caresses with his antennæ the mate he has won.”[455] Dr. Scudder was able to excite one of these insects to answer him, by rubbing on a file with a quill.[456] In both sexes a remarkable auditory apparatus has been discovered by Von Siebold, situated in the front legs.[457] [Illustration: Fig. 10. Gryllus campestris (from Landois). Right-hand figure, under side of part of the wing-nervure, much magnified, showing the teeth, _st_. Left-hand figure, upper surface of wing-cover, with the projecting, smooth nervure, _r._, across which the teeth (_st_) are scraped.] In the three Families the sounds are differently produced. In the males Of the Achetidæ both wing-covers have the same structure; and this in the field-cricket (_Gryllus campestris_, fig. 10) consists, as described by Landois,[458] of from 131 to 138 sharp, transverse ridges or teeth (_st_) on the under side of one of the nervures of the wing-cover. This toothed nervure is rapidly scraped across a projecting, smooth, hard nervure (_r_) on the upper surface of the opposite wing. First one wing is rubbed over the other, and then the movement is reversed. Both wings are raised a little at the same time, so as to increase the resonance. In some species the wing-covers of the males are furnished at the base with a talc-like plate.[459] I have here given a drawing (fig. 11) of the teeth on the under side of the nervure of another species of Gryllus, viz. _G. domesticus_. [Illustration: Fig. 11. Teeth of Nervure of Gryllus domesticus (from Landois).] In the Locustidæ the opposite wing-covers differ in structure (fig. 12), and cannot, as in the last family, be indifferently used in a reversed manner. The left wing, which acts as the bow of the fiddle, lies over the right wing which serves as the fiddle itself. One of the nervures (_a_) on the under surface of the former is finely serrated, and is scraped across the prominent nervures on the upper surface of the opposite or right wing. In our British _Phasgonura viridissima_ it appeared to me that the serrated nervure is rubbed against the rounded hind corner of the opposite wing, the edge of which is thickened, coloured brown, and very sharp. In the right wing, but not in the left, there is a little plate, as transparent as talc, surrounded by nervures, and called the speculum. In _Ephippiger vitium_, a member of this same family, we have a curious subordinate modification; for the wing-covers are greatly reduced in size, but “the posterior part of the pro-thorax is elevated into a kind of dome over the wing-covers, and which has probably the effect of increasing the sound.”[460] [Illustration: Fig. 12. Chlorocœlus Tanana (from Bates). _a_, _b_. Lobes of opposite wing-covers.]