The little crab spiders (Diaea and Xysticus) adapt their color to blend with that of their surroundings. These striking little spiders rest in the centres of flowers, where, waiting with outspread forelegs, they capture flower-visiting in-sects, usually bees, flies and butterflies. Upon a white blossom, the prevailing color will be a chalky white; on a yellow, its color, though pale, will tone sufficiently to render it inconspicuous; while upon a pink blossom its body will carry a pinkish flush. If a spider is removed from a flower of one color to that of another, its hue will change. The trans-formation is slow, definite, and sufficient to render it inconspicuous as it rests.

Wonder Book of Knowledge