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Notes on the stridulating organ and stink-glands of Tessa- 
ratoma papillosa, Zrunb. By FREDERICK Muir, F.ES. 
The sound-producing organs of this insect are situated 
on the anterior dorsal part of the abdomen and upon the 
under-side of the wings, and consist of a movable striated 
surface, the file, which passes across strong chitinous teeth, 
the comb. A sclerite, spatulate at each end, runs across 
the abdomen between the metathorax and the first abdo- 
minal segment. Situated at each end of this sclerite, 
upon the spatulate part, is a round, convex and highly- 
chitinous spot finely striated transversely, the file. A 
strong muscular system is attached to the edge of this 
sclerite by means of which it is enabled to move backward 
and forward over an arc of about 35 degrees, having an 
imaginary axis passing from side to side of the abdomen ; 
the whole sclerite moves at once, so that the files act in 
unison and cannot move independently. This rotatory 
movement of the files makes it necessary that they should 
have a convex surface to keep them in contact with the 
comb situated upon the wing. The folding under of the 
wing along the claval suture brings the membrane between 
the file and the comb, and this membrane is often abraded 
at that spot, especially in old specimens. This membrane 
does not affect the sound at all, for it is of equal volume 
whether the membrane be cut off or not. If the wings be 
cut off and the insect irritated the files move rapidly, but 
of course no sound is produced ; the same thing happens 
if a female be placed near a male and watched for a little 
time. Figs. 1 and 2 show the position of these organs. 
In the later nymphal stages of this bug there are four 
stink-glands opening at the posterior margin of the second, 
third, fourth and fifth segments; the first and fourth of 
these glands are functionless, I cannot state if all four 
glands exist in the earliest stages as I have not been able 
to procure specimens, but it is interesting to note that, 
they are not able to secrete obnoxious fluid during these 
stages. This is not what I should have expected, as the 
presumably protective value of this fluid would be most 
valuable to the young. 
