Harvestmen . . . AKA Daddy Longlegs . . . are arachnids, but they are not spiders. Kind of like ants are insects but not dragonflies. Harvestmen have one body section and spiders have two). They have only two eyes and spiders have eight. They have a segmented abdomen and spiders don't. They don't make webs, silk, venom . . . and . . . surprise, surprise . . . . they don't all have long legs.
These are some photos I took of one I happened by. Cool beans!