LEAF-CUTTING BEES
These are amongst the specially interesting of the bees in their habits. They are dull-brown coloured creatures rather like a stout hive bee in form ([pl. C], 20). They all collect pollen on the underside of their body. They burrow either in decayed wood or in the ground, but they make their cells of pieces of leaves which they cut off from rose bushes or other plants; these cells when completed are wonderful works of art. Probably some of my readers may have noticed rose leaves with semicircular pieces cut out of them, and often with almost circular ones; this is the work of the leaf cutter (fig. 7).
20. Megachile maritima, female. 21. Cœlioxys conoidea, male. 22. Cœlioxys conoidea, female. 23. Nest of Megachile willughbiella.
[face p. 52.
She alights on a leaf, holds on to the edge of the piece she wants to cut off with her legs, and then cuts it out by means of her jaws, or mandibles; as soon as it is cut free she uses her wings and so prevents herself from falling, and goes off with the cut off piece safely held under her body by her legs. I have frequently seen bees flying home with their leafy burden, and once or twice I have seen them cutting the pieces out. They cut round the piece they select with great rapidity—the marvel is that they can arrange so exactly as not to fall when the last attachment is removed. The pieces they cut have to be of several shapes in order to build up the cell they require; some are more or less lozenge shaped, some almost circular; the cells they make are somewhat thimble-shaped. The lozenge-shaped pieces are used to build up the sides and lower end of the cell, and the circular pieces to close it in with at the top; it is all cemented together with a gluey substance excreted by the bee. The burrows of the leaf-cutters are made, as stated above, either in the ground or in rotten wood. I have never had a subterranean nest to examine, but have had several nests in rotten wood under my notice, one of which is now before me ([pl. C], 23). It is in a piece of very
soft willow, almost in a touchwood condition. So that by carefully cutting away the wood I have been able to expose the whole series of cells. Two distinct burrows run almost parallel to each other; both of them are slightly curved and each has contained six cells; these are about half an inch long, and they fit one over another in the tube as closely as possible so as to look like two long thick green worms. Each cell is composed of many pieces of leaf, and the final plug which closes the cell is often made of several rounds of leaf one over the other. The amount of labour taken by the mother bee to make these cells must be enormous. The cells are provisioned like those of any other solitary bee with pollen, etc., and the egg is laid upon it. Most of the leaf-cutters have their attendant cuckoos, which are rather smaller than themselves, of a deep black with white bands on the sides of the body. The female has a very pointed tail, and the male's body ends in a series of spine-like projections ([pl. C], 21, 22).