In the pharmacopœia of the ancients our wood-lice found a place. Reduced into powder, and mixed with various substances, they were prescribed as diuretic and aperient; but they were long ago abandoned in medicine. THE DRAGON-FLIES (_Libellulæ_). In walking along the banks of a river, you must frequently have seen hovering around you a cloud of insects, whom you would readily take to be butterflies, were not you arrested in your conjecture by the largeness of their head, the length of their body, the form of their vivid, diaphanous, gauze-like wings, and, generally,--which will most astonish you,--by their carnivorous instincts. You have about you and before, then, not butterflies, but Dragon-flies--the _Libellulæ_ of naturalists. They are the _demoiselles_, or "ladies," of the French; so called, perhaps, in allusion to their airy and graceful flight. Among these Libellulæ, one is called _Eleanora_. If she does not shine so brightly as the others--if her colours are less brilliant--she has, at least, the advantage of being so common that you can easily obtain a specimen. But, first, let us pause to think of the strange dissimilarity in the names bestowed on the _Libellulæ_ by the English and French respectively. They are the _Dragon-flies_ of the former,--fierce, rapacious, formidable; the _Ladies_ of the latter,--elegant, light, and radiant. Here we have a glimpse of national character. With the Frenchman, "appearance" counts for so much; with the Englishman, everything depends upon the "reality." Yet our English poets can appreciate their gay exterior. Moore speaks of them as-- "Those bright things which have their dwelling Where the little streams are welling!" Poor Clare, the Northamptonshire poet, correctly studied-- "The great dragon-fly with gauzy wings, In gilded coat of purple, green, and brown, That on broad leaves of hazel basking clings." And Mary Howitt has seen them-- "Here and there they dart, And flush like gleams of green and azure light." [Illustration: FIG. 37.--The Common Dragon-fly.]