NEW ARRANGEMENT OF BRITISH BEES. 
165 
and solitary. The only tangible characters the social 
tribes present to distinguish them from the solitary is 
the glabrous surface of the posterior tibiae, with their 
lateral edges fringed with bristles slightly curved in¬ 
wards, and which form, with the slightly indented sur¬ 
face of the limb, a sort of natural basket for the convey¬ 
ance of pollen or other stores to the nest. This, how¬ 
ever, has not been made use of as a main feature for 
scientific distribution, although they might follow the 
Dasygasters, as corbiculated bees, or little basket bearers, 
in which case they would form as pertinent a group as 
any of the rest, and the whole distribution of the bees, 
Apidee, would then rest upon the absence of, or the 
mode in which the polliniferous organs were present. 
But the wonderful attribute of their extraordinary in- 
«/ 
stinct prohibits their being treated with the rest in a 
consecutive line, and renders it rationally imperative 
that all the Cenobites should group together in a section 
by themselves, and separate from the rest. Therefore 
in my arrangement I have not availed myself of this 
very natural character, and here indicate it, to show that 
I have not passed it from not noticing it. 
Although the division into social and solitary yields in 
itself no tangible character whereby the insects may be 
separated, it being wholly empirical, yet is it so natural 
and necessary that it is impossible to gainsay it. We find 
the solitary section readily resolve itself into groups or 
subsections, determined by positive structural characters, 
indicative of certain habits, and having a conforming 
economy, besides which they are equivalents. 
Thus the first subsection presents us with the brush¬ 
legged Apidce ( Scopidipedes ), which collect pollen upon 
their posterior legs. These are further subdivided into 
