7 
broods year after year, as in the case with European vines, on the 
leaves of which galls rarely occur. Under exceptional circumstances 
all of the different stages may be passed through in a single year. 
The young from leaf galls may also be easily colonized on the roots, 
and it is probable that the passage of the young from the leaves to 
the roots may take place at any time during the summer. The reverse 
of this process, or the migration of the young directly from the roots 
to the leaves, has never been observed. 
The complicated details noted above were only obtained after years 
of painstaking research, conducted by the late Professor Riley in this 
country and many careful investigators in France. 
Means of dispersion.—The distribution of phylloxera is, first, by 
means of the winged females; second, by the escape, usually in late 
summer, of the young root lice through cracks in the soil and their 
migration to neighboring plants; third, by the carrying of the young 
leaf-gall lice by winds or other agencies, such as birds or insects, to 
distant plants; fourth, by the 
shipping of infested rooted plants 
or cuttings with winter eggs. 
By the last means the phylloxera 
ha8 gained a world-wide distribu- 
tion; the others account for local 
increase. 

REMEDIES AND PREVENTIVES. Fic. 4.—Phylloxera vastatrix. a, sexed stage- 
larviform female, the dark-colored area indi- 
cating the single egg; b, egg, showing the in- 
distinct hexagonal sculpturing; c, shriveled 
The enormous loss occasioned 
by this insect when it reached 
the wine districts of the Old 
World led to the most strenuous 
female after oviposition; d, foot of same; e, 
rudimentary and functionless mouth-parts 
(original). 
efforts to discover methods of control. Of the hundreds of meas- 
ures devised few have been at all satisfactory in results. The more 
important ones are the use of bisulphide of carbon and submersion to 
destroy the root lice; and, as preventive measures, the use of resistant 
American stocks on which to graft varieties subject to phylloxera and 
the planting of vineyards in soil of almost pure sand. 
Bisulphide of carbon.—The use of this liquid insecticide is practi- 
eable only in soils of such consistency as to hold the vapor until it 
acts on the root lice and yet friable enough to afford it enough pene- 
tration. It will not answer in compact clay soils, in very light sandy 
ones, or in soils liable to crack excessively. The liquid is commonly 
introduced into the soil by hand injectors at any season except that 
of blooming or of ripening of the fruit. Sometimes sulphuring plows 
are used, or the liquid is mixed with water and the soil about the vines 
thoroughly drenched. The great volatility of the bisulphide enables 
it to penetrate to the minutest roots, and the lice quickly perish. 
Four or five injections of one-fourth ounce each may be made to the 
