Spiders are members of the animal kingdom. They also belong to the phylum Arthropoda, together with crustaceans, insects, millipedes, centipedes, and other animals with distinctly segmented bodies (but not worms). Spiders share the class Arachnida with mites, ticks, scorpions, harvestmen (“daddy longlegs”), and other animals with eight legs. It is important to also know what spiders are not. They are not insects or “bugs,” even though they are distantly related.