328 ENTOMOLOGY 



BUMBLE BEES 



Familiar as the bumble bees are, their habits are but imper- 

 fectly known. The queen hibernates and in spring starts a 

 colony, utilizing frequently for this purpose the deserted nest 

 of a field mouse or sometimes the burrow of a mole or gopher. 

 The queen lays her eggs in a small mass of pollen mixed with 

 nectar (Putnam). The larvae eat out cavities in the mass of 

 food and when full grown spin silken cocoons, from which the 

 imago cuts its way out; the empty cocoon being subsequently 

 used as a receptacle for honey. At first only workers are 

 produced and they at once relieve the queen of the duties of 

 collecting nectar and pollen, caring for the young, etc. The 

 workers are of different sizes, the smaller ones being nurses 

 or builders and the larger ones foragers the kind commonly 

 seen out of doors. In the latter part of summer both males 

 and females are produced, but when severe frost arrives, the 

 old queen, the workers and the males succumb, leaving only 

 the young queens to survive the winter. 



SOCIAL WASPS 



The Social Wasps constitute the family Vespidse, of which 

 we have three genera, namely, Vcspa, Polistcs and Polybia, 

 the last genus being represented by a single Californian species. 



Vespa. Some species of Vespa, as V. macidata, make a 

 nest which consists of several tiers of cells protected by an 

 envelope (Fig. 281), attaching the nest frequently to a tree; 

 other species, as gennanica and vulgaris, make a nest under- 

 ground. The paper of which the nests are composed is manu- 

 factured from weather-worn shreds of wood, which are torn 

 off by the mandibles and then masticated with a secreted fluid 

 which cements the paper and makes it waterproof. 



A solitary queen founds the colony in spring ; she starts the 

 nest, lays eggs, feeds the young and brings forth the first 

 workers; these then relieve her continue the building opera- 

 tions, collect food, nurse the young, in short, assume the bur- 

 den of the labor. In the latter part of summer, fertile males 



