244 PHIL RAU 



Exp. 9. A Pelopoeus mother was carrying in spiders to fill 

 the twelfth cell of a handsome nest, but had not gone far with 

 the work when I added fourteen from the nest of another of the 

 same species. The wasp returned and at once emptied the cell 

 of my spiders and her own as well, and quietly stood guard 

 over the cell for fifteen minutes with an air of indecision, and 

 then flew away and was not seen again. 



Exp. 10. A one-celled Pelopoeus nest was built under a piece 

 of bark on a log beam in the old barn. I carefully removed this 

 bark, -filled the cell with borrowed spiders and replaced it. When 

 the wasp returned she had great difficulty in finding the nest. 

 After finally locating it she paused only a moment and dashed 

 away, and returning removed the spiders one by one. Since the 

 position of the nest was disturbed in gaining access to it, I should 

 have been surprised if she had not resented the intrusion, although 

 I cannot understand what caused her great confusion in locating 

 the nest when the alterations in the locality were imperceptible 

 to me. 



Exp. 11. A solitary cell contained five spiders when I added 

 six more from another nest. The wasp returned empty, put her 

 head into the cell and worked energetically for three minures, 

 either inspecting or packing them together or laying her egg. 

 Out she came at last and dashed away, but without a spider; 

 almost immediately she returned with her plaster and sealed 

 up the cell. 



When she had gone, I broke the seal and removed part of 

 the spiders which she and I had together supplied. She soon 

 returned with another pellet of mud for the seal, but when she 

 found it broken she alertly poked her head in, hastily withdrew 

 and flew away with the mud. After that she made four trips 

 from the nest, each time carrying out a spider which I had failed 

 to remove, but these four were of those which she personally 

 had put in. Then for ten minutes she thoroughly examined 

 the inside and outside of the cell, going in and out many times, 

 apparently in an earnest attempt to discover the cause of the 

 mysterious trouble. When I returned at four p. m. I found her 

 again filling this cell with spiders. 



During her absence I again meddled, inserting twelve spiders 

 from another nest. Returning she brought a spider which she 



