The _working bee-nymph_ spins its cocoon in thirty-six hours. After passing a certain period in this state of preparation for a new existence, it gradually undergoes so great a change, as not to wear a vestige of its previous form, but becomes armed with a firmer mail, and with scales of a dark brown hue, fringed with light hairs. On its belly six rings become distinguishable, which by slipping one over another, enable the bee to shorten its body whenever it has occasion to do so; its breast becomes entirely covered with gray feather-like hairs, which as the insect advances in age assume a reddish hue. When it has reached the twenty-first day of its existence, counting from the moment the egg is laid, it quits the exuviæ of the pupa state, comes forth a perfect winged insect, and is termed an _imago_. The cocoon or pellicle is left behind and forms a closely attached and exact lining to the cell in which it was spun: by this means the breeding-cells become smaller, and their partitions stronger, the oftener they change their tenants; and when they have become so much diminished in size, by this succession of pellicles or linings, as not to admit of the perfect development of full-sized bees, they are converted into receptacles for honey. Such are the respective stages of the working bee; those of the royal bee are as follow. She passes three days in the egg and is five a worm; the workers then close her cell[E], and she immediately begins spinning the cocoon, which occupies her twenty-four hours. On the tenth and eleventh days, as if exhausted by her labour, she remains in complete repose, and even sixteen hours of the twelfth. Then she passes four days and one-third as a nymph. It is on the sixteenth day therefore that the perfect state of queen is attained. [Footnote E: Instead of being nearly horizontal like the other brood-cells, those of the queens are perpendicular and considerably larger; in form they are oblong spheroids, tapering gradually downwards; their mouths being always at the bottom. _Vide_ Part II. "Architecture of Bees."]