132 WASPS AND THEIR WAYS 



sheets, but in the form of shell-work, or 

 overlapping scales. Such nests generally 

 have several entrance holes and are often 

 very handsome structures. 



As a rule the nests built by yellow-jack- 

 ets in the ground have coverings of coarser 

 material and less elegant architecture than 

 nests built in trees or under roofs. But 

 even where the nest is in the ground, it 

 has its covering of paper walls. Certain 

 species of yellow-jackets, or ground-wasps, 

 as they are often called, take possession of 

 a hole they find, and this they enlarge to 

 suit their needs by biting off^ and carrying 

 out, bit by bit, the earth. They are cave- 

 dwellers, but their caves are made warm 

 and comfortable by the paper lining they 

 always give them. It is quite a surprise to 

 dig out one of these nests for the first 

 time and find the snug and complete habit- 

 ation, often of quite large size, and fitted 

 up with its tiers of combs and all the 

 essential parts of an out-door nest. 



