Saved by the Snail from the hard task of excavation, she specializes in mosaic and produces a work of art which is superior in elegance to the miner’s temporary guilloche. Her materials are, on the one hand, resin; on the other, little bits of gravel. Her method is very unlike that of the two resin-workers who find a lodging in the shell of the Edible Snail. These two swamp with gum, on the outer surface of the lid, their coarse, angular bricks, which are unequal in size, variable in nature and often of a half-earthy character, so that the unevenness of the work, in which the pieces are laid side by side at random, is hidden under a coat of resin. On the inner surface the gum does not fill the gaps and the cemented fragments appear with all their irregular projections and their clumsy arrangement. Remember also that the bits of gravel are kept exclusively for the operculum, or lid, the final covering; the partitions which mark off the cells are made entirely of resin, without any mineral particles. The Alpine Odynerus works on a different plan: she saves pitch by making better use of stone. A number of round, flinty atoms are set in a bed of still sticky cement, on the outer surface. They fit one against the other, are almost all of the same size, that of a pin’s head, and are selected singly by the artist amid the miscellaneous rubbish that litters the ground. When it is well-executed, as is frequently the case, the result suggests a piece of embroidery worked with roughly-fashioned beads of quartz. The Anthidia of the Snail-shell, rude labourers that they are, accept all that falls to their mandibles: angular splinters of limestone, morsels of flint, bits of shell, hard particles of earth; the daintier Odynerus as a rule inlays with beads of flint only. Can this taste for gems be due to the brilliancy, the translucency, the polish of the grain? Can it be that the insect takes pleasure in its casket of precious stones? The answer will be the same as in the case of the ornamental rose-window, the tiny shell sometimes inserted in the centre of the lid by the two resin-gatherers who inhabit the shell of the Edible Snail: why not? Be this as it may, the gem-collector is so pleased with her pretty pebbles that she puts them everywhere. The partitions that subdivide the shell into chambers are reproductions of the lid: each has a carefully-finished mosaic of translucent flints on the front surface. In this manner three or four cells are contrived in the shell of the Edible Snail; in that of the Bulimulus, two at most. The cells are small but correctly shaped and strongly protected.