NEW ARRANGEMENT OP 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 tibise, 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, 

 Apidce, 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 (Scopulipedes) , which collect pollen upon 

 their posterior legs. These are further subdivided into 



