200 Dr. David Sharp on 
though these surfaces are not stridulating organs, I 
think it quite possible they may be used by friction for 
producing rustling sounds of considerable variety, though 
at present there is no evidence to that effect. The figure 
given by Swinton is altogether erroneous; he in part 
indicates the spot where the stridulating organ in 
Myrmica is really situated, but, instead of figuring the 
sculpture that is actually there, he has delineated a 
striation that does not exist; he has, in fact, trans- 
ferred the general sculpture to the spot from which it is 
in reality absent, being replaced by the stridulating 
surface. Swinton’s figure was reproduced by MacCook, 
and thus obtained a curreney which is to be regretted, 
as if may probably have misled observers. He was no 
doubt in part deceived by insufficient glasses, for the 
stridulating surface in Myrmica is so beautifully formed 
and so delicate that it appears smooth and_ polished 
until a high power and a proper light are applied so as 
to resolve the lines. 
Kntomologists who have discussed this subject have 
mostly stated that no purposeful sounds audible to 
human ears are produced by ants, though some cases 
have been recorded in which sound was produced by the 
ants striking their heads in concert on a foreign sub- 
stance, such as a dry leaf. It is no doubt true that the 
stridulation of most of the species of ants that occur in 
Kurope cannot be directly detected by the human ear, 
but this is not by any means true for all ants. Mr. R. 
C. Wroughton, who has within the last few weeks pub- 
lished an excellent paper on the ants of India, discusses 
Lubbock’s statement that ants produce no sounds that 
are audible to us; saying, ‘‘l am almost certain, how- 
ever, that I have heard such sounds. When one of the 
large brown paper nests of Cremastogaster rogenhofert is 
violently and suddenly disturbed, the ants swarm out in 
thousands, wagging their abdomens in the manner so 
characteristic of Cremastogaster when excited; at such 
times a distinct hissing sound is audible, as if a red-hot 
cinder had been plunged into water. I had always 
accounted for this by supposing it was caused by the 
material of the nest under the feet of the ants, and a 
similar though fainter sound, which may be heard when 
a large nest of Camponotus or Polyrhacis spinigera is 
disturbed, by the rubbing together of the bodies of the 
