When a hive has been in use many years the combs become very black, and every bee that is bred in a cell leaves a film behind. It may be understood how in this way the cells become contracted, and the bees that are bred in them correspondingly reduced in size. After the lapse of, say, five years it may be necessary to begin removing the old combs. This may be done by cutting away the combs, or by substituting an empty frame for one with old black comb, gradually moving the frames towards each other. By taking two away in this manner in the spring or summer of every season, the combs in course of five years may all be reconstructed, and fresh clean ones be secured for breeding in, instead of the old black ones that otherwise would remain as long as the stock could live in the hive. Guide-combs can also be used with glasses. These may be filled, with great regularity, by adopting the following directions, which, we believe, have never before appeared in print:-- Procure a piece of clean, new, empty, worker honeycomb, which has not had honey in it (because honey will prevent adhesion to the glass); cut it into pieces of about three-quarters of an inch square. Gently warm the exterior of the glass (this we find is best done by holding the glass horizontally for a short time over the flame of a candle); then apply one of the pieces of empty comb inside at the part warmed, taking care, in fixing it, that the pitch or inclination of the cells is upwards--in fact, place the guide-comb in the same relative position that it occupied in the hive or glass from which it was taken. There is some danger of making the glass too warm, which will cause the wax to melt and run down the side, leaving an unsightly appearance on the glass; but a little experience will enable the operator to determine the degree of warmth sufficient to make the comb adhere without any of it being melted. It is hardly necessary to state that only the very whitest combs ought to be used. A short time should be allowed before changing the position of the glass, so that it may cool sufficiently to hold the comb in its place. Six or eight pieces may thus be fixed, so that, when the glass is filled, it will present a star shape, all the combs radiating from the centre. The annexed illustration shows the appearance of a glass as worked by the bees, in which guide-combs were fixed in the manner described above. The drawing was taken from a glass of our own, filled after being thus furnished. In the Old Museum at the Royal Gardens, Kew, may be seen a Taylor's glass, presented by us, some of the combs in which are elongated on the outside to the breadth of six inches. [Illustration]