I will go further: I ask myself in vain the reason of this or that trade in the case of a fixed species. The Osmiae make their partitions with mud or with a paste of chewed leaves; the Mason-bees build with cement; the Pelopaeus-wasps fashion clay pots; the Megachiles made disks cut from leaves into urns; the Anthidia felt cotton into purses; the Resin-bees cement together little bits of gravel with gum; the Carpenter-bees and the Lithurgi bore holes in timber; the Anthophorae tunnel the roadside slopes. Why all these different trades, to say nothing of the others? How are they prescribed for the insect, this one rather than that? I foresee the answer: they are prescribed by the organization. An insect excellently equipped for gathering and felting cotton is ill-equipped for cutting leaves, kneading mud or mixing resin. The tool in its possession decides its trade. This is a very simple explanation, I admit, and one within the scope of everybody: in itself a sufficient recommendation for any one who has neither the inclination nor the time to undertake a more thorough investigation. The popularity of certain speculative views is due entirely to the easy food which they provide for our curiosity. They save us much long and often irksome study; they impart a veneer of general knowledge. There is nothing that achieves such immediate success as an explanation of the riddle of the universe in a word or two. The thinker does not travel so fast: content to know little so that he may know something, he limits his field of search and is satisfied with a scanty harvest, provided that the grain be of good quality. Before agreeing that the tool determines the trade, he wants to see things with his own eyes; and what he observes is far from confirming the sweeping statement. Let us share his doubts for a moment and look into matters more closely. Franklin left us a maxim which is much to the point here. He said that a good workman should be able to plane with a saw and to saw with a plane. The insect is too good a workman not to follow the advice of the sage of Boston. Its industry abounds in instances where the plane takes the place of the saw, or the saw of the plane; its dexterity makes good the inadequacy of the implement. To go no further, have we not just seen different artisans collecting and using pitch, some with spoons, others with rakes, others again with pincers? Therefore, with such equipment as it possesses, the insect would be capable of abandoning cotton for leaves, leaves for resin, resin for mortar, if some predisposition of talent did not make it keep to its speciality.