The tailor or leaf-cutting bees, of the genus Megachile, make wonderful cells from variously shaped pieces of leaves. These are always mathematical in form, usually circular and oblong, and are cut--by the insect's making scissors of its jaws--from various leaves, the rose being a favorite. I have found these cells made almost wholly of the petals or flower leaves of the rose. The cells are made by gluing these leaf-sections in concentric layers, letting them over-lap. The oblong sections form the walls of the cylinder, while the circular pieces are crowded as we press circular wads into our shot-guns, and are used at the ends or for partitions where several cells are placed together. When complete, the single cells are in form and size much like a revolver cartridge. When several are placed together, which is usually the case, they are arranged end to end, and in size and form are quite like a small stick of candy, though not more than one-third as long. These cells I have found in the grass, partially buried in the earth, in crevices, and in one case knew of their being built in the folds of a partially-knit sock, which a good house-wife had chanced to leave stationary for some days. These leaf-cutters have rows of hairs underneath, with which they carry pollen. I have noticed them each summer for some years swarming on the Virginia creeper, often called woodbine, while in blossom, in quest of pollen, though I never saw a single hive-bee on these vines. The tailor-bees often cut the foliage of the same vines quite badly. I have often reared beautiful bees of the genus Osmia, which are also called mason-bees. Their glistening colors of blue and green possess a luster and reflection unsurpassed even by the metals themselves. These rear their young in cells of mud, in mud-cells lining hollow weeds and shrubs, and in burrows which they dig in the hard earth. In early summer, during warm days, these glistening gems of life are frequently seen in walks and drives intent on gathering earth for mortar, or digging holes, and will hardly escape identification by the observing apiarist, as their form is so much like that of our honey-bees. They are smaller; yet their broad head, prominent eyes, and general form, are very like those of the equally quick and active, yet more soberly attired, workers of the apiary.