6 
BULLETIN 911, U. S. DEPARTMENT OE AGRICULTURE. 
FEEDING PERIOD OF SECOND -BROOD LABYM IN REARING CAGES. 
Records from the date of hatching to the date of cocooning were 
secured froni 51 individuals as shown in Table VI. 
Table VI. — Feeding period of second-brood larvae of the grape-berry moth in rearing cages, 
Sandusky, Ohio. 1916. 
Date of hatching. 
Date of 
eoeoon- 
ine. 
Aug. 11 Aug. 
Do ; Sept 
Do . . ! Sept 
Do 
Sept. 7 
Aug. 13 Aug. 
Do ; Sept . 
Do Sept . 
Do R* 
Aug 
Do. 
Do. 
Do. 
16. 
Do..... 
Do 
Do 
Do 
Do 
Do 
Sept. 5 
Sept. 6 
Do 
Total. 
Average 
Maximum. . 
Minimum.. . 
. tept. 
. Sept. 
. Sept. 
.! Sept. 
■ Sep*- 
. Sept. 
. Sept. 
. Sept. 
. Sept. 
. Sept. 
. Sept. 
. Oct. 
. Oct. 
. Oct. 
cocoons. P enod - 
Days. 
* 20 
21 
26 
27 
18 
21 
22 
24 
27 
29 
30 
16 
19 
24 
25 
26 
27 
29 
36 
33 
36 
24. IS 
36 
16 
Days 
40 
105 
104 
27 
18 
42 
22 
96 
108 
58 
30 
48 
95 
72 
75 
78 
81 
29 
36 
33 
36 
1,233 
The average length of the feeding period for the 51 larva 1 was 24.18 
days, a much shorter period than has previously been recorded as the 
average for the second brood. This shortening was due no doubt to 
the unseasonably warm weather that prevailed during August, 
September, and early October of 1916. This figure should not be 
taken as representing the usual condition, but is presented here to show 
the influence of a warm fall on the maturing of the larvae. The maxi- 
mum length of the feeding period was 36 days and the minimum 16. 
LENGTH OF THE PREPUPAL PERIOD. 
The length of time between the spinning of the cocoon and pupa- 
tion was recorded for 13 individuals as shown in Table YII. 
Table VII. — Length of the prepupal period of 13 individuals of the second brood of the 
grape-berry moth, Sandusky, Ohio, 1916. 
Date of spinning cocoon. 
Number 
of co- 
coons. 
Date 
of pu- 
pation. 
Number 
of days 
in pre- 
pupal 
stage. 
Total 
number 
of days. 
Aug. 31 
1 
1 
1 
2 
5 
2 
1 
Sept. 3 
Sept. 4 
!"do." .'. 
Sept. 5 
Sept. 6 
Sept. 8 
3 
4 
4 
I 
5 
7 
3 
Do 
± 
Do 
4 
Sent. 1 
6 
Do 
20 
Do 
10 
Bo 
T oral 
13 
54 
Average length of prepupal period. 4.15 days. 
Maximum length of prepupal period, 7 days. 
Minimum length of prepupal period, 3 days. 
