order.opiliones

Evil asked me about my daddy longlegs comment yesterday. The curious creatures guy told us that they are not really spiders, and Evil asked what they were. I did some research, and have some answers. Here we go.
First of all, there are two different creatures that are referred to as daddy longlegs. The "real" daddy longlegs live until logs and rocks, and apparently aren't often seen. The little guys that we call daddy longlegs are actually cellar spiders, but are so often confused with daddy longlegs that spider guys now refer to them as "daddy longlegs spiders" to differentiate from the real daddy longlegs.
Now on to the technical differences. Arachnida is a main animal category, and there are different subgroups (orders) within this category. Spiders are in the "order araneae", scorpions are in the "order scorpiones" and mites and ticks are in the "order acari". Daddy-longlegs are in their own separate subgroup of arachnida called "order opiliones". They have one main body segment onto which all eight legs are attached, and they only have two eyes. The main difference is that they don't make silk, and therefore don't hang out in webs unless they're being eaten by a spider. Daddy longlegs spiders are spiders, and therefore have two main body segments, eight legs attached to the front segment, eight eyes clumped together in the front of the body, and produce silk and webs. So really, the things you think of when you hear daddy longlegs are actually spiders, but the real daddy longlegs are not.
How's that for an answer Evil?

**I think that I must live under a log or rock, because the "real" daddy longlegs (the top picture) are what I think of when I hear "daddy longlegs". I don't recall seeing this "daddy longlegs spider" guy at all. He's kind of ugly.