GRAPEVINE LOOPER. 
DURATION OF FOURTH LARVAL STAGE. 
The duration of the fourth larval 
stage, of 65 individuals reared, varied 
from 6 to 17 days, with an average of 
9.71 days. These data are summarized 
in Table VII. The total period during 
which larva? of this instar were recorded 
extended from June 26, when the earliest 
larva molted the third time, until July 
19, when the latest larva molted the 
fourth time. 
Table VII. — Duration of fourth 
larval stage of grapevine looper. 
North East, Pa., 1917. 
Number 
Duration 
of larvae. 
of stage. 
' Days. 
4 
6 
10 
7 
6 
8 
13 
9 
10 
10 
10 
11 
2 
12 
6 
13 
2 
14 
1 
15 
1 
17 
165 
2 9.71 
i Total. 2 Weighted average. 
Table VIII. — Duration of feed- 
ing period of fifth larval stage 
of grapevine looper North East, 
Pa., 1917. 
Number 
Duration 
of larvae. 
of period. 
Days. 
1 
7 
8 
8 
23 
9 
11 
10 
17 
11 
3 
12 
3 
13 
2 
14 
168 
2 9.97 
Total. 2 Weighted average. 
DURATION OF FIFTH LARVAL FEEDING STAGE. 
The duration of the fifth larval feed- 
ing stage, of 68 individuals reared, 
varied from 7 days to 14 days, with an 
average of 9.97 days. The data are 
shown in Table VIII. This period in- 
cludes all of the fifth stage except the 
period after spinning the cocoon, or the 
prepupal period. Records on the feed- 
ing period of larvae of this instar ex- 
tended from June 29 to July 31. 
DURATION OF PREPUPAL PERIOD. 
The duration of the prepupal period, of 68 individuals reared, or 
the time following the formation of the cocoon until pupation, is 
usually 2 days, although there are four records of 1 day and 10 of 3 
days, as shown by Table II. This variation is not significant since 
observations were made only once a day, and it would be possible 
for an individual which required a little less than two days to have 
been noted only once during that time, or for one which required 
slightly more than two days to have been noted three times. 
DURATION OF PUPAL PERIOD. 
The duration of the pupal period, as shown by Table II, was prac- 
tically the same as the preceding year, 63 of the 66 individuals under 
observation requiring 9 to 11 days, with an average of 10.18 days. 
The extremes, however, extended from 8 to 14 days. The records on 
