Pollen Sacs. 283:365

"Just like us, the bee’s legs have a tibia, which is the lower leg . On Bumble bees for example, the tibia is flat, somewhat convex, shiny and surrounded by hairs, some of which are rather long and stiff. This forms what is called the pollen basket. Located at the lower end of the tibia is a comb-like structure, and on the metatarsus is the press. These two structures work together like levers.

 

The pollen (which has been moistened with nectar to make it sticky) is transferred to the press and the bee manipulates the press and comb to press the pollen onto the bottom part of the flattened tibia. Each new batch of pollen is pressed onto the bottom of the Pollen Sac, pushing the previous batches further up.

 

When the Pollen Sac or basket is full, it will bulge with upwards of one million grains of pollen. The hairs that surround the tibia hold the pollen in place while the bee flies from place to place, either collecting more pollen, drinking nectar, or flying back home to stock the nest with this carefully gathered food, which is what

the offspring will eat when they hatch."

~ From gardeningforwildlife.com

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