2 MELANDER AND BRUES. 



depart in their habits from the strictly sohtary bees in that a 

 male and two or three females are generally necessary for the 

 successful direction of a single menage. Moreover, a large 

 number of nests are usually associated as a colony which may 

 be scattered over a considerable distance or so populous that the 

 tunnels almost intersect by their irregularities. The openings to 

 the nests, however, are always separated by a distance of two or 

 three inches or more. It can thus be readily seen that Halictus 

 lives under conditions more or less similar to those of their more 

 gregarious relatives, the ants, and hence it is not surprising that 

 they are forced to harbor the same class of guests, and to be 

 exposed to the same vicissitudes as are their cousins. 



In constructing their nests the bees dig by means of their 

 mandibles in the sandy clay, forming a hole of a diameter only 

 slightly greater than will admit the largest female. The wall is 

 then banked up with a plaster formed by the aid of saliva. Im- 

 mediately behind the entrance is a short blind passageway, only 

 large enough to allow a bee to turn on itself within. 



This niche, which is always less than an inch from the entrance, 

 serves simply to allow the bees to pass one another in the in- 

 terior of the nest. From this point the gallery extends nearly 

 straight back into the hill side, for a distance of a few inches and 

 then slopes downward to the end — a total length of a foot or 

 so. Near the further end jut a number of small diverticula 

 radially extending from the main tunnel. 



These are the nurseries of the young bees, where are stored the 

 pollen and honey which is destined to serve as food for the bee 

 larvje of the coming generation. The excavation of the tunnels 

 is a matter of considerable toil, requiring many days for its com- 

 pletion, but so industriously do the little bees work that at the 

 close of day a miniature mound of sand has accumulated on the 

 hill-slope below the opening. During the warm portions of the 

 day the site of each colony of nests is a scene of inspiring activ- 

 ity. The air is filled with an ever-changing swarm of bees, each 

 bent on its own task of excavation or of collecting honey and 

 pollen, while from the openings of completed nests others can be 

 seen peering about and eying everything that comes within their 

 range of perception. At night everything is quiet, the trespas- 



