Crab Spider on Yarrow. Notice the bug on its front right leg. This and the other two crab spiders shown in this gallery were in the meadow and two of them stayed on their respective plants for at least 3 days. If you're familiar with Yarrow, that will give you a good idea of how small these are. I would say, with their legs folded in, they would fit on a nickel, maybe even a dime.