Bugs, Cicadas, Aphids, and Scale-insects 177 
ing region of any importance in France, or elsewhere, exempt from 
phylloxera.” 
Curiously enough this native American pest came to California, in which 
state it has done much more damage than elsewhere in our country, from 
France, introduced on imported cuttings or roots. It was first noticed about 
1874; by 1880 vines had been killed by phylloxera in three counties and 
hundreds of acres had been pulled up in the famous Sonoma Valley. 
Since then the pest has spread, according to Bioletti, to all the important 
grape-growing regions of central and northern California, and probably not 
less than 30,000 acres of vineyards have been destroyed. 
The phylloxera appears normally in four forms: (1) the gall form, living 
in little galls on the leaves, and capable of very rapid multiplication (this 
form rarely appears in California); (2) the root form, which is derived from 
individuals which migrate from the leaves to the roots, and which, by its 
piercing of the roots, sucking the sap, and producing little quickly de¬ 
caying tubercles on the rootlets, does the serious injury; (3) the winged 
form, which flies to new vines and vineyards and starts new colonies; and 
finally (4) the sexual forms, male and female, which are the regenerat¬ 
ing individuals, appearing after several agamic generations have been 
produced. 
The life-history of the pest has been described as follows by Bioletti: 
“Some time during the summer, usually in July or August, some of the eggs 
laid by the root-insects develop into insects of slightly different form, called 
nymphs. They are somewhat larger than the normal root form and show 
slight protuberances on the sides, which finally develop into wings. These 
are the winged or colonizing insects, which emerge from the soil and, though 
possessing very weak powers of flight, are capable of sailing a short distance, 
and if a wind is blowing may be taken many rods or even miles. Those 
which reach a vine crawl to the under side of a leaf and deposit from three 
to six eggs. These eggs are of two sizes, the smaller of which produce males 
and the larger females. The female, after fertilization, migrates to the 
rough bark of the two-year-old wood, where she deposits a single egg, called 
the winter egg, which remains upon the vine until the following spring. 
The insect which hatches from this egg in the spring goes either to the young 
leaves and becomes a gall-maker, or descends to the roots and gives rise to 
a new generation of egg-laying root-feeders. The normal and complete 
life-cycle of the phylloxera appears then to be as follows: Male and female 
insects (one generation in autumn); gall-insects (one to five generations 
while the vines are in leaf); root-insects (an unknown number of genera¬ 
tions throughout the year); nymphs, which become winged insects (one 
generation in midsummer). The gall stage may be omitted, as it generally 
is in California, and the insects which hatch from the fertilized eggs laid by 
