The two wing-cases have exactly the same structure. To know one is to know the other. Let us describe the one on the right. It is almost flat on the back and slants suddenly at the side in a right-angled fold, encircling the abdomen with a pinion which has delicate, parallel veins running in an oblique direction. The dorsal surface has stronger and more prominent nervures, of a deep-black colour, which, taken together, form a strange, complicated design, bearing some resemblance to the hieroglyphics of an Arabic manuscript. By holding it up to the light, one can see that it is a very pale red, save for two large adjoining spaces, a larger, triangular one in front and a smaller, oval one at the back. Each is framed in a prominent nervure and scored with faint wrinkles. The first, moreover, is strengthened with four or five chevrons; the second with only one, which is bow-shaped. These two areas represent the Grasshoppers’ mirror; they constitute the sounding-areas. The skin is finer here than elsewhere and transparent, though of a somewhat smoky tint. The front part, which is smooth and slightly red in hue, is bounded at the back by two curved, parallel veins, having between them a cavity containing a row of five or six little black wrinkles that look like the rungs of a tiny ladder. The left wing-case presents an exact duplicate of the right. The wrinkles constitute the friction-nervures which intensify the vibration by increasing the number of the points that are touched by the bow. On the lower surface, one of the two veins that surround the cavity with the rungs becomes a rib cut into the shape of a hook. This is the bow. I count in it about a hundred and fifty triangular teeth or prisms of exquisite geometrical perfection. It is a fine instrument indeed, far superior to that of the Decticus. The hundred and fifty prisms of the bow, biting into the rungs of the opposite wing-case, set the four drums in motion at one and the same time, the lower pair by direct friction, the upper pair by the shaking of the friction-apparatus. What a rush of sound! The Decticus, endowed with a single paltry mirror, can be heard just a few steps away; the Cricket, possessing four vibratory areas, throws his ditty to a distance of some hundreds of yards. He vies with the Cicada in shrillness, without having the latter’s disagreeable harshness. Better still: this favoured one knows how to modulate his song. The wing-cases, as we said, extend over either side in a wide fold. These are the dampers which, lowered to a greater or lesser depth, alter the intensity of the sound and, according to the extent of their contact with the soft abdomen, allow the insect to sing mezza voce at one time and fortissimo at another.