STATES OF INSECTS. (Jmago.) 339 
species, C. Campanularum, the segment in question has 
only a tubercle’. 
On the second segment of the abdomen of some spe- 
cimens, probably males, of the remarkable African ge- 
nus Pneumora before alluded to’, there are thirteen lit- 
tle elevated ridges, placed rather obliquely in an oblique 
series; and gradually, though slightly, diminishing in 
size towards the belly ; on their upper side they are flat, 
forming nearly a horizontal ledge, but on the lower they 
slope to the abdomen. ‘The posterior thigh in its natu- 
ral position covers the three first of them, and, if moved 
downwards, would strike them alle. I conjecture, there- 
fore, that these are the animal’s instruments of sound, 
imitating the harp or violin rather than the drum; and 
that the thigh acts the part of the hand or bow. The 
abdomen of these insects being blown out like a bladder, 
and almost empty‘, must emit a considerable sound when 
the thigh of the animal passes briskly over these ridges ; 
and their different length would produce a modulation 
in the sound. When struck with a pin, they emit a gra- 
ting noise. 
In Philonthus splendens, the penultimate ventral seg- 
ment is very deeply cleft, and the antepenultimate emar- 
ginate in one sex, and intire in the other. In Ph, lami- 
natus, an allied species, the penultimate segment is cleft, 
less deeply, however; but the antepenultimate is very 
short and intire; while the fourth is extremely long, and 
rounded at the margin, appearing as if it was only an 
elevated part of the last-mentioned segment ; for which 
* Mon. Ap. Angl. f. 13. a. > See above, Vot. II. 391. 
© Prare XXIX. Fic. 13. Stoll. Spectres, &c. t, xxv. f. 99. 
¢ Sparrman. Voyage, i. 312—. 
z2 
