Pollen basket

The pollen basket or corbicula is part of the tibia on the hind legs of those four related lineages of apid bees that used to comprise the family Apidae; the honeybees, bumblebees, stingless bees, and orchid bees. A honeybee moistens the forelegs with a protruding tongue and brushes the pollen that has collected on head, body and forward appendages to the hind legs. First, the pollen is transferred to the pollen comb on the hind legs and then combed, pressed, compacted, and transferred to the outside surface of the tibia of the hind legs. There, the area of the tibia that - in most other bees - is the location of the scopa is a polished concavity surrounded by a fringe of hairs, into which the pollen is placed, and a single hair functions as a pin that secures the middle of the pollen load. Honey and or nectar is used to moisten the dry pollen. The mixing of the pollen with nectar or honey changes the color of the pollen. The color of the pollen can identify the pollen source.

Apparently, Karl von Frisch and other bee researchers have observed that individual honeybees are more or less efficient in packing pollen into the pollen basket. It takes an individual worker bee from three to eighteen minutes to complete a pollen load and return to the hive. Bees may collect both nectar and pollen. Some plants, such as poppy, are a source only of pollen.

Reference

 * Dorothy Hodges, The Pollen Loads of the Honeybee, published by Bee Research Association Limited, 1952