Wikipedia:WikiProject Fact and Reference Check/Example 2/
From the article on Spiders.
Spiders are invertebrate animals that produce silk, have eight legs and no wings . More precisely, a spider is any member of the arachnid order Araneae, an order divided into three sub-orders in newer systems: the Mygalomorphae (the primitive spiders), the Araneomorphae (the modern spiders) and the Mesothelae, which contains the Family Liphistiidae, rarely seen burrowing spiders from Asia. The study of spiders is known as arachnology, although it is often grouped under the more general area of entomology.
Many spiders hunt by building webs to trap insects. These webs are made of spider silk, a thin, strong protein strand extruded by the spider from spinnerets on the end of the abdomen. All spiders produce silk, although not all use it to spin elaborate traps. Silk can be used to aid in climbing, forming smooth walls for burrows, cocooning prey, and for many other applications.