86 
APPLE AND PEAR TREES DESTROYED BY THE LOCUST. 
line of bristles will be thin ; let them be stiff, about 
one inch long, make 16 arms, and if no dead air 
created by speed, give the brush six or seven revo¬ 
lutions to the arc of the saw ; give the saw about 
200 revolutions in a minute, and I think a sixty 
saw gin, in clean cotton and that has lain in bulk well 
pressd, having been thoroughly dried before putting 
up, will gin 2| bales of 400 lbs. each. As Mr. 
Abbey says, “ the brush is one of the most im¬ 
portant things about a gin-stand”—so say I, and I 
agree with him, give it all the motion that is safe, 
and that will give draft enough. By givi ng motion, 
each wing or brush will clean fewer teeth, and will 
blow it apart from the compression it received in 
passing into the tooth. 
I would add another thing. The mote board should 
be constructed so as to allow it being dropped low, 
or raised; when the brush is going rapid, and the 
mote board too narrow, there is much cotton wasted 
with the motes. It seems to me, that, in giving a 
brush velocity, there should be drivers on each end 
of the saw cylinder, so as there need not be so much 
tension on the band, which causes too much pres¬ 
sure on the gudgeon ; consequently friction, wear, 
and heating, if there were bands at each end, of 
course there would not need be so much tightness 
in the bands. M. W. Philips. 
Edward’s Depot, Miss., Oct. 25th, 1846. 
APPLE AND PEAR TREES DESTROYED BY 
THE LOCUST. 
The Seventeen-year Locust (Cicada septende- 
cim ) has heretofore been considered by horticul¬ 
turists as harmless, or nearly so ; but from the fact 
of their burrowing into the earth the moment of 
their escape from the egg, and living for seventeen 
years amongst the roots of trees, and nowhere, else, 
I was led to believe that the failure of fruit, par¬ 
ticularly the pears and apples, was mainly owing 
to these countless swarms draining the sap from 
the roots, and thus rendering them unable to supply 
the branches with sufficient nourishment. I was 
confirmed in this opinion by an experiment made 
by J. B. W., of New York, and published in the 
Horticulturist, November number, page 227, to 
which I refer you. The method there prescribed, 
<c to renovate an out cast,” is to dig a trench four 
feet wide, and twenty inches deep, around the tree, 
leaving a ball of earth six feet in diameter, and then 
to fill the trench with rich earth and compost. The 
author states that the experiment succeeded, and 
that in three years the tree was in a flourishing con¬ 
dition and again yielding fine fruit. The writer at¬ 
tributes the change to the new and rich soil with 
which he supplied the tree, while I argue that in 
destroying the larvae of the locust, which he did 
when he cut off so large a portion of roots, he re¬ 
moved the real disease, and the tree was then in a 
condition to take advantage of the congenial soil 
placed around it, and new life was given to the 
roots and branches. 
Under this impression I superintended a similar 
experiment on a tree that had been declining for 
years without any apparent cause, as there, were no 
insects on the tree, and the roots had been amply 
supplied with manure. Agreeably to my expecta¬ 
tions I found the larvae of the locust in countless 
numbers, clinging to the roots of the tree, with 
their suckers piercing the bark, and so deeply and 
firmly placed, that they remained hanging for half 
an hour after being removed from the earth. From 
a root a yard long and about an inch in diameter, 
I gathered twenty-three larvse ; they were on all the 
roots that grew deeper than six inches under the 
surface, and measured from a quarter of an inch to 
an inch in length. The roots were unhealthy, and 
bore the appearance of external injury arising from 
small punctures, and on removing the skin of the 
bark this appearance increased, leaving no doubt 
as to the cause of the disease. The larvee were 
enclosed in compact cells of earth, with no outlet 
except that in immediate contact with the roots. 
As there were no galleries or holes leading from 
these cells, 1 infer that the grubs never leave the 
roots they first fasten on, which may account for their 
great difference in size, the small ones being starved 
specimens of the same brood. 
Though this curious insect has afways made its 
appearance at stated intervals over our broad land, 
few appear to be acquainted with its history and 
destructive habits, all believing that the only injury 
received from them, was while depositing their 
eggs on the branches of the trees; but if we trace 
them through their various changes to their subter¬ 
ranean home, we will find them a destructive and 
insidious foe, robbing us slowly but surely of our 
fairest and most valued fruit. This insect is not 
a true locust, but derives its popular name from its 
fancied resemblance to the locust of the East, which 
belongs to the family of grasshoppers ( Locusta ). The 
Cicada septendecim appears in June every seven¬ 
teen years. When they emerge from the ground 
they are grub-like in form, destitute of wings, and 
covered with a tough shell, a proper and most con¬ 
venient coat, that effectually protects them while in 
their earthly abode. The evening and early 
morning hours are best suited for them to undergo 
their change, and accordingly as soon as the sun 
disappears they may be seen creeping from the 
earth in countless numbers, crawling to the near¬ 
est tree or shrub, which they climb until they reach 
a convenient spot to grasp firmly. There they 
await the change, which begins by a slit opening 
in the hack of the shell, and the fly gradually draws 
itself out, the body enlarges, the wings expand, and 
the creature assumes new life and energies, though 
it always continues heavy and rather sluggish. 
They live in the winged state three or four weeks 
before they deposit their eggs, subsisting on dew 
and moisture on the leaves of the trees. The 
female has a strong and curiously contrived piercer 
with which she carefully slits the bark of the twigs 
of trees and shrubs, and deposits her eggs in pairs, 
side by side, but separated by a portion of woody 
fibre, and placed obliquely so as to allow one end 
to point upwards; from ten to twenty eggs are 
deposited in this slit. She then removes to a little 
distance and makes a new nest, when a limb is suf¬ 
ficiently stocked, she removes to another, until her 
store of eggs is provided for, vrhen she becomes 
exhausted, falls to the ground, and soon dies. One 
female will deposit four or five hundred eggs. 
The eggs require forty-two days to mature in the 
branches of the trees; they then burst the shell and ap¬ 
pear a minute but active fac-simile of\ the parent in 
the larva state, requiring but a few moments to stretch 
