White-banded Crab Spider (Misumenoides formosipes)

I found the yellow-form of this spider on Oenothera biennis at a disturbed forest edge. I accidentally knocked it off of the plant but returned it to the flower promptly!

Females of species have the ability to change color (between yellow and white) to match their hunting grounds (usually flowers). This proves really helpful in ambushing prey and avoiding predators. The process of changing colors can take up to three weeks, and the energetic cost for spiders making these changes can be quite high.