Minutes of Proceedings. xxi 
“Ordinary Members of the Society. Mr. J. HH. Brady,, M.A., Dr. 
CG. T. Wood, M.Inst.C.E., Mr. R. H. Hammersley-Heenan, M.Inst.C.E. 
Mr. R. Trimen exhibited some living specimens of both sexes of the 
remarkable South African orthopterous insect, Cystocelia sex-guttuta 
(Thumberg), received at the Museum from Dr. Schonland, Curator of 
the Albany Museum at Grabam’s Town. 
He called attention to the well-known extreme disparity in form 
between the sexes exhibited by the insects of this genus and of the 
closely-allied genus Pneumora, the male having an inflated, semi- 
transparent, bladder-like abdomen, while that part of the body in the 
female is of the ordinary compact, laterally-compressed, elongate, but 
massive form general in the larger kinds of locusts of the family 
Acridide. The males of those two genera have, as Darwin remarks 
(“ Descent of Man,” 1, p. 357), been more profoundly modified for the 
sake of stridulation than any other orthopterous insect ; for the whole 
body has been converted into a musical instrument, being distended 
with air, like a great pellucid bladder, so as to increase the resonance. 
In most of the musical males of crickets, locusts, and grasshoppers, 
stridulation is produced by friction together of the prominent ribbed or 
toothed veins of the wing-covers, or by tae rubbing of the toothed 
inner surface of the femur of the hind-leg against those veins, but in 
Cystocelia and Pneumora the sound is caused by the friction of the 
same surface of the much reduced hind-leg along a sharply-ribbed or 
tuberculated curved ridge prominent on each side of the inflated 
abdomen, on the second segment. Species of this curious group are 
met with throughout Sonth Africa,—three or four being found in the 
neighbourhood of Cape Town,-—but the insect exhibited, C. sex- 
_ guttata, is by far the largest known species. Apart from the extra- 
ordinary disparity in the abdominal region, very wide differences are 
conspicuous in the size and shape of the dorsal shield of the prothorax 
_ and of the wings and tegmina,—the latter being voluminous in the 
male, but small and useless for flight in the female. Although 
belonging to an eminently saltatorial family, the hind-legs in both 
sexes of these insects are so reduced that leaping is impossible. 
_ The point which Mr. Trimen wished particularly to bring to notice 
in the case of C. sex-guttata is that the species offers a very striking 
instance of reversal of the usual comparative brightness of colouring 
in the sexes, the female (described by Latreille as Pneumora 
sceutellaris) being far more beautiful than the male both in tints and 
-markings. She is of a bright yellow-green, with very numerous and 
