LIFE-HISTORY OF BOMBUS 2% 



surface with orange, showing where the metatarsus 

 of the middle leg, which bore orange pollen grains, 

 had patted it. 



The same organs are present in the hind-leg of 

 the humble-bee (see Fig. 5). 1 



To test the working of the apparatus I placed 

 some pollen in the receiver of a leg of a dead 

 queen of B. lafiidarius, and then straightened the 

 leg ; the pollen was at once transferred to the 

 corbicula. 



When the pollen is being collected it always 

 begins to gather at the lower end of the corbicula, 

 and the reason is now clear. Also the smooth and 

 slippery surface of the corbicula is explained, for the 

 pollen slides up it, as the result of the numerous 

 little contributions delivered on to it by the auricle. 



The few hairs that obstruct the entrance to the 

 corbicula number about three ; they stand a little 

 distance inside the entrance and are widely separated 

 from one another. They provide a means of 

 attachment for the pollen until the accumulated 

 mass has grown large enough to be supported by 

 the hairs at the sides of the corbicula. The edge of 

 the entrance to the corbicula is densely clothed with 

 fluff (seen under the microscope to be moss-like 

 hairs), which probably serves the same purpose. 



The surface of the receiver is smooth except 



1 In the honey-bee the bristles in the brush of the hind metatarsi are 

 arranged in ten transverse rows, and are about as wide apart as the tips of 

 the teeth of the tibial comb, but in the humble-bee they are not arranged in 

 rows. In many pollen-collecting humble-bees the brush contains only a little 

 dry pollen, and the moisture is confined to its upper corner, which is probably 

 the only part that is much combed by the tibia. 



