PLATE 2.30. WORKER POLLEN PRESS

RIGHT Photomontage of the metathoracic (hind) leg and its medial surface. From top to bottom are the tibia, basitarsus, and four short tarsal segments. Between the tibia and basitarsus is the flattened, notched pollen press. The ranks of hairs act as combs for grooming and pollen gathering. When the basitarsal combs are loaded to capacity with pollen, the rastellum (rake) is used to unload the comb by scraping it into the press where the pollen is compressed and transferred to the tibial baskets on the outside surface above the pollen press. Hence, pollen groomed from the right side of the body is combed from the inner surfaces of the middle and forelegs by the left hind leg, from which it is removed by the right rastelhun for deposition in the pollen basket of the same leg. The opposite sequence is used for the left side. ( x 47)

MIDDLE LEFT Mediolateral view, of the pollen press. The floor of the press is edged with fine hairs, and its surface is covered with denticlelike cuticular spines or scales. Long, curved hairs from the tibia bend down and lie over the press and a picket of shorter, stiff spines (rastellum) lines the dorsomedial margin of the press. Small mechanoreceptor hairs are visible at the leading edge of the spatulate hairs (upper left). (x 100)

TOP LEFT Hairs on the medial surface of the tibia. The flattened-tip spatulate character of these hairs contrasts markedly with the basitarsal hairs, which have serrated edges and a fairly sharp tip. The specialized hairs of the tibia may have an important function in the process of gathering and packing pollen (see Plate 2.31). (x 560)

BOTTOM LEFT Higher magnification of the sharp cuticular spines (spicules) that line the floor of the pollen press and the finer hairs that form a fringe around the press. (x 400)