THE HABITS OF EUMENES BELFRAGEI, CRESS 359 



The neck of the bottle is made quickly and with remarkable 

 deftness. A pellet of mud is applied to the edge of the hole 

 from which the neck is to be built up. Then, with the mandi- 

 bles on the inside and the tarsi on the outside of the nest, as 

 before, the neck is drawn up smooth and perfectly round, the 

 wasp imitating the effect of the potter's wheel by turning her- 

 self round and round as she draws the mud out into a tube. 

 The result is that the neck is a perfect cylinder. The rim or 

 flange is similarly made. The twenty-fourth load was placed 

 on the edge of the hole and pulled up to form the base of the 

 neck; the twenty-fifth load formed the remainder of the neck 

 and part of the rim; the twenty-sixth load completed the rim. 



The writer has wondered what the functions of the neck and 

 the rim of the cell could be. Neither is of use to the offspring, 

 for the next generation makes exit from the nest by gnawing 

 a circular hole through the wall. If of use at all, these struc- 

 tures must serve the adult wasp in the process of laying the 

 egg, storing the nest or plugging up the entrance. The rim 

 may serve the. wasp to hold on when it pushes the caterpillars 

 into the nest, and, indeed, may serve as a kind of funnel. It 

 would seem, too, that this entrance is more effectively closed 

 with mud when the whole work is completed. The writer is 

 inclined to believe, however, that the neck enables the wasp 

 to press more caterpillars into the nest without their falling 

 out than would be possible without it. 



After the rim was completed the wasp indicated the fact 

 that the nest building was over by flying away to a nearby 

 shrub and leisurely cleaning her legs and antennae. In a few 

 moments, however, she was back to the nest, climbed upon it 

 and protruded the abdomen as far as possible into the neck of 

 the nest (fig. 6). In this position she remained six minutes. The 

 egg was laid at this time. The egg is thus laid before the nest 

 is stored, as is true of all Eumenidae and probably of some 

 Sphecina, e.g., Monedula and Bembex, though the latter feed 

 their growing larvae from day to day. 



As stated above, the neck of the nest facilitates the pushing 

 in of the caterpillars. The capacity of the nest is surprising. 

 When the wasp brought the first caterpillar, the writer esti- 

 mated that the nest would hold seven or eight. After about 

 fifteen caterpillars had been brought in the observer actually 



