288 A BOOK OF INSECTS 



may persist for three or four years ; but at the first signs 

 of waning fertility she is deposed in favour of a youthful 

 successor. Thus the commonwealth of the hive endures. 



Some tropical wasps construct very durable nests, and 

 are known to store up food after the manner of bees; 

 while others are said to found new colonies by swarming. 

 The best-known species, however, resemble humble-bees 

 in the fact that their communities last only from spring to 

 autumn. Including the hornet, we have seven kinds of 

 social wasps in Britain, and these build in three different 

 ways. The two species of " common wasps " (Vespa vul- 

 garis and V. germauica), and that known as V. rufa, 

 inhabit subterranean chambers ; V. arborea, V. sylvestris, 

 and r. norvegica suspend their nests from the branches of 

 trees and shrubs; while the hornet {V. crabro) usually 

 builds above ground, but under cover, a favourite situa- 

 tion being a hollow tree, or beneath the thatched roof of a 

 cottage or outhouse. 



A queen of V. vulgaris, after hibernating, seeks out a 

 cavity from the roof of which at least one substantial root 

 protrudes. She then flies to a fence or gate-post, and 

 with her mandibles rasps away a bundle of wood-fibre. 

 This she macerates with her saliva, and thus works up a 

 kind of coarse brown paper which is the time-honoured 

 building material of her race. The first little pellet is 

 spread upon the root in the nest-hole. Hour after hour 

 the queen repeats her journeys, always returning with 

 another pellet which she adds carefully to the existing 

 evidence of her toil. In this way she constructs a short 

 triangular foot- stalk, attaches to it several cells, and shelters 

 them beneatli an umbrella-like canopy, which is subse- 

 quently enlarged to form a globular covering. In each 

 cell an egg is laid ; and when the grubs hatch the queen 

 assumes the role of nurse, although she continues to 



