. Animal biology. Biology; Zoology; Physiology. ORGANIC ADAPTATION 333 son glands Levers to move barb ter of the surface automatically determines whether claw or pul- villus shall be used. But there is another adaptation equally re- markable. "The pulvillus is carried folded in the middle, but opens out when applied to a surface; for it has at its upper part an elastic and curved rod, which straightens as the pulvillus is pressed down. The flattened-out pulvillus thus holds strongly while pulled along the surface by the weight of the Bee, but comes up at once if lifted and rolled off from
. Animal biology. Biology; Zoology; Physiology. ORGANIC ADAPTATION 333 son glands Levers to move barb ter of the surface automatically determines whether claw or pul- villus shall be used. But there is another adaptation equally re- markable. "The pulvillus is carried folded in the middle, but opens out when applied to a surface; for it has at its upper part an elastic and curved rod, which straightens as the pulvillus is pressed down. The flattened-out pulvillus thus holds strongly while pulled along the surface by the weight of the Bee, but comes up at once if lifted and rolled off from its opposite sides, just as we should pull a wet postage stamp from an enve- lope. The Bee, then, is held securely till it attempts to lift the leg, when it is freed at once; and, by this exquisite yet simple plan, it can fix and release each foot at least twenty times per ; (Fig. 217.) The characteristic struc- tures of the middle (meso- thoracic) legs of the Bee are a small pollen brush and a long spine, or pollen spur. The METATHORACIC LEGS exhibit four remarkable adaptations to the needs of the insect, known as the POLLEN COMBS, PECTEN, auricle, and pollen basket. The pollen combs comprise a series of rows of bristle-like hairs on the inner surface of the first segment of the tarsus: the pecten is a series of spines on the distal end of the tibia which is opposed by a concavity, the auricle, on the proximal end of the tarsal segment; while the pollen basket is formed by a depression on the outer surface of the tibia which is arched over by rows of long curved bristles arising from its edges. Thus the worker is fully equipped. Flying from flower to flower, the Bee brushes against the anthers laden with pollen, some of which adheres to the hairs on its body and legs. While still in. Sheath Palpus of sting Barb Fig. 218. — Sting of a worker Honey Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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