68 GENERAL ZOOLOGY 



From the time the workers take up the tasks of the nest 

 the female is left free to devote all her energies to laying 

 eggs, and the nest is rapidly made larger by the workers. 

 Toward September males and females appear from the cells, 

 which up to this time have produced only workers. The males 

 die soon after mating. On the approach of cold weather, the 

 workers also die, and only females remain to hibernate and 

 begin a new nest the next spring. 



Another type of nest, in which the horizontal layers are 

 inclosed in a thin envelope, is made by the somewhat larger 

 and stouter-bodied wasps (Ves'pa, Fig. 45) commonly known as 

 " hornets." These wasps are generally conspicuously marked 

 with yellow, and their nests may be a foot and a half in 

 diameter. 



The social wasps are the original paper-makers of the world. 

 The first suggestion as to the manufacture of paper by man 

 may have come from watching the work of these insects, 

 though the necessary steps may well have been taken without 

 such suggestion, as the use of the leaves of palms and the 

 bark of several trees is still common in China and India. It 

 is interesting to note that though the wasps were the original 

 inventors of paper, they have, in some cases, learned to take 

 advantage of man's present greater facilities for its manufac- 

 ture, thus saving themselves the trouble. In one case in 

 Missouri the wasps found the damp paper of bags, which 

 had been tied over grape-clusters in a vineyard to keep out 

 injurious insects, so much to their liking that they used it 

 freely instead of their own wood-pulp paper. 



Solitary Wasps. Those wasps which are solitary in habit 

 make nests in various situations and of different materials, 

 and store them with food, generally insects and spiders, which 

 they often sting so as to paralyze but not to kill them. Each 

 species has its own method of providing food, and each keeps 

 pretty closely to the same material for nest-building. Thus 



