• Arachnida Spiders have just two body parts, a cephalothorax and an abdomen. In spiders, these two body regions join at a narrow waist, called a pedicel. The abdomen is soft and unsegmented, while the cephalothorax is harder and includes the eight legs that characterize spiders.Members of the order Araneae prey on other organisms, usually insects. However, spiders can only consume liquids, as they lack chewing mouthparts. They use chelicerae, pointed appendages at the front of the cephalothorax, to grasp prey and inject venom. Digestive juices break the food down into liquid, which can then be injested by the spider. Most spiders have eight simple eyes, although some have less or even none at all. When trying to identify a spider, observing the number and arrangement of the eyes is an important detail to note.