HYMENOPTERA 151 



99. Sphecoidea. The Digger-wasps include a considerable 

 number of families. They have similar food and nesting 

 habits. All are solitary, most forms are miners and con- 

 struct their nests in the ground but some live in the stems 

 of plants. 



Nests of digger-wasps are provisioned with insects or with 

 spiders, which have been stung by the wasps until they 



FIG. 112. Hornets and their Nest. 



are in a comatose condition. They live until the larvae 

 are ready to use them as food. In this manner fresh 

 food is provided. One family of these wasps preys almost 

 exclusively on spiders; others prefer different kinds of 

 insects; one large species captures cicadas or harvest-flies 

 and is known as the cicada-killer. 



To the digger-wasp family belong the Mud-daubers or 

 Mud-wasps and the Thread-waisted Wasps, also usually 

 mud-masons. Their nests, in and near houses, especially in . 

 chimneys, are well known to all. 



