Although they belong to the class of arachnids, harvestmen - also known as daddy longlegs - are not spiders. The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax) are broadly joined, so that they appear to be one oval structure; they also have no venom or silk glands. They have a single pair of eyes in the middle of their heads, oriented sideways. Harvestmen are a scientifically neglected group.
As of 2006, over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. Seen at Mason Farm Nature Preserve.