If it be urged that hard wood will not wear down the teeth like mining in the sandy soil, I can bring forward another member of this family (_Camponotus socius_, Roger), which lives in the ground, and whose mining and tunnelling are on a much more extensive scale than those of the harvesting-ant. The formicary of this _Camponotus_ often extends over several square rods, with large entrances at various points, all connected by underground galleries, requiring a great amount of labor to construct them; while each colony of the harvesting-ant has a close, compact nest or formicary, requiring much less work to construct it. The worker major of _Camponotus socius_ is very large--larger than the soldier of the harvesting-ant. The formicaries of the two species are often in close contact, so that the nature of the soil is precisely the same. I have examined thousands of _Camponotus socius_, and in no instance have I found the teeth worn down. There is still another difficulty in the way of Dr. Forel's theory. Careful observations have revealed the fact that all the harvesting-ants that engage in work of any kind are armed with teeth. I took thirty soldiers with smooth mandibles, put them in a glass jar with every facility for making a nest, but they refused to work, scorned all my offers of food, and remained huddled together for three days. I then introduced several workers minor, and they immediately commenced tunnelling the earth and making chambers, into which the lazy soldiers crawled, meeting with no opposition from these industrious little creatures. My experiments did not stop here. I now took about a hundred specimens--soldiers and a few workers major, the last with partially-developed teeth--and placed them in a jar. Some of these made feeble attempts to construct a nest, but they did not store away seeds, and larvæ which I put in the jar they carried about as if not knowing what to do with them. There is every appearance of an aristocracy among these humble creatures. The minors are the servants who do the work, while the queens and soldiers (especially the soldiers, which more nearly approach the queen in shape of head and mandibles) seem to live a life of comparative ease, and have their food brought to them by the minors. This may be the reason of the non-development of the teeth among the aristocracy. But how the same parent can produce such differing offspring--some born to a life of ease, with obsolete teeth, and others with well-developed teeth to do the work--is one of the mysteries in Nature. The only way to settle the point with regard to the mandibles beyond dispute is to find the pupæ of very young queens and soldiers, which I was unable to do during my stay in Florida. All the young were in the larval state. MARY TREAT. DOCTEUR ALPHÈGE. "Marcelline! Marcelline! viens m'aider: je souffre!"