-12 
of the exposed portions of roots were surrounded by an inch of fine 
sand, and all inoculations were made on these exposed portions, it 
frequently happened that phylloxera? found their way to the unex- 
posed portions, so that in the winter following the inoculations 
hibernants were found in both the exposed and unexposed portions. 
The temperatures in the cages differed but slightly from those re- 
corded simultaneously 2 feet below the soil surface in the laboratory 
vineyard. In 1913-14 in midwinter, however, the former touched a 
mark about 10 : F. lower, besides being uniformly lower throughout 
December and January in both the seasons 1913-14 and 1914-15. 
During the period (August to November) in which the phylloxeras 
entered hibernation there was no appreciable difference, and. before 
the commencement of the spring growth of the hibernants the tem- 
peratures were again equalized. Thus, in the periods of entering 
into and awakening from hibernation, vineyard conditions were 
reproduced in the cages as far as temperature was concerned. Con- 
temporaneous vineyard observations show that the behavior of the 
hibernants on living vines in the cages simulated closely the be- 
havior of those in the vineyards in the locality, and the habit of 
clustering was often noted. The aphids entered into hibernation 
and showed spring activity much as they did in the vineyards, but 
in each phenomenon there was an exception. In 1911. six aphids 
out of a lot of nine individuals hatching between Augnst 21 and 26 
proceeded to hibernate. Such early hibernation with succulent food 
present is quite unusual in the field. Again, in 1911. on another vine, 
pan of a series of hibernants cast their skins as early as February 
23. indicating that growth commenced not later than February 15. 
In the vineyard, even upon warm soils, the first date of actiwity was 
never earlier than February 25. This early spring activity in the 
cages was possibly due to comparatively high temperatures in Feb- 
ruary, this being the only month during which the cage temperatures 
exceeded those in the soil. 
Hibernation on America.)-, resisfymt and nonresistant vines in cages, 
r -io. — Along with the vinifera vines planted in the special cages 
for observing the phylloxera on living roots, a number of American 
resistant and nonresistant vines were used for similar observation. 
The nonresistant varieties (propagated from Vitis labrusca and V. 
tivalis ) were Catawba. Isabella, Lenoir. Delaware, and Champion. 
The Muscadine [V. rotundifoli was used also. The resistant 
hybrids, some of which were grafted to vinifera?. comprised Mour- 
vedre X Rupestris 1202, Solonis X Riparia 1616. Berlandieri X Ripa- 
ria 157.11. Riparia X Rupestris X Aestivalis X Monticola 554.5. 
Aramon Eupestris Ganzin 1. Riparia Gloire de Montpelier, Eupes- 
tris St. George. These vines were planted in the spring of 1911 and 
inoculated thereafter. 
