104 
BRITISH BEES. 
able, either from splendour, size, or remarkable eccen¬ 
tricities of structure, are numerous. Tropical and sub¬ 
tropical regions of course abound with them, in indivi¬ 
duals, in species, and in genera; and when we reflect upon 
the riches of the flora of those countries, which is per¬ 
petuated mainly by the agency of insects, amongst which, 
in fulfilling this indispensable demand, bees, as I have 
reiterated, are pre-eminently conspicuous, we shall not 
even wonder that their number, although excessive in 
the extreme, is considerably aided, in many cases, in 
the performance of this task, by peculiarities of structure. 
Thus, the splendid Brazilian genus Euylossa, although 
not conspicuous for size, is remarkably so for the enor¬ 
mous development of its posterior tibiae, which form 
very large triangles, compared wdth the size of the insect, 
deeply hollowed for the conveyance of pollen. Its 
tongue also, from the length of which the genus derives 
its name, is, when extended, more than twice the length 
of the body, and with which it is enabled to reach the 
nectarium, seated within the depths of the longest tubes 
of flowers. Other exotic bees, further to aid them in 
collecting pollen, in addition to the dense brushes with 
which their posterior legs are variously covered, have 
each individual hair of these thick brushes considerably 
thickened by hairs given off laterally, and in some cases 
these again ramify. Sometimes, in variation, the simple, 
single hairs have a spiral curve, which almost equally 
enlarges the activity of their operation. This is also the 
case with two very hairv-legged genera of our native 
bees, proximately allied to each other in the methodical 
arrangement, Dasypoda and Panurgus, the hair of whose • 
posterior legs have this spiral twist. The most hairv- 
legged exotic bees are essentially the genera Centris and 
