392 ENTOMOLOGICAL NEWS [Nov., '13 



Some Observations on Mud Wasps (Hymen.). 



By Phil Rau and Nellie Rau, St. Louis, Missouri. 

 A Wasp and Her Spiders. 



A Pelopoeus* was building her nest on the wall of the 

 room behind a dark curtain, and about five feet from the 

 floor. I came in time, 5 P. M., June 23, to see her seal up the 

 first cell. By 1.30 the next day the second cell was three- 

 quarters done, and by 10 o'clock the following morning it too 

 had been completed and sealed. For five hours I watched for 

 this builder to return to add the third cell, but it was not un- 

 til 3.55 that she returned, bringing a pellet of mud. She 

 alighted upon a highly-colored cover of one of the current 

 magazines which lay on a soap-box by the wall. From this 

 landing she walked slowly but directly to the wall and then 

 straight up the wall for about 12 inches until exactly even 

 with the nest, then taking a horizontal course she walked 

 toward the nest, but when about 6 inches from it she hesitated, 

 made a circle of perhaps ij4 inches, hesitated again for a 

 few seconds, then flew directly to the nest, made her deposit 

 and immediately flew out again. 



I removed the colored magazine cover upon which she had 

 alighted when entering, thinking to confuse her. She re- 

 turned after an absence of 30 minutes, but did not seem to 

 miss her landmark, for when this was gone she alighted on 

 the wall and went directly to the nest as before. By 4 

 o'clock the third cell was completed and the wasp was busy 

 in carrying in spiders. While she was out hunting I removed 

 four spiders from the nest of another wasp. They had the 

 appearance of having been newly paralyzed. These I added 

 to those already in the cell in order to find out whether the 

 mother wasp could or could not recognize foreign prey. She 

 returned with one spider, the booty of a half-hour's hunt, and 

 flew to the nest with no difficulty, entered the cell, but left 

 it immediately, buzzed around the room in one large circle 

 and then back to the nest again, removed one of my spiders 



* Sceliphron {Pelopoeus ) caementarium. 



