Vol. xxiii] ENTOMOLOGICAL NEWS. 259 



As in Anthophora occidentalis, some of the tunnels were 

 not adorned with a clay device. It seems to us more rational 

 to consider these semi-tubes more for protection against pre- 

 daceous insects or parasites (as Bombyliid flies, which we do 

 not imagine would as readily discover the lateral entrance to 

 the Melitoma burrow as they would an unprotected face tun- 

 nel), than for shelter against moisture. The Hymenoptera 

 of the plains are very much subject to the attacks of parasites. 

 The fact that some clay tubes constructed by Hymenoptera, 

 notably Odyncnis, are often quite vertical would not favor 

 the "protection against moisture theory," though they would 

 offer considerable relief against dust and sand. 



Anthophora occidentalis Cresson. 



Anthophora occidentalis, the "Larger Tube-Building Cliff 

 Bee," is a stout-bodied solitary bee found in large colonies in- 

 habiting clay cliffs. Their tunnels are three-eighths inch in di- 

 ameter and extend into the bank about eight inches where they 

 end in several cells. These cells are provisioned with pollen 

 and are so made that when dug out they came from the gallery 

 as separate urn-shaped clay nodules of uniform size. (PI. XV, 



% 3)- 



The entrance of the tunnel is protected by a curved clay tube 



of from three-fourths to two inches in length. (PI. XV, figs. I 

 & 2). These tubes bend downwards and very often the top 

 or outer curve is split longitudinally, (probably sun cracked) 

 making the tube resemble the moulted skin of a Cicada as it 

 hangs on a tree trunk. Where the tubes were absent from the 

 tunnels, as was often the case, it appeared to be a matter of 

 accident. Viewing the face of a cliff in which there was a 

 colony of these bees, the unprotected hqles were the only 

 marks of its presence, the ones protected by the tubes being 

 not at all conspicuous. This may or may not be the reason for 

 the tubes. 



As to the life history of these bees, each female has her 

 own burrow. The egg is laid in a cell provisioned with pollen. 

 We found larvae and pupae in cells, June 2Oth. It was in colo- 



