40 
THE GEAPE ROOT-WORM. 
Table XVII. — Time of transformation of larvse and pupse of the grape root-ivorm in 
the field, as observed in the vicinity of North East, Pa., 1909. 
Vineyard. 
Date 
exam- 
ined. 
Number 
of vines 
exam- 
ined. 
Number 
of larvje. 
Number 
of pupa?. 
Number 
of beetles 
in cells. 
J. D. Curtis's 
vineyard, 
porous silt. 
June 12 
June 21 
June 25 
June 30 
July 6 
July 10 
286 
6 
2 
2 
32 
47 
54 
4 
7 
6 
6 
6 
6 
2 
24 
4 
O.E. Pierce's 
vineyard, 
gravel soil. 
June 11 
June 21 
June 25 
June 30 
July 6 
July 10 
101 
5 
5 
49 
13 
12 
6 
6 
6 
7 
6 
3 
V ineyard , 
loamy 
soil. 
June 23 
June 25 
Jane 30 
July 7 
July 10 
July 17 
I 
6 
6 
6 
A 
O 
3 
1 
1 
1 
24 
5 
17 
2 
1 
2 
2 
1 
W h it man's 
v i n e y ard, 
clay soil. 
June 23 
June 25 
June 30 
July 7 
July 10 
July 17 
July 26 
6 
6 
6 
6 
6 
6 
6 
1 
1 
1 
1 
6 
5 
2 
1 
1 
It is possible to establish the time of pupation by knowing the time 
of emergence of the beetle and the length of time of the pupal stage. 
Judging by the late emergence of the beetles, August 9, and by the 
finding of beetles in cells in the field August 14, pupae must have 
occurred up to the end of July. Based upon these records the curve 
of figure 23 has been constructed. 
DURATION OF THE PUPAL PERIOD. 
The pupal stage on an average lasts 17 daj^s (see Tables XV and 
XVI). The maximum length of time observed was 21 days and the 
minimum 12 days. 
LIFE CYCLE OF THE GRAPE ROOT-WORM AS DETERMINED BY 
REARING. 
Several attempts were made to rear this insect from eggs, and to 
carry it through the different stages to complete the life cycle. In 
the course of these experiments many failures occurred. The mor- 
tality in certain experiments was high; in other instances a large per- 
centage became materially delayed in development and the larvse 
wintered a second season, and only a small number completed the 
life cycle within one year. (See Table XX.) The records from these 
latter observations are given in Table XVIII, with dates of hatching 
in 1908 and the dates of reaching maturity the following year. 
