Wikipedia:WikiProject Fact and Reference Check/Proposal 2

Spiders are invertebrate animals1 that produce silk2, have eight legs3 and no wings 4. More precisely, a spider is any member of the arachnid order Araneae5, 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 6. 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 insects7. These webs are made of spider silk, a thin, strong protein strand extruded by the spider from spinnerets on the end of the abdomen8. All spiders produce silk, although not all use it to spin elaborate traps9. Silk can be used to aid in climbing, forming smooth walls for burrows, cocooning prey, and for many other applications.10

Fact and reference check
1 Statement: "Spiders are invertebrate animals" 2 Statement: "that produce silk" 3 Statement: "have eight legs" 4 Statement: "no wings" 5 Statement: "a spider is any member of the arachnid order Araneae" 6 Statement: "spider silk, a thin, strong protein strand"
 * "Arthropods include insects, crustaceans, and arachnids, such as spiders". Encyclopedia Article: Invertebrate. Microsoft Encarta Encyclopedia 2003.
 * "Invertebrate Zoology Section Spiders". Website: Milwaukee Public Museum
 * "Invertebrate Animals Arachnids" Mexico for Kids
 * "produce silken threads and webs" Encyclopedia Article: Spiders (Arthropod). Microsoft Encarta Encyclopedia 2003.
 * "spiders have eight legs" Encyclopedia Article: Spiders (Arthropod). Microsoft Encarta Encyclopedia 2003.
 * "they lack antennae and wings" Encyclopedia Article: Spiders (Arthropod). Microsoft Encarta Encyclopedia 2003.
 * "Spiders belong to the order Araneae" Encyclopedia Article: Spiders (Arthropod). Microsoft Encarta Encyclopedia 2003.
 * see: http://www.sciencenews.org/pages/sn_arc98/2_21_98/fob2.htm