BOM BUS. 317 



quired. A vaulted covering and sides is thus formed 

 or extended within the cavity by the plaiting or wreath- 

 ing together of these sprigs of moss, and the inside of 

 which is further strengthened by being plastered with a 

 coating of the pseudo-wax, which, however, srneljs much 

 like true wax, and with which the lower loose filaments 

 of the moss are intermingled, that one cannot be sepa- 

 rated from the other without tearing the whole to pieces. 

 Thus ingeniously do these insects enclose their home. 

 These nests are not always on the surface, but often 

 cavities of the necessary size are thus lined, and then 

 they are doubly secure. Within these nests, with the 

 increase of the population the number of the cocoons of 

 course increases, as they are never used twice over, ex- 

 cepting that when they are conveniently situated for the 

 purpose they are converted into honey pots. Thus 

 sometimes several layers are formed of these irregularly- 

 placed cocoons, of which the longest diameter is, how- 

 ever, always perpendicular to the horizon. In this way 

 B. muscorum } senilis, fragrans, and others build. Some 

 use a naked cavity, and merely secure it in its crevices 

 from the filtering intrusion of rain or other water, the 

 closing patches being formed of the usual waxy material. 

 This is the practice of B. terrestris, which associates the 

 largest communities of all; and B. lapidarius seeks 

 cavities among stones or in the earth, and forms a nest 

 of a regular oval, but merely clothes the sides, which is 

 done by bits of moss and grass carried carefully home. 

 The domestic arrangements within are much the same 

 in all, the prolific females and the neuters being the 

 labourers, which perform all the duties of building, the 

 collecting and caring for the young, the function of the 

 males being limited to the perpetuation of the species. 



