NOISES OF INSECTS. 495 
of other insects, my further observations will be confined to the tribes 
lately mentioned, the Gryllina, &c., and the Cicade, 
No sound is to me more agreeable than the chirping of most of the 
Gryllina, Locustina, &c. ; it gives life to solitude, and always conveys tomy 
mind the idea of a perfectly happy being. As these creatures are now very 
properly divided into several genera, I shall say a few words upon the song 
of such as are known to be vocal, separately. 
The remarkable genus Preumora—whose pellucid abdomen is blown up 
like a bladder, on which account they are called Blaazops by the Dutch 
colonists at the Cape—in the evening, for they are silent in the day, — 
make a tremulous and tolerably loud noise, which is sometimes heard on 
every side. The species of this genus have a claim to the name of Fid- 
dlers, since their sound is produced by passing the hind-legs, which are 
furnished with a series of smooth elevated ridges, and may be called the 
fiddle-sticks, over a number of short transverse elevated ridges, of a similar 
though slightly different structure, on the abdomen, which may be called 
the strings.? 
The cricket tribe are a very noisy race, and their chirping is caused by 
the friction of the cases of their elytra against each other. For this pur- 
pose there is something peculiar in their structure, which I shall describe 
to you. The elytra of both sexes are divided longitudinally into two 
portions; a vertical or lateral one, which covers the sides; and a horizon- 
tal or dorsal one, which covers the back. In the female both these por- 
tions resemble each other in their nervures ; which running obliquely in two 
directions, by their intersection, form numerous small lozenge-shaped or 
thomboidal meshes or areolets. The elytra also of these have no elevation 
at their base. In the males the vertical portion does not materially differ 
from that of the females; but in the horizontal the base of each elytrum 
is elevated so as to form a cavity underneath. The nervures also, which 
are stronger and more prominent, run here and there very irregularly with 
various inflexions, describing curves, spirals, and other figures difficult and 
tedious to describe, and producing a variety of areolets of different size 
and shape, but generally larger than those of the female ; particularly to- 
wards the extremity of the elytrum you may observe a space nearly cir- 
cular, surrounded by one neryure, and divided into two areolets by 
anothers The friction of the nervures of the upper or convex surface of 
the base of the left-hand elytrum — which is the undermost — against those 
of the lower or concave surface of the base of the right-hand—which is 
the uppermost one, will communicate vibrations to the areas of membrane, 
more or less intense in proportion to the rapidity of the friction, and 
thus produce the sound for which these creatures are noted ; which, how- 
ever, according to M. Goureau, in his elaborate essay on the stridulation 
of insects, is chiefly owing to the circumstance of one of the strong ner- 
vures called by hita the dow (Varchet) being striated or cut transversely 
like a file, whence it has a much more powerful action on another 
collection of neryures which he calls the éreble-string (la chanterelle).* 
The merry inhabitant of our dwellings, the house-cricket (Gryllus do- 
mesticus), though it is often heard by day, is most noisy in the night. As 
1 Sparrman, Voy. i. 312. .. 
2 Charpentier in Silbermann’s Revue Entom. iii, 314. 
5 Compare De Geer, iii. 512. 
4 Ann, Soc. Ent. de France, and Entom. Mag. v. 94. 
