The solitary and digger wasps do not live in communities as the hornets do, but each female makes a nest or several nests of her own, lays eggs and provides for her own young. The nest is usually a short vertical or inclined burrow in the ground, with the bottom enlarged to form a cell or chamber. In this chamber a single egg is laid, and some insects or spiders, captured and so stung by the wasps as to be paralyzed but not killed, are put in for food. The nest is then closed up by the female, and the larva hatching from the egg feeds on the enclosed helpless insects until full grown, when it pupates in the cell and the issuing adult gnaws and pushes its way out of the ground. Each species of wasp has habits peculiar to itself, making always the same kind of nest, and providing always the same kind of food. Some of these wasps make their nests in twigs of various plants, especially those with pithy centres in the stems. For interesting accounts of the habits of several digger wasps see Peckham's "The Solitary Wasps." The solitary bees, of which there are similarly many kinds, are like the solitary wasps in general habit, only they provision the nest with a mixture of pollen and nectar got from flowers instead of with stung insects. Sometimes many individuals of a single species of solitary bee will make their nests near together and thus form a sort of community in which, however, each member has its own nest and rears its own young. In the case of certain small mining bees of the genus _Halictus_, a step farther toward true communal life is taken by the common building and use by several females of a single vertical tunnel or burrow from which each female makes an individual lateral tunnel, at the end of which is a brood-chamber. Perhaps half a dozen females will thus live together, each independent except for the common use of the vertical tunnel and exit. The bumblebees (_Bombus_ sp.) are truly communal in habit. All the eggs are laid by a queen or fertile female, which is the only member of the colony to live through 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 larvæ, 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 produced. 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 communities in the spring.