TWO POTTER WASPS 381 



long and narrow type, not only explains why the larva spins 

 its flat and oval cocoon, but also why the parent wasp re- 

 quires these globular nurseries for her offspring. 



Here I must drop the history of the red Eumenes. Al- 

 though her rows of pots were everywhere about the walls 

 and timbers of Kalacoon Laboratory, only one or two were 

 occupied during the five months of our stay. The remainder 

 were old ones from which the wasps had issued. From the 

 abundance of old nests and the entire absence of their build- 

 ers, I concluded that their chief nesting season comes some- 

 where between the months of September and February. 



The smaller potter, the buff Eumenes, nests in March, 

 constructing from four to five cells of yellowish clay. They 

 are at first distinct, flattened jugs, shaped like an army wa- 

 ter canteen. Later as additional cells are added, placed here 

 and there at random, the individual jug loses its identity in 

 the mass of clay and the nest becomes a very commonplace 

 object. 



This wasp flies to a point some distance above her nest, 

 then in a spiral she descends with her burden. When build- 

 ing, this is a tiny pellet of clay which is deposited and very 

 carefully kneaded into proper shape by the wasp's head and 

 fore legs. Many stones and bits of hard material project 

 from the mortar of the nest, making it an impregnable re- 

 fuge for her young. She builds rapidly, every fifteen min- 

 utes, bringing a pellet, which is moulded so carefully into 

 the growing nursery that save for its darker color, due to 

 moisture, the new work could not be distinguished from the 

 old. 



A thorough inspection of her work takes place after 

 every load of clay is incorporated in the nest. Every scrap 

 of the edifice, the old as well as the new is gone over minute- 

 ly doubtless in search of flaws, however tiny, that might 

 afford an entrance for the ovipositor of the ever-ready para- 

 sites. Sometimes even the grass stem or whatever the nest 

 support may be, is likewise closely inspected both above and 





