|Cobweb Spider - Theridion sp.|
Family Theridiidae - Cobweb Spiders, Scaffold Web Spiders, Comb-footed Spiders
Female spider photographed in the wild at Chicago, Illinois. Size = 6mm
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Cobweb spiders spin an irregular web that can be described as an intersecting mass of scaffold work with a central area consisting of a three-dimensional trellis of silk. The common name "comb-footed spider" results from the "comb" on their last pair of legs. The comb is a series of serrated spines which they use to comb out the silk from the spinnerets. This combed silk is not sticky but insects get entangled in it. The black widow spider is a member of this family. 
Common in North America, cobweb spiders be found almost anywhere there are weeds, fences, trees, walls, or other upright structures to build their webs. They will eat almost anything that is small enough to get trapped in their webs. Like most web-building spiders, cobweb spiders tend to have poor vision - they don't need to see very well because they can "feel" prey when it gets caught in their webs. Most cobweb spiders are considered beneficial to humans. They eat flies, mosquitoes, and other annoying creatures.
Cobweb spiders have eight eyes, eight legs, 2 body parts, and fang-like mouthparts called chelicerae. Cobweb spiders undergo simple metamorphosis: like all spiders, young cobweb spiders hatch from eggs and look like tiny adults. They shed their skin as they grow. Most cobweb spiders live for less than 1 year. At the end of the summer, females produce a large amount of eggs that they wrap in a papery egg sac made of silk. Spiderlings hatch in the spring.
Female cobweb spider and egg cases. Each papery case contains dozens of eggs. Parasteatoda tepidariorum
Class Arachnida / Order Araneae: Spiders are the largest group of arachnids. They are easily recognized by their eight legs, and there are few creatures great or small that elicit such irrational fear in mankind. The vast majority of spiders are completely harmless and offer beneficial services, chief of which is keeping the burgeoning insect population in check. I am continually amazed at the resourcefulness of these supremely successful predators.
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