The Providence news. (Providence [R.I.]) 1891-1906, 1899-07-06
GALL INSECTS.
How They Make Material for Various Inks
and lIas.

Oak apples. so called. are familiar OBJ
| jects TO almost every one. yet few un-
| derstand their real nature. Many per-
sons suppose them TO be sort Of fruity
growth OF the tree on which they are
found. Besides the oak apples. there
are similar swellin2s and fruit like
growths. some OF which are attached
10 twigs and are larger than cherries.
while others grow on leaves and are as
large as a hens egg. but OF more
grobular form. Some are hard within.
some soft but woody i'm texture; others
are pithy or spongy. and still others
are nearly hollow, with strings on fibers
radlating from the center.
All kinds have in the middle = small.
hollow, pea-shaped or seed-like cell,
which contains the insect that Is the
real cause Of the growth. The Irritation
to the leaves or twigs caused by these
tiny Insects gives these abnormal
growths the distinctive and appropriate
name Of gals" by which they have
long been known, says the Philadelphia
Times
Gall flies are among the most pecu-
liar of all the insect tribes. They be-
long TO the great order that includes
the bees. the wasps. the gnats. and the
ichneumon fiies, but they never sting or
harm men or animals. The female gall
ny, lmpelled by the law Of nature 10
provide for the safety and welfare OF
her offspring. cuts away the outer skin
or bark OF leaf or twig, and deposits
therein an egg. From this is Matched a
small white grub. without legs, but
with strong gnawing mouth. As it
eats It's way into the surrounding It's
sue the plant is seemingly invigorated.
ana begins To enlarge about the tiny
larva and grow into shape well suited
To its needs as "A place OF concealment
and food supply. While all flies of the
same species develop gall that are ex-
actly alike, every species produces
diherent form. Exactly why this is so
has never been explained, yet we see
parallel instances everywhere in ma
ture.
When the larva is fun grown IL is
transformed in it's narrow cell To a
rey-eyed. whitish pupa, helpless and
almost motionless, yet having rudi- |
mentary antennae. legs and wings. |
which gives promise OF the coming gall |
fy. This, in many species. is a gayly |
'olored insect. with red eyes. more or |
ess veined wings, a bumped back, and I
IN exceedingly long oYipositor. Thus /
IL energies from it's confine-
nent and flies abroad. soon TO deposit
Us eggs i'm leaves ana twigs and thus
o cause other gals.
Yet, strange to say. the successive (
enerations OF the same species differ
.ldely IN appearance and even in color |
rom gals made by the spring brood
re Matched flies OF the summer brood.
nose grubs winter in the gals and
fouuce the brood of the following
pring. Not only do these successive
enerations differ in appearance. but
ne summer brood consist OF both sexes.
ME the spring brood is of females
MY. In some species one brood is en-
rely biack, while the following one is
ighly colored.
The blackberry has a gall fly which
ives exclusive attention to that plant.
no causes hard swelling OF the stems |
He'd with several cells each occupied |
grub. i think the Eight O'Clock
: would lind II interesting TO gather
'Ihe OF these curious gals. selecting
lose that have turned brown. which |
rows that they have attained full
'owth. III they are put into a recepta-
e that VIII admit "a little light and
r. out VIII not allow the gall fy 10
cape, the process OF Matching out NAV
observed, after which the prisoner
ay be liberated. The flies are often
autilulIy colored. some with red and
ack bodies, others with metal0o 8
cen or blue reflections.
OAK gals are either spongy or woody. :
he former are OF no value TO man. but
e latter are largely used in the manu. |
cture OF INKS and dyes. This is due TO
tact that they contain a large per- n
ntage OF tannic acid, and when com \
ned with certain salts OF iron form =
ack, dark brown. or purple dyes. OF :
peFmsnent color. In our A
untry gals adapted TO commercial
rposes cannot be found i'm sufficient Il
ana tiles 10 supply the demand. THE
lis exported from Aleppo. i'm syria g
: the most valuable known for the :,
'nrfacture OF inks and dyes. Ink used | =
important legal documents is re- =
ired, by the laws of England and =
ance. To be made from gals. sucb
having proved 10 be practically I'm. T
ihl0 III \