HYMENOPTERA. 175 



resembling the Sphecina closely in habits, but differing 

 from them greatly in structure ; and it is on this structural 

 basis that they are classed with the Vespina, although 

 they are solitary wasps. 



Others of the Eumenidse build a series of cells in 

 the pith of some plant, burrow into the ground, or use 

 burrows dug by some other wasp or by some different 

 kind of insect. Most of them store their burrows with 

 caterpillars; one species uses the saw-fly entirely as food 

 for its young. Outside the Eumenidae, the majority of 

 the Vespina build their nests of paper. This paper they 

 make out of old bark or wood chewed to a pulp and mixed 

 with the saliva of the wasp -workers. Occasionally shreds 

 of leaves cast up by the water's edge are utilized, and this 

 material seems to make a paper even stronger than the 

 usual material. 



