USEFUL HYMENOPTERA. 



189 



and T? , workers which are unfertile females. The eggs are 

 not laid by the female immediately after fertilisation ; she 

 hibernates and commences the construction of a nest for a 

 new colony about April. From the spring until late in the 

 summer she lays her eggs in the regularly hexagonal, pris- 

 matic, horizontal cells of the nest. She is gradually joined 



Fig. 71. Hornet-injury to ash. 

 (Natural size.} 



ig. 72. Horuet-iujury to alder. 

 (Natural size.} 



in her labours by her progeny, of which first I? , then ? , and 

 lastly the stingless $ are produced. The latter die soon after 

 pairing. If by any accident the mother wasp should die 

 before any perfect females are produced, the whole colony 

 would become extinct. The duties of the J? are to continue 

 building the nest, to feed the helpless larvae, and to defend the 

 colony against enemies. The nests are covered with a paper- 



