354 
SEXUAL SELECTION. 
Part H* 
Fig. 11. Teeth of Nervure 
of Gryllus domesticus 
(from Lundois). 
scribed by Landois, 32 of from 131 to 138 sharp, trans- 
verse ridges or teeth (si) 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 re- 
sonance. In some species the wing' 
covers of the males are furnished 
the base with a talc-like plate.® I 
have here given a drawing (fig. U) 
of the teeth on the under side of the 
nervure of another species of Gryllus, 
viz. G. domesticus. 
In the Locustidie the opposite wing-covers differ h 1 
structure (fig. 12), and cannot, as in the last family 
be indifferently used in a reversed manner. The led 1 
wing, which acts as the bow of the fiddle, lies over the 
right wing which serves as the fiddle itself. One o*' 
the nervures (a) on the under surface of the former k 
finely serrated, and is scraped across the prominent 
nervures on the upper surface of the opposite or rigid 
wing. In our British Fhasgonura viridissima it a P' 
peared to me that the serrated nervure is rubbo 
against the rounded hind corner of the opposite win-' 
the edge of which is thickened, coloured brown, 
very sharp. In the right wing, but not in the 1°^’ 
there is a little plate, as transparent as talc, surround® 
by nervures, and called the speculum. In Ephippi'J 11 ' 
vitium, a member of this same family, we have a curio 11- 
32 1 Zeitschrift fur wissenschaft. Zoolog.’ B. xvii. 1867, s. 117. 
33 AVeatwood, ‘ Modern Class, of Insects,’ vol. i. p. 440. 
