THEODORE H. PRISON 147 



tubes make it difficult for the clumsy parasitic ^Icloid beetles 

 to climb about the cells, and Kellogg says they prevent the 

 "flooding of the open burrows by water." Walsh says the 

 tubes serve to keep out parasites. If the tubes served in any 

 way as a protection to the real entrance to the burrows of 

 Anihophora abrupta, why is there this break in their continuity, 

 especially upon the upper portion? Water could certainly gain 

 entrance here and the rift is large enough to enable several of 

 the smaller hymenopterous parasites to enter the tube. Fur- 

 thermore, as the chinmeys are open at the outer end I fail to 

 see in them any effective barrier to the inroads of parasites. 

 Emphor fuscojubatiis, according to Grossbeck, builds little 

 turrets one-half inch high around the entrance to the burrows 

 and then drops the remainder of the pellets over the rim. 



Watching the bees at their labors, I soon saw that the tube 

 was formed by pellets of clay brought out from the burrows by 

 the bees when engaged in their mining operations. After 

 being in the l)urrows a short time the Ijees back out and carry 

 with them, under the body, a sinall amount of wet clay. This 

 explains why the bees were lapping up moisture when I first 

 came across and followed them to their burrows in 1917. The 

 bees go to a place where water is to be had and when they have 

 lapped up all they can hold return to their burrows. Then 

 they use the water to soften the hard clay in which they dig 

 their burrows. If such is not the case how are we to explain 

 the fact that the bees remove wet clay fro"(n burrows made in 

 a hard dry clay bank? An interesting manner of obtaining 

 water to use in their mining operations has been observed in 

 the case of Emphor fuscojubatus. Grossbeck reports seeing 

 adults of this species on the surface of roadside puddles, ])ut was 

 not sure they actually lapped up any of the water. Knab 

 (1911) has observed Emphor bombiforniis alighting on the surface 

 of water and actually saw them lapping up the water. Nichols 

 records the same curious habit for Emphor fuscojubatus, saying, 

 "numerous bees were discovered floating on the surface [of a 

 small pond] with legs outstretched, presumably sucking up into 

 their crops a supply of water for use in making the nest." 



Instead of simply dropping the clay from the entrance of the 

 burrows these bees instinctively make with it a cylindrical tube 



TRANS. AM. ENT. SOC, XLVHI. 



