The eggs (Plate II., fig. 7) of all the three kinds of bees, when first deposited, are of an oval shape, and of a pearly-white colour. In four or five days the egg changes to a worm, and in this stage is known by the names of larva or grub (Plate II., fig. 8), in which state it remains four to six days more. During this period it is fed by the nurse-bees with a mixture of farina and honey, a constant supply of which is given to it. The next transformation is to the nymph or pupa form. The nurse-bees now seal up the cells with a preparation similar to wax, and then the pupa spins round itself a film or cocoon, just as a silkworm does in its chrysalis state. The microscope shows that this cradle-curtain is perforated with very minute holes, through which the baby-bee is duly supplied with air. No further attention on the part of the bees is now requisite, except a proper degree of heat, which they take care to keep up--a position for the breeding cells being selected in the centre of the hive, where the temperature is likely to be most congenial. Twenty-one days after the egg is first laid (unless cold weather should have retarded it) the bee quits the pupa state, and, nibbling its way through the waxen covering that has enclosed it, comes forth a winged insect. The eggs of drones require twenty-four days, and those of queens sixteen days, to arrive at maturity, and are hatched in warm summer weather, a higher temperature being necessary. In the Unicomb Observatory Hives, the young bees may distinctly be seen as they literally fight their way into the world, for the other bees do not take the slightest notice, nor afford them any assistance. We have frequently been amused in watching the eager little new-comer, now obtruding its head, and anon compelled to withdraw into the cell to escape being trampled on by the apparently unfeeling throng, until at last it has succeeded in making its exit. The little grey creature, after brushing and shaking itself, enters upon its duties in the hive, such as the nursing before alluded to, or secreting wax, and in (say) a week issues forth to the more laborious occupation of gathering honey in the fields--thus early illustrating that character for industry which has been proverbial at least since the days of Aristotle, and which has in our day been rendered familiar even to infant minds through the nursery rhymes of Dr. Watts. INCREASE OF BEES.