NESTING HABITS OF SOME ANTHIDIINE BEES. 267 



down of the work, nor cloudy or cool weather. The bee stopped 

 during weather conditions very favorable for work. 



In two instances, I have found the nests of some species ot 

 Anthidium in which the tunnel was unusually short, and over 

 and above which she had carried a mound of pebbles instead 

 of just filling even with the surface, as in the case of nests 

 having longer tunnels. In one instance 135 pebbles and in the 

 other 75 had been carried, more than enough to fill the tunnel (h). 



From our investigations it would seem that A . porter x will not 

 carry pebbles indefinitely even under ideal weather conditions. 



Whenever the cell becomes damp and mold develops, as some- 

 times after rain, the nest is deserted. 



Both males and females have been found resting in the dry 

 pods of yucca stems during rainy or cloudy weather, in cavities 

 in decayed wood or resting, perched bird-fashion on stems during 

 the night. 



During the day when the weather is fine the males dart from 

 flower to flower and are often seen hovering humming-bird 

 fashion in the air. Part of the day is spent in feeding and part 

 in searching for the female. He often darts upon the female 

 while she is working, copulation taking place on the ground. 

 The duration of this period is about 30 seconds. As yet we 

 have reared no parasites. 



SUMMARY. 



1. No females of Anthidium porterx have ever been found 

 digging a nest. 



2. On one occasion she drove away a nesting wasp, Odynerus 

 dorsalis, and used the nest for her own. 



3. The nests found in which the cells of the bee are placed 

 have in general been such as are made by wasps or other insects 

 nesting at the time. 



4. Anthidium porterx is solitary and is not found nesting in 

 close association as Dianthidium sayi and others. 



5. The cell is constructed of down and the tunnel above filled 

 to the surface of the ground, usually with pebbles. 



6. When the stones are removed artificially from the tunnel, 

 Anthidium porter % probably will not replace them indefinitely 

 even under ideal weather conditions. 



