NATURAL HISTORY NOTES 
155 
If we sum up the whole of the evidence which has been put forward upon 
the subject of hearing in insects (it is far too bulky to quote in so small a space), it 
will be found to amount to practically nothing. Graber, one of the most volu- 
minous and frequently quoted writers in this branch of investigation, contradicts 
himself more than once. He first stated that the organ of hearing in insects 
existed in the head, then in the antenna;, then that the sense is disseminated 
throughout the body. 
In conclusion, what may be considered as proof of hearing appears to Duges 
and Forel (and from my own small observations, I can only agree with them) to 
rest, with few exceptions, almost certainly on mechanical vibrations of the air or 
ground. These are simply perceived as such by the tactile organs of insects, as 
Duges says : “ A pseudo-audition, consisting in the perception of mechanical 
vibrations by the whole body.” This almost corresponds to the opinion last 
expressed by Graber as to the “ hearing ” of Periplaneta, and it is probably the 
explanation of the behaviour of Mr. Avery’s caterpillars. 
Macleod Yearsley. 
388. “ Honeydew. ” ■ — Enclosed are some leaves of common lime 
(Tilia vulgaris ) coated as you may see with “ Honey-dew.” 
It is several years now since such a flow of this secretion took place as 
we see this year— due more especially to hot and dry summer weather. The 
leaves, which are entirely glazed over with the sticky liquid, I have gathered from 
a tree without flowers, neither is there any other tree of its kind, or others with 
flowers, within a considerable distance to attract insects. For a week I have 
made daily and nightly observations, with the result that I have found very little 
signs of Aphides or other insect life to cause so great a flow of nectar. The 
few I have found appear lifeless, having become transfixed, like flies settling on 
plants of the sundew, to the sticky fluid. So that I think it impossible for such 
a few, just here and there, to cause so great an exudation. The tree from which 
I have made my observations stands in the open, where the direct rays of the 
hot sun are upon it throughout the day. Last evening, Friday, July 13, I noticed 
moisture dropping from the tree at 9 o’clock ; at 10.30 it was dropping much 
faster, as though rain was falling from the tree. The leaves I examined were 
then saturated with “ Honey-dew,” but with no more consistency than water, 
but, as soon as touched with the warm hand, it became sticky, like gum. Even 
the warm room into which I took them caused the thin moisture to harden 
in a few minutes’ time. The amount of moisture which falls from this tree every 
evening is about a pint and a half to a quart. 
I cannot think it possible for insect life to be responsible for such a large 
exudation. I may say that the leaves I gathered last evening when the nectar 
was falling contained no insect life of any kind whatever. 
P.S. — The couple of sycamore leaves are from a tree growing near. 
41, Heath Street, Hampstead. N. IV. James E. Whiting. 
[In inserting a note on this subject we would remind our readers that it was 
copiously discussed last year, so that only new observations or deductions are 
desirable. We have ourselves noticed this summer (i.) that the drip takes place 
from poplar ( Popultis inonilifera ), though less copiously than from linden ; (ii.) 
that it is more copious from lindens having a southerly or sunny aspect than 
from others; (iii.) that it occurs equally from flowering specimens, and from 
young trees or pollards which do not flower ; (iv.) that the glaze occurs on the 
upper surface of the uppermost leaves of trees not overhung by others, and on 
the upper surface of leaves on long sprays projecting beyond the rest of the 
tree. — Ed. N.N.] 
389. Plants on the Chalk. — I came upon a remarkable sight yesterday 
on the marly slopes of the chalk hills above Buckland village — to wit, a colony of 
Viper’s Bugloss, the plants of which varied from two to three feet in height. 
The prevailing colour was the usual intense blue, but some of the plants were 
pure white, and others of a paler blue. I should think that a quarter of an acre 
of ground must have been covered by these giants, and the effect was very fine. 
I noticed in the same field, Ophrys apifera , Ajuga Chamcepitys, Carduus nutans 
(a very handsome thistle), Polygonum Fagopyrum (abundant, thanks no doubt to 
the pheasant breeder), and Malva moschata. The last named was not frequent, 
