28 
. 
BUSHBERG CATALOGUE, 
dividuals, under certain conditions, abandon their nor- 
mal underground habit, and form galls upon the leaves 
certain varieties of eapkesitenn we a in a general 
y, the natural history of the spe 
The annexed figure shows the anil swelling of 
ee — beyond, until 
hens rally wastes away. 
ring he first year = attack there are scarcely any 
outward manifestations of disease; only the second and 
third year—when the fibrous roots have vanished, and 
th n rmatioi 
lor arance oi the leaf, and 
e vine dies. When vine is about dy- 
ing, it is oo impossible to - the cause of 
the death, the lice having previously left for fresh pas- 
ae " 
is frequently ut ease with injurious insects, the 
ote shows a preference for and thrives best on 
certain species, and chive? diseri ee between 
ties, or what amounts to the e thing, mii 
some oe or varieties, causie its attacks and 
relative immunity from i‘s injuries. A k caeitdes a 
rane relative susceptibility of different varieties to the 
and i ct, is therefore of para- 
Information on this subject, based 
lone iananitiaee: 
a 
2 
{fvPr a healthy b, 
ae ages the age are. pe Bora asin repeesan ting. "the Knots and 
swellings caused z — unetures;¢, a t that has 
been deserted _ ere tentiets have com- 
/ pe stngenndingronaey fs a, ret g ow eee ve are rn 
ge jew. ] Du as 
on the researches of Prof. Riley, in addition to careful 
observation and experiments, made duri 
alogue, both in the “ Dectiptic 
s to Dr. Engelmann’s * eciatibation of Spe- 
i. bee 4—12.) 
he reasons why certain vines thus barged exemption 
while hase so readily succumb, cannot be fully ascer- 
tained, but in a broad way it may be stated that there 
is a relation between the susceptibility of the vine and 
the character of its roots—the slow-growing, more ten- 
der-wooded consequently tender-rooted varieties 
Merrie. the nai readily. 
We see in the general resistibility of our purely na- 
ri vines n e Phylloxera, a remark- 
able verification of that law h in has so ably 
established and pesmi § expressed, as “* THE SUR- 
VIVAL OF THE 
TTEST 
Professor Riley, in explaining “ Why the insect is 
“* There 
nine the attacks of the —_— 
the contrary, succumbs mor 
of its more tender and cue n 
has not been a is ae to the ps 
known fact that diseas so paras 
paratively harmless st peoples long accustomed to 
them, become viru} ften fatal when first intro- 
duced among h 0 uncontaminated peoples 
keep it within due oo are lacking in Europe; and 
e before the closely allied Kuro- 
pean predaceous a will prey upon and check it 
there to the same € extent. ress Phylloxera will, also, 
all other thi 
counixics where the 1 Ae ae and shortness of the min- 
hylloxera, in both types, is aeand 
on our wild vines, it is very doubtful if such wild vines 
in a state of nature are ever killed by ing With their 
ing arms embracing shrub tree, their 
oe habit unchecked by the ee knife, these 
s have a correspo 
anid render 
more nearly these n 
employed in the ravaged French 
districts, where the ee are grown in greater proxim- 
ity and allowed to trail upon the ground, or are sup- 
ported to a single io mane. id 
Again, aft 2 of the] I ft wi 
win Asset 
fall, he adds the tollowing cogent re 
number of the New York Tribune: *‘The winged 
Phylloxera is wafted about, and et aps her a or, 
in other words, deliver herself of y, wher- 
ever she happens to settle. If this 3 upon hi 
vine, well and good—the young live and propagate, nag 
y, 
