1 EP E-HISTORY’ OF SOMBUS 23 
surface with orange, showing where the metatarsus 
of the middle leg, 
had patted it. 
The same organs are present in the hind-leg of 
the humble-bee (see Fig. 5).’ 
To test the working of the apparatus I placed 
which bore orange pollen grains, 
some pollen in the receiver of a leg of a dead 
queen of Z. dapfidarius, and then straightened the 
lex; 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. 
