BRANCH ARTHROPODS; CLASS IN SECT A : THE INSECTS 2*7 



the winter. In the spring she finds a deserted mouse's 

 nest or other hole in the ground, gathers a mass of pollen 

 and lays some eggs on it. The larvae, hatching, feed on 

 the pollen, dig out irregular cells for themselves in it, 

 pupate, and soon issue as workers, or infertile females. 

 These workers gather more pollen, the queen lays more 

 eggs, and several successive broods of workers are pro- 

 duced. Finally late in the summer a brood containing 

 males (drones) and fertile females (queens) is produced, 

 mating takes place, and then before winter all the workers 

 and drones and some of the queens die, leaving a few 

 fertilized queens to hibernate and establish new communi- 

 ties in the spring. 



The yellow-jackets and hornets (Vespidae), the so- 

 called social wasps, have a life-history very like that of 

 the bumblebees. The communities of the social wasps 

 are larger and their nests are often made above ground, 

 being composed of several combs one above the other 

 and all enclosed in a many-layered covering sac open 

 only by a small hole at the bottom. This kind of nest 

 hangs from the branch of a tree and is built of wasp-paper, 

 which is a pulp made from bits of old wood chewed 

 by the workers. The brood-cells are provisioned with 

 killed and chewed insects, the larvae of both solitary and 

 social wasps being given animal food, while the larvae 

 of both solitary and social bees are fed flower-pollen and 

 honey. As in the bumblebees, all the members of the 

 community except a few fertilized females die in the 

 autumn, the surviving queens founding new colonies in 

 the spring. The queen builds a miniature " hornet's 

 nest ' ' in the spring, lays an egg in each cell and stores 

 the cells with chewed insects. The first brood is com- 

 posed of workers, which enlarge the nest, get more food, 

 and relieve the queen of all labor except that of egg- 

 laying. More broods of workers follow until the fall 



