164 C. H. TURNER. 



PROVISIONING THE NEST. 



The nests are stored with a black-headed, green, Hesperid larva, 

 which the wasp obtains from the neighboring field. These are 

 paralyzed and packed in the cell. The wasp carries the caterpillar 

 dorsal side down and head to the front. When she reaches the 

 burrow she pushes the caterpillar in ahead of her. Sometimes at 

 one stage and sometimes at another in the provisioning of the nest 

 the wasp folds her wings close to the body and backs into the nest 

 (Fig. 2, j), attaches her egg to the roof of the cell by means of a 

 cord about as long as the egg, and then comes out head first (Fig. 

 3, ?") and resumes her work. This statement is an assumption 

 based on the following facts : There is never found more than one 

 egg suspended from the top of a cell ; only once during the pro- 

 visioning of the cell does the wasp back in ; the attitude attained 

 by backing into the cell is the most favorable cne for attaching the 

 egg to the roof. When this lower cell has been filled, the wasp 

 fetches some water and then, out of the scrapings from the walls 

 of what is to be the next cell, she covers the first with a clay wall. 

 In most cases, after this partition has been formed, the second cell 

 is the right size for receiving the provisions ; occasionally the wasp 

 must remove a few pellets before storing it with caterpillars. 

 After it has been provisioned a mud cover is made for it out of 

 scrapings from the wall of the upper portion of the burrow. The 

 burrow is then closed with a plug of mud and dirt. The material 

 to form this plug is scraped from the rim of the burrow; as a 

 result the freshly formed burrow is topped with a saucer-like de- 

 pression. After a few days, or even a few hours, the wind, the 

 rain, and the pellet-dropping activities of other wasps obliterate the 

 depression. To obtain sufficient water for the softening of the 

 clay the wasp makes frequent trips to the near-by streamlet. Dur- 

 ing the whole time that the provisioning is progressing the burrow 

 remains wide open. The above account tallies with those of Isely 

 ('14, pp. 289-290) and the Raus ('18, p. 320). 



EXPERIMENTAL INTERFERENCE WITH THE PROVISIONING ACTIVI- 

 TIES OF WASPS. 



While the ivasp zvas in the nest arranging her provisions from 

 one to four caterpillars were dropped into th>? burrozu. Some of 



