TWO POTTER WASPS 377 



ing in an open sunny trail or fashioned about a stem of razor 

 grass, which swings here and there in the breeze. Like the 

 finished jugs of the larger species, they are supplied with a 

 flaring lip, but the neck is very short in fact, negligible. 



But let us return to the first mentioned wasp the fin- 

 ished artist. This wasp requires one day to complete a single 

 jug. That is to say, she does the actual building in four 

 hours, but the remainder of the day must pass before pro- 

 visions may be stored, in order that the storeroom may be 

 perfectly dry. In building, the insect approaches the site, 

 carrying a pellet of mud in her mandibles. At first she re- 

 mains suspended in the air some two feet from the scene of 

 operations. Now she flies here and there, up and down, to 

 this side and that, always with her head towards the nest. 

 Gradually she works up to it until an inch or less away. 

 Here she suspends herself once more for a few seconds before 

 finally alighting directly upon the building site. 



The pellet is placed upon the surface and shaped into 

 a tiny ring, one or two millimeters in height. From this 

 foundation the remainder of the jug is constructed. After 

 this initial ring or foundation is in place, the fresh pellet 

 is always deposited on its inner surface, and after being 

 somewhat flattened is modelled into a section of wall by the 

 wasp's mandibles on the inside and her fore-legs on the out- 

 side. The method is as though one were modeling a minia- 

 ture bowl between the thumb and fore-finger. 



Each jug serves as a nursery for a single wasplet and 

 is provisioned with ten span-worms. They are prepared by 

 the wasp either by being stung into paralysis or what is more 

 likely, are slightly crushed from end to end by the wasp's 

 mandibles. The nervous system of the caterpillar is spread 

 out through its numerous segments and would therefore be 

 difficult for the wasp to reach adequately with her sting. I 

 have seen a wasp alight with her prey and proceed to mouth 

 it roughly in a dozen different places, but her sting was never 

 brought into use. Further, the caterpillars are capable of 



