MINERS 27 



Bees of the genus Colletes dig burrows often 

 eight or ten inches deep. Although solitary bees 

 in the sense that each sinks her own shaft and 

 provisions only her own cells, yet they are gregarious, 

 large numbers of them mining into one small area. 

 Sometimes it is a clay- bank, a vertical face of 

 weathered sandstone, or the mortar between the 

 masonry of an old wall. The shafts are filled with 

 a succession of cells in line from two to eight 

 each provisioned with a paste of pollen kneaded up 

 with honey. The cells themselves are formed by a 

 secretion from the bee's mouth, which dries and 

 hardens into a film much like gold-beater's skin. 

 Three or four layers of this delicate substance can 

 be separated with care from each cell more from 

 the ends. When the last cell is completed the 

 shaft is closed with grains of sand or earth. Panur- 

 gus, of which we have two species, sinks vertical 

 shafts, each containing six cells. 



Eucera longicornis, whose male is notable for the 

 length of its antennae as long as its body fre- 

 quents loamy and sandy soils, and sinks a shaft 

 six or eight inches deep. At its termination it 

 hollows out an oval cell, and apparently treats the 

 walls with its saliva to prevent the absorption of 

 the mixture of pollen and honey that is stored for 

 the grub. Like Colletes it is gregarious in some 

 localities, though not in all. Three of our species 

 of Anthophora likewise mine in the ground, but the 

 other is a carpenter and mines into wood. The 

 former from the main shaft of their mine construct 



