1824.) 
vices of the bark for the purpose of deposit- 
ing its eggs ; and on stripping off a piece of 
the loose bark, we may, at any season, un- 
derstand how the barking of trees is effect- 
ed by these minute animals, for the surface 
of the wood thus exposed presents innu- 
merable impressions of worms, which may 
be compared to casts of broad scolopendriz. 
The middle of these impressions marks the 
path of the perfect female insect while em- 
ployed in laying her eggs, which operation, 
as in most other insects, is the immediate 
precursor of death. The larve, or worms, 
remain throughout the winter feeding on 
the tree between the bark and wood. 
During the early part of the spring they 
acquire the pupa state, when the bark of a 
diseased tree has the interstices filled with 
a sort of fine saw-dust. After which, the 
animal attains its winged state, and pierces 
the holes before-mentioned, in order to ob- 
tain its liberation, and to escape and mi- 
grate to other trees for the purpose of pro- 
pagating its species. In the first instance, 
the yoracity of the larve, and next the per- 
fect insect endeavouring to liberate itself 
from the wood, when these animals exist 
in immense numbers, soon occasions the 
bark to fall inpieces. The consequence is, 
that new leaves only make their appear- 
ance, they wither in a short period, and the 
tree perishes.”’ 
Mr. M. advises those persons who 
have any elm-trees in the state before- 
mentioned, to have them inspected every 
half year—in the summer, when the 
perfect insect is formed; and in the 
winter, when those trees are most in- 
fected ought to be cut down. And it is 
not sufficient that the trees be cut, for 
if they are allowed to remain in the 
ground till the spring, the formation of 
these insects will still go on and infect 
other trees in its vicinity. If the timber 
cannot be removed, the surface ought 
to be scorched, or at least fumigated, so 
as to destroy the nidus of these animals. 
This kind of beetle is peculiar to the 
elm, for the other species of trees in the 
parks are free from their depredations. 
And Mr. M. very justly remarks, that 
In planting, especially in ornamental 
plantations, it should be borne in mind, 
that indigenous trees are much more sub- 
ject to the attacks of our indigenous in- 
sects, than those which are not natives of 
this country. 
With regard to the remedy to be ap- 
plied in these cases, it must obviously 
depend on the extent of the disease. 
If the branches of a tree are.only affect- 
ed, they should be lopped off without 
delay and burnt. But if the trunk be 
attacked, Mr. M. recommends a mix- 
ture of tar and train oil to be applied 
over the bark to a certain extent from 
the ground, for the purpose of arresting 
On Aérostation. 
295 
the further progress of these destructive 
animalcule.* The subject appears to 
me to demand serious attention, and 1 
could have wished Mr. Macleay, or 
some other able naturalist, would give 
a brief description of all the parasitical 
insects and plants which commit such 
havoc in our orchards, gardens, and 
shrubberies. A work of that kind would 
be infinitely valuable, not only to indi- 
viduals, but in a national point of view. 
Many of the diseases of plants, espe- 
cially of the more delicate species, must 
be considered as local, and arising from 
the great vicissitudes of our climate. 
But-an essay or popular treatise on the 
production of the various kinds of fungi, 
and the connection that appears . to 
exist between the formation of this 
parasitical class of vegetation, and the 
peculiar soil on which it is more or less 
prevalent, could not fail to prove highly 
valuable to all who have the smallest 
taste for the beautiful pursuits of hor- 
ticulture. 
——a——— 
For the Monthly Magazine. 
ON AiROSTATION. 
HEN we consider the extreme 
liability to accident which at- 
tends the ascent and descent of a bal- 
loon, even under the most skilful 
management, it seems truly astonishing 
that any individual should undertake so 
perilous an excursion for the mere gra- 
tification of a gaping multitude ; for it 
is extremely doubtful whether, as a pe- 
cuniary speculation, it has answered the 
expectations of the aéronauts in one 
case out of ten. The present summer 
having produced two instances of fatal 
results, Mr. Harris and Mr, Sadler ; 
and several failures having occurred to 
other aéronauts, it is presumed we shall 
hear no more of these worse than use- 
less excursions. If any objects con- 
nected 
* The writer of this article, from his own 
experience, begs to recommend the addi- 
tion of caustic, or recent lime, to the tar or 
oil, as it kills the insects, while it fills up 
the cayities of a diseased tree. The coal- 
tar and ammoniacal liquor of the gas-works 
would be far the cheapest commodity for 
this purpose, and probably be more effec- 
tive than vegetable tar. Its disagreeable 
odour may form some objection to its adop- 
tion in close plantations adjacent to dwel- 
lings; but it possesses the additional pro- 
perty, of keeping off cattle from the bark of 
young timber or other trees, as well as 
checking the formation and progress of in- 
sects. It is therefore well worthy of trial 
in all young plantations where any diseased 
trees make their appearance. 
