive_species/zoropsis_spinimana.html\n\n"These large spiders are currently invading the San Francisco area."\n\nPhoto here:\nhttp://spiders.ucr.edu/images/zorspi.jpg\n\nDiagram of identifying marks and patterns:\nhttp://www.americanarachnology.org/JoA_free/JoA_v29_n1/arac_29_01_0111.pdf\n\nArticle and photo:\nhttp://www.physorg.com/news10271.html\n\n"San Francisco Bay-area residents are being asked to help keep track of a new arrival -- the Zoropsis spinimana spider.\n\nThe spider, a native of Mediterranean and northern Africa coastal countries, is brown with grayish spots. It's about two inches in length when it stretches its legs. \n\nScientists aren't certain when or how the arachnid migrated to Northern California, but they told the San Francisco Chronicle it is an apparently harmless spider."\n\nArticle: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/01/26/BAGHRGT0E11.DTL\n"House spider migrant setting up in Bay Area \nScientists ask public for help in studying how species adapts\nZoropsis seems to be harmless: Calm and slow-moving, it didn't try bite or otherwise hurt Darrell Ubick, an expert at the California Academy of Sciences, who placed a member of the species on his arm. \n\nStill, Ubick and his academy colleague, entomologist Charles Griswold, are asking Bay Area residents to watch for Zoropsis as part of a long-running research project to study how the spider species is settling down in the Bay Area. \n\nThey ask anyone who spots something that looks like Zoropsis around the house to avoid the temptation to squish it. Rather, let them know about the sighting by e-mailing a description of the creature to dubick@calacademy.org. A digital photo of the spider is even more helpful, Griswold said."\n\n\nThis is NOT a brown recluse. A brown recluse has a fiddle shape on is back as you can see here: http://z.about.com/d/p/440/e/f/19570.jpg See how there is a brown tiny little violin/fiddle shape on it?\n\nAlso, the recluse has a distinctive eye pattern; "A more definitive diagnostic feature is the eye pattern -- brown recluses have a semi-circular arrangement of 6 eyes in 3 groups of 2 while most other spiders have 8 eyes."\n\nhttp://www.uky.edu/Ag/Entomology/entfacts/struct/ef631.htm\n\nEdit Note: Member bo_fra did not have the Zoropsis spinimana listed in their list of possibilities until after I posted this answer. I went over every single post with a fine toothed comb to see if anyone mentioned the Zoropsis spinimana to make sure I was not duplicating someone else's effort if the answer had been found. The Zoropsis spinimana and one of the links I posted with this answer appeared in bo_fra's altered answer after I'd posted my own. I also posted on the Flicker account as "weheartjon" at ten to 7pm central time. Since there are no time stamps, anyone who posted before me can copy the answer I posted and pose it as their own original answer when that is not the case. The name of the spider isn't exactly common and stands right out. Plus everything else on his list are simple spider names, not specific species names. Also a clue is the Spinimana was added to the bottom of the list and he took one of my links. All for a few silly points. At least Google Answers pays real money so there isn't juvenile sniping. It would be nice if people were honest.
72376
Spiders are so ugly because they are arachnids! They have 8 legs and are meant to creep you out! But they are the only reason in which this planet is not been taken over by all them dumb bugs and instects!
1125168
clipped from www.wisegeek.com\n\nFor sheer length you can't beat a female Giant Walking Stick (Phobaeticus serratipes). Found in Malaysia and Singapore, looking like an assemblage of twigs, it is perfectly camouflaged among the branches where it lives. The longest specimen on record was an amazing 21.8" (55.5cm). Some people even keep these huge insects as pets.\n\nThe Giant Walking Stick may be long, but it doesn't have much mass. For that you have to turn to the giant scarab beetles. Among them, entomologists have settled on 5 contenders:\n\nThe South American Longhorn Beetle (Titanus giganteus) of French Guiana makes perhaps the most impressive showing with a body length over 6.5" (16.7cms).\n\nA shorter but far thicker competitor is the Acteon Beetle (Megasoma acteon) of South America. Males can grow to 5.3" (13.5cms) long by 1.6" (4cms) thick. \n\nThe Elephant Beetle (Megasoma elephas) found in Mexico and Venezuela has a shorter body than the Aceton, but a longer snout, making its total recorded length 5.4" (13.7cms).\n\nBringing up the rear are two species of Goliathus: regius and goliatus, both measuring in at 4.3" (11cms).\n\nIn 1874 the Rev. J. G. Wood published Insects Abroad, in which he claimed to have in his possession a 9" (22.8cm) South American Longhorn Beetle (Titanus). A specimen this large has never been documented since, and no one is quite sure what method he used to measure the bug. Therefore the accepted recorded length remains at 6.5" (16.7cms), which still leads the top five contenders.\n\nAlthough the Giant Walking Stick and scarab beetles win for length and mass, for sheer weight you'll have to turn to the giant wetas (Deinacrida heteracantha) of New Zealand. A pregnant female can top the scales at over 2 ounces (71gms)! \n\nThere are well over 1 million insect species known, with an estimated 10 million still undocumented. However, the title of world's biggest insect remains a matter of what constitutes "biggest" to you: length, mass or weight!
606149
I was going to say pseudo-scorpion, a very common arachnid related to scorpions and spiders, but with no tail stinger, but then I saw the size in your details.\n\nThe only critter I can think of in North America that could possibly be that large is one of the types of crayfish.\n\nHere is a site with some pretty good crayfish pictures: http://www.shrimpcrabsandcrayfish.co.uk/Shrimp.htm?crayfishamerica.html~mainFrame\n\nIf you were in more tropical climes, I would guess that it might be some form of crab, such as a land crab or robber crab.
240237
1.  Spiders\n2.  Spiders\n3.  You'll never guess!
311259
"Britain has more than 600 species of spiders, all of them harmless to man."\n\nPretty difficult to list them all here - but the links below should help.