_Rhombs, Pyramidal Bases, and Gross-sections of Cells illustrated._ _Honey-Comb._ _a_--Drone-cells, _b_--Deformed cells. _c_--Worker-cells. _d d_--Queen-cells. ] The structure of each cell is quite complex, yet full of interest. The base is a triangular pyramid (Fig. 28, _e_) whose three faces are rhombs, and whose apex forms the very centre of the floor of the cell. From the six free or non-adjacent edges of the three rhombs extend the lateral walls or faces of the cell. The apex of this basal pyramid is a point where the contiguous faces of three cells on the opposite side meet, and form the angles of the bases of three cells on the opposite side of the comb. Thus, the base of each cell forms one-third of the base of each of three opposite cells. One side thus braces the other, and adds much to the strength of the comb. Each cell, then, is in form of a hexagonal prism, terminating in a flattened triangular pyramid. The bees usually build several combs at once, and carry forward several cells on each side of each comb, constantly adding to the number, by additions to the edge. Huber first observed the process of comb-building, noticing the bees abstract the wax-scales, carry them to the mouth, add the frothy saliva, and then knead and draw out the yellow ribbons which were fastened to the top of the hive, or added to the comb already commenced. The diameter of the worker-cells (Fig. 28, _c_) averages little more than one-fifth of an inch--Réaumur says two and three-fifths lines or twelfths of an inch. While the drone-cells (Fig. 28, _a_) are a little more than one-fourth of an inch, or, according to Réaumur, three and one-third lines. But this distinguished author was quite wrong when he said: "These are the invariable dimensions of all cells that ever were or ever will be made." The depth of the worker-cells is a little less than half an inch; the drone-cells are slightly extended so as to be a little more than half an inch deep. These cells are often drawn out so as to be an inch long, when used solely as honey receptacles. The capping of the brood-cells is dark, porous, and convex, while that of the honey is white and concave. The character of the cells, as to size, that is whether they are drone or worker, seems to be determined by the relative abundance of bees and honey. If the bees are abundant and honey needed, or if there is no queen to lay eggs, drone-comb (Fig. 28, _a_) is invariably built, while if there are few bees, and of course little honey needed, then worker-comb (Fig. 28, _c_) is almost as invariably formed.