HYMENOPTERA 



971 



In digging the burrow and in tearing down the turret the earth is 

 softened with water, which the wasp brings in her mouth from some 

 pool or stream - 



Not all species of Odynerus mine in the ground; many burrow in 

 the stems of pithy plants, making a series of cells separated by parti- 

 tions of mud ; other species will avail themselves of any convenient 

 cavity in which to make their nest, frequently utilizing the deserted 

 nests of the sphecoid-wasps known as mud-daubers. In this case a 



Fig. ii86.—Eumenes fraterntis and its nests. 



single cell of a mud-dauber is divided by a transverse partition, mak- 

 ing two cells for the smaller Odynerus . One year these wasps plastered 

 up many of the keyholes in our house, including those in bureaus. 



Some species of Odynerus are masons constructing nests entirely 

 of mud. One of our species, Odynertts birenimaculdtus, makes a nest 

 about the size of a hen's egg. This is composed of hard clay, fastened 

 to a twig of a bush, and contains many cells. 



The jug-builders, Eumenes. — The 

 wasps of the typical genus of this sub- 

 family are potter-wasps which build nests 

 that appear like miniature water-jugs. 

 The nests of our common species, Eumenes 

 fraterntis, are often found attached to 

 twigs (Fig. 1 1 86). In this genus the ab- 

 domen of the adult is petiolate. These 

 wasps provision their nests with cater- 

 pillars and frequently with cankerworms. 

 Fabre, who studied the habits of a 

 European species of Eumenes observed 

 what goes on within the nest by making a window in the side of it. 

 The egg is suspended from the ceiling of the nest by a slender thread; 



Fig. 1 187. 



ridens. 



-Monobia quad- 



