The little shelves on the bees back legs where they move the collected items, typically, but not always, pollen are called Corbiculae, or more commonly known as "Pollen Baskets". Bees store nectar (soon to be honey) in a special organ called the honey stomach or crop. This is a secondary "stomach" that is more like a storage compartment than an actual digestive stomach. 
The "shelves" on the back legs of honey bees are called
pollen baskets, or corbiculae (singular: corbicula). These are specialized structures on the hind legs of female worker bees used for collecting and transporting pollen back to the hive. 
To use the pollen basket, a bee:
- Packs pollen from its body into a leg structure called a pollen comb. 
- Mixes the pollen with nectar or honey to create a moist pellet. 
- Transfers this pellet to the corbicula, which is a concave area on the outer surface of the tibia, framed by a fringe of stiff hairs that hold the pellet in place.  
This process allows a bee to carry a significant load of pollen, which serves as a vital protein source for the colony.