THE GRAPE PHYLLOXERA IN CALIFORNIA. 
119 
In a fourth experiment 26 eggs were placed in water in a stender 
dish. Two days later all but four eggs had sunk, but subsequently 
all eggs hatched and none of the resultant larvae settled on the roots 
provided for them. 
Table XXXVI indicates the results of experiments bearing on the 
behavior of newly hatched larvae in water. 
Table XXXVI. 
-Behavior in water of newly hatched, larvw of the grape 
phylloxera, Walnut Creek, Calif. 
Date 
Number of indi- 
viduals 
that— 
Length 
of sub- 
mersion. 
Number of indi- 
viduals after 
submersion. 
placed 
in water. 
Sank. 
Re- 
mained 
on 
surface. 
Alive. 
Dead. 
Remarks. 
May 12 
12 
27 
15 
19 
June 1 
May 24 
June 1 
16 
16 
1 
July 15 
15 
5 
4 
2 
4 
'5 
4 
1 

5 
5 

6 
6 
3 
2 

2 
1 
2 
1 
4 
1 
2 
4 
2 
2 
Days. 
1 
2 
2 
3 
3 
4 
5 
6 
7 
7 
9 
4 
4 
8 
6 
2 
2 
1 
1 
3 
5 

1 
8 
8 



4 
5 
5 
1 
1 
1 
7 
3 


In stender dish without cover. 
In small vial— uncorked. 
Do. 
In small vial — uncorked; sunk aphids dead. 
Do. 
In small vial — uncorked; sunk aphids alive. 
Do. 
In small vial— uncorked. 
In small vial— uncorked; sunk aphids alive, but 
none subsequently fastened on root. 
In small vial— corked. 
Do. 
In small vial— corked; one aphid subsequently 
matured Aug. 12 on severed root. 
In small vial— uncorked; one aphid subse- 
quently matured Aug. 11 on severed root. 
Note.— In all except the first experiment, distilled water was used; in the first experiment, tap 
water. 
Prior to June 16 the phylloxeras were not followed up after 
their submersion to see whether they would fasten to the pieces of 
roots provided for them because the experiments were made only 
to ascertain how many of the larvae would be alive after submersion. 
It may be noted that in some cases the larvae which sank were found 
to be alive when removed from the water and in others those that 
floated were living when removed. The phylloxerae survived as 
many as nine days on the surface of the water, and as many as 
seven days when submerged, and at the bottom of the vial. The 
experiments, however, did not continue beyond nine days, and there 
is no reason to believe that the insects could not live in the water 
many days longer than that period. The fact that they did survive 
as long as a week was sufficient evidence of the importance of their 
resistance to water. The two experiments of July 15-19 demon- 
strated that after four days in water the young larvae could settle 
on pieces of roots and later mature. In the seven-day experiment, 
none settled on the roots. In all except one of the vials distilled 
water at about 64° F. was used. The behavior of the young phyl- 
loxerae in water was characteristic. Those on the surface were active, 
