The National tribune., 1888-05-03
rnr Sale MOTIF.

TIE SCALE MOTH.
Thesutbor referred f rst TO the White or Fluted
scale icOrya purchase blaskel), large scale
insect family Coccdael Ii was probably IN
troduced into California from Australia 10 1868,
by the late George Gordon Of Aenlo Park, on
plants OF Acacia latiioiia. Prof. Riley had, by
study Ia California, been able 10 add oousider-
able 10 the knowledge Of the lite-hIstoTy OF
Ehis insect especially the characteristics Of the
male. The species had proved extremely hardy,
being able 10 exist q long time without IoGc.
il is quite polyphag0as lomniyerOusj, but
EhriVss best GA acacias, lime, lemon, orange
ounce, pOmcgranate and walnut. lie spoke CT
Its manner Of spreading by being carried long
distances BIS currents OF wind, In running water,
by either insects aud birds also on clothing OF
persons and in packages. ID wasg quite important
IS throwing light upon the original haeitat q
tbs species 10 determine Whet her 4cOTyS purchase
RBC /. sacchari were net Identical the latter
being native Of the islands of MauTitius and
BOURBON. This question he had been able 70
settle the past Autumn while in Paris, by cot0-
pairing the types in DR.. SIgnOret's collection
proving them 10 be good and distinct species.
This confirmed his opinion that /. purchase
was native Of Australia. A long list OF Ple-
d&Ceous and parasitic insect enemies was given,
and the Important fact pointed out that in Aus
tFslis this species was comparatively harmless,
and its Tayages in California would cease IN
proportion as its insect enemies could DO IN
troGuced.
TIE HESsIAN FLY.
The second species treated Of was the Eessisn
hy family Cecidomyia destruct0r, say. II has
recently attracted much attention IN England,
where il WAS introduced some two years since.
Ii has long been known on the continent of
Europe sad 30 this country; the popular be-
lief 5eicg that it was introduced here during
the Revolutionary war. la England II has
siTtady spread along the eastern coast and up
into Scotland. In the United States during
the past century il has constantly extended its
ravsgcs westward with the spread Of wheat
culture until now 1t has permanently oocG-
pied the entire wheat growing area, with the
exception Of portions of the northwestern and
southwestern limits. Its advent in England
az this late day has greatly exercised British
agriculturists aud the public generally.
Prof Riley mentioned three points Of special
interest, VIZ, the date Of its introduction into
England, the country from which it was in
troduced, and its probable future injuries. He
hGs found by : study of the parasites intestiug
it ia England, that they are all essentially
European, and indicate its introduction from
the continent, as also does the indirect evidence
We possess.
The third insect mentioned was
TIE hop PLANT-LOUsE
(Phorodon humuli, Sehr) OF this he stated
that its lile-history has for the first time been
fully worked CUT the past year, aud the tact
clearly settled that it hibeTnates in the Winter
egg on species OF plum. either cultivated or
Wild. This has been indicated by observations
Of some CT the early writers, but never fully
settled
De gave the following summary Of its life
history: Tie Winter egg hibernates On species
Oi pruDus, from which IL Spring is Matched Al
aEauIie female known as the stem mother. Two
the piuIa, the last Of which acquires wings and
migrates 70 the hopgarls. Here successive
generations of wingless agamie females are pro
0uced until winged individuals again appsar
and instinctiTeiy return 70 the plum. The FIRST
OF the return migrants are agamic females, aud
produce on the plum but three to five young
which arc the true females and wingless. The
winged lnales are produced about this time On
the hDp-RIle, and dying 10 the plum trees pair
with tse wingless females which then deposit
Cd the 5WiCs The Winter eggs. Remedial meas
ures Should consist ia destroying the eggs or
yOHng after they hatch upon the plum in
Spring, and IA treating with washes the infest-
ed hop plants. There czA be no infection frCm
b0Pyard 70 hopyard; hence the problem Is
much sim pliled. The author concluded as fol-
lows:
All three Of the species which I have
brought 20 your notice have been imported TO
this country from other countries and this is
the case with the vast majority OF the worst
weeds and insects Of American agriculture. !
should naturally be led, in closing, to some con
siderati0ns growing out OF this Interesting fact
for il is noteworthy that such introduced spe-
cies oftsn. aRd inGeed Is q rule,
oUTsTRIP TIE NATIVE SPECIES
IN the struggle for existence, and become al
normally destructive to cultivated crops. In
America and the other newer, but, geoloeicaliy
speaking older, parts OF the world, as Australia
one reason for this state Of things is patent
viz, the fact that tie natural enemies OF the
species are. as a rule, not brought with it, 81
that il has mach freeT play in It's reproductive
powers than il has IN It's native country, where
such natural clerks OccaT. But there are othel
just Is potent facts which tend 10 bring about
the greater destructiVeuess Of introduced spe
cies IN tie countries mentioned, and one tba
has not been fully realized has always STRUCK
me with much force. Ii is this, that NEST o
such species are introduced from Europe or tht
older civilizations, where, on evolutionary
grounds it Is natural 10 suppose that they ar
they very species that have become accustomed {,
the civilized conditions induced during 60 Ilan1
centuries II other words, the species whicl
most abound and have most successfully accom-
mOdsted themselves 10 such arti fetal condition
have 10 the ge0logcaily brief period Of man
pre-emiDence, acquired advantages over specie
that have not been submitted to such eYiron
menE The former when brought into cOmpe
titiOn with the latter, under such conditions
rapidly OUtnumber them aud get the upper
hand"
q