Now why do the Labiatæ, the Personatæ and other vegetable orders present these anomalies which completely disarrange the regular structure of the flower? Let us in this connection venture upon an architectural comparison. The first men who ventured to balance heavy hewn stones over empty space, thereby deserving the proud title of pontifex, or bridge-builder, took as the pattern of their fabric the semicircular arch, which rests the thrust of the load on uniform voussoirs. The result is strong and majestic, but also monotonous and lacking in elegance. Next came the pointed arch, which opposes two arcs described from different centres. With the new type, soaring curves, slender ribs and magnificent superstructures are possible. Variety, inexhaustible in its graceful combinations, replaces monotony. Well, the regular corolla is, so to speak, the semicircular arch of the flower. Whether campanulate, rotate, urceolate, stellate, or of any other shape, it is always a grouping of similar parts around a circumference. The irregular corolla is the ogive, with its wonderful audacities; it lends to the poetry of the flower the admired disorder of all true poetry. The thick-lipped mask of the snapdragon, the gaping jaws of the sage are every whit as effective as the rosette of the hawthorn or the sloe. They are so many chromatic notes added to the gamut, so many charming variations upon one glorious theme, so many discords that enhance the value of the harmonies. The floral symphony gains if interrupted by occasional solos. The Pedestrian Locust, hopping among the saxifrage amid the lofty summits of the hills, explains his incapacity to fly by reasons of a like order; so does the Staphylinus his skimpy jacket, the Necydalis his short coat, the Myodites her Fly-like aspect. Each after his fashion varies the monotony of the general theme; each strikes a special note in the universal concert. It is not so easy to see why the Scarab abandons his fore-tarsi, why the Iris-beetle has only one claw to her fingers, why the Geotrupes-grub is born mutilated. To what are these minute aberrations due? Before answering, let us once again take counsel with the plant. One of the inmates of our hothouses is the Alstrœmeria pelegrina, or Inca lily, a native of Peru. This curious plant sets us a puzzling problem. At the first glance, its leaves, shaped more or less like those of the willow, offer nothing that deserves attentive examination; but look at them more closely. The leaf-stalk, flattened into a ribbon of some length, is tightly twisted upon itself; and the twist is repeated on every one of the leaves. From one end of the plant to the other we find this clearly-marked torsion.