SKASONAL HISTORY. 
35 
Table XL— Field observations on the hatching of eggs of the grape root-worm in the 
valley and on the hill in the vicinity of North East, Pa., 1909. 
In the volley. 
On the hill. 
Date. 
Number 
of 
clusters 
counted. 
Percent- 
age of 
clusters 
hatched. 
Date. 
Number 
of 
clusters 
counted. 
Percent- 
age of 
clusters 
hatched. 
Julv 30. . . 
Aug. 4 . . . 
Aug. 12.. 
Aug. 19.. 
Aug. 20.. 
Sept. 2... 
41 
70 
67 
90 
103 
78 
39 
42 
70 
91 
97 
100 
July .30. . . 
Aug. 13 . . 
Aug. 19 . . 
Aug. 26 . . 
Sept. 2. . . 
Sept. 9.. 
Sept. 16. . 
48 
56 
76 
66 
97 
98 
87 
10 
40 
60 
77 
81 
92 
100 
THE LARVA. 
VITALITY OF THE NEWLY HATCHED LARVA. 
On hatching, the minute larva drops to the ground and makes its 
way to the roots of the vine through cracks and crevices in the soil 
and by burrowing. In this struggle to reach the food supply there 
is probably always a high percentage that perishes, for the number of 
eggs deposited is much larger than the number of larvae found Later 
in the ground. 
The power of the young larva to exist for a time without food, 
however, is remarkable. In the breeding of the insect a number of 
newly hatched larva?, confined in a glass tube, were kept alive for 8 
days without food or moisture. Interesting experiments showing 
the burrowing and traveling powers of the young grub were carried 
out by Dr. E. P. Felt in 1902. This gentleman found that one larva 
had traveled a distance of over 47 feet in 7 hours, or an average of 
6 feet an hour. In another experiment he found that 14 young 
larvae out of 40 penetrated through loose earth in a glass tube 17 
inches long in a period of 4 days. This tube was one-half inch in 
diameter and bent so that 4 inches were vertical. In our breeding 
cages young larva 1 were found to feed upon the humus of the soil 
before reaching the root fibers: therefore it is not surprising that 
many larvae do penetrate to the roots, even under unfavorable con- 
ditions, and that they are found in vineyards in compact clay soil. 
FEEDING AND DEVELOPMENT OF THE LARVA BEFORE WINTERING. 
During the summer and until late fall the larviv feed extensively, 
and on an average attain three-fourths the full size and frequently 
full growth before wintering. 
The young larva feeds mainly upon the finer routs and root libers 
of the grapevine. Later it attacks the larger roots, devouring the 
bark in longitudinal furrows, as shown in Plate III. Sometimes the 
