106 BEES AND WASPS [CH. 



grains are gathered by special brushes of hairs 

 situated upon the inner face of the first tarsal joint 

 (metatarsus) of the hind leg (vide fig. 17). These 

 brushes consist of nine transverse rows of stiff, closely 

 set hairs. When the brushes are fully laden with 

 pollen, the hind legs are crossed while the insect is in 

 flight (usually as it hovers in front of a flower), and 

 the pollen is combed out by certain spine-like hairs 

 that fringe the posterior margin of the tibia. The 

 outer surface of this section of the hind leg is some- 

 what hollowed and flattened, and its anterior edge is 

 furnished with rows of long curved hairs, so that the 

 outer face of the tibia forms, as it were, a basket 

 (the corbiculum), into which the pollen grains are 

 scraped. The middle pair of legs is then employed 

 to press the pollen firmly together in the basket, so 

 that it may be conveyed safely to the hive. On 

 arrival at the combs the bee pushes its hind legs into 

 a cell near the brood, and with a spur situated on the 

 apex of the tibia of the middle leg prises the pellet 

 of pollen out of the basket, and lets it fall into the 

 cell. Other bees then pack it down with their 

 mandibles. The hind legs of the "queen" bear none 

 of these modifications and are much less hairy; so 

 much so that the reddish-brown colour of the actual 

 leg is plainly visible, and affords an easy means of 

 detecting the " queen " when she is surrounded by a 

 throng of workers. The queen differs further in 



