'I'WO I'O'I ri.K WASPS 381 



loiii^' and narrow \y\n\ not only ('\))lains wliy tlic larva spins 

 its flat and ()^■al cocoon, but also why the pai'cnt was]) rc- 

 (luircs these o'lohnlar nursei'ies i'or her oft's])rin<>-. 



Here I ninst droj) the history of the red EumcncH. Al- 

 though her rows of i)ots were everywhere about the walls 

 and timbers of Kalacoon Laboratory, oidy one or two were 

 occupied duriiiL'" the five months of our stay. The remainder 

 were old ones from whii'h tbe wasps had issued. From the 

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

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

 where between the months of Se])teniber and February. 



The smaller pottci', the buff Eumcncs, nests in March, 

 eonstructni"- 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. ^lany stones and bits of hard material project 

 from tlie 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 arowinij nursery that save for its darker color, due to 

 moisture, the new work could not be distinguished from the 

 old. 



A tliorough inspection of her work takes place after 

 every load of clay is incorporated in the nest. Ervery 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 



