The original circles of brood are gradually increased by the deposition of eggs in the cells next outside those already occupied, and circles are soon begun in the adjoining combs. In this way the space occupied by the developing bees is gradually increased, while preserving the general spherical shape of the brood nest thus formed, which, however, the shape of the hive often modifies somewhat. As already mentioned, each circle of brood has rows of pollen cells about it, chiefly above and at the sides, and the combs on either side contiguous to the brood are usually well packed with pollen. Outside of the pollen most of the honey on hand is stored. Thus (fig. 11) a cross section made in any direction through the middle of a hive in normal condition at the opening of the active season should show this relative arrangement of brood, pollen, and honey, which economizes most the heat of the hive and the labors of the nurse bees, favoring in this way the rapid increase of the population. [Illustration: Fig. 11.--Cross section of brood apartment: _s, s_, sides of hive; _t, t_, top-bars of frames; _h, p, l, sb_, combs containing (_h_) honey, (_p_) pollen, (_l_) larvæ and eggs, and (_sb_) sealed brood. (Original.)] THE WORKER. The worker larvæ are fed five days, and then the cell is given by the adult bees a covering which is quite porous by reason of numerous pollen grains incorporated into its mass, this openness of texture being necessary to give the developing bee air to breathe. The larva strength ens this capping by a loose webwork of silk within, extending down the side but slightly and attached at its edges to the last skin cast by the molting larva. This skin, extremely delicate and pressed closely against the inside of the cell, forms the lining of its sides and bottom. In about twelve days after sealing, that is, twenty-one days from the time the egg was deposited, the imago, or perfect bee, bites its way through the brown covering. In the course of a couple of days it takes up the work of a nurse, and in a week to ten days may appear at the entrance on pleasant days, taking, however, but short flights for exercise, as ordinary field work is not undertaken until it has passed about two weeks in the care of brood. The worker then takes up also wax secretion, if honey is to be capped over or combs built, although old bees can and do to a certain extent engage in wax production. THE DRONE. Eggs left unfertilized produce drones and require twenty-four days from the time they are deposited until the perfect insect appears. They are normally deposited in the larger-sized horizontal cells, and when the latter are sealed, the capping is more convex as well as lighter-colored than that of worker brood, which is brown and nearly flat.