142 
NATURE NOTES. 
and, considering the mode of capture, are in fairly good condi- 
tion. On examination they proved to belong to the same 
family as that most beautiful of British insects — the lace-wing 
fly, which, indeed, they closely resemble except as to size, 
their measurement across the expanded wings being a little 
over two inches ; they have since been identified by Mr. Kirby 
at the British Museum as Nothochrysa Gigantea. In 1870 it was 
observed that our lace-wing fly ( Chrysopa Perla) was possessed 
of a pygidium on each side of the terminal segment of the 
abdomen, similar in structure to that found on the flea, and 
regarded by many as an auditory organ. My first impulse 
therefore was to place this South African species under the 
microscope to see if it was similarly endowed, the search 
being speedily rewarded by the discovery of a pair of these 
remarkable organs, well developed, each containing about fifty- 
six distinct areolae, with long sensitive hairs rising from their 
centres. It may, therefore, fairly be inferred that whilst this 
complex structure is specially adapted to receive sounds made 
by its fellows, though entirely inaudible to us, the Nothochrysa 
is also able to appreciate others which we can hear so distinctly 
as the song of the Cicada. 
R. T. Lewis. 
[Mr. Lewis’s interesting and amusing description of a Cicada performing a solo 
before an appreciative audience of Lace-wings is, as he says in a private letter, so 
strange that it would sound like a “ traveller’s tale ” were it not for the entire trust- 
worthiness of the source from which it comes. From the same source Mr. Lewis 
has obtained several species of insects new to science, and some very curious infor- 
mation as to their habits, on which he has communicated memoirs to the Royal 
Microscopical Society and the Ealing Natural History Society, of both which he is an 
active member. For a full account of the vocal powers of the Cicada our readers 
are referred to the able Monograph of the British Cicada:, by Dr. G. B. Buckton, 
F.R.S., now in progress, the first volume of which is reviewed in another column. 
—Ed., N.N . ] 
THE UNFOLDING OF WOOD SORREL LEAVES. 
IR JOHN LUBBOCK has recently called attention to 
the way in which leaves are packed when in the bud, 
and the way in which they unfold themselves out of it. 
I do not know, however, whether he has ever mentioned 
the beautiful way in which the leaves of the common wood sorrel 
are developed, but it is so neat a contrivance, and may be so 
easily watched by any one who will go into a wood in early 
spring, that I should like to describe it here, for the benefit of 
those who have not noticed it before. 
Every one who knows anything about a wood in spring time, 
knows well the bright clusters of light green leaves which almost 
hide the delicate flower of the wood sorrel ; and everyone who 
has noticed them at all will remember their shape — a trefoil with 
little notches in the middle of each division. The mature leaf is 
