GRAPEVINE LOOPER. 
Table II. — Dates of hatching and occurrence and duration of stages of the grapevine 
looper, North East, Pa., 1917 — Continued. 
Number of in- 
dividuals. 
Date of 
hatch- 
ing. 
Date of 
spinning 
Dura- 
tion of 
feeding 
period. 
Date of 
pupa- 
tion. 
Dura- 
tion of 
prepupal 
period. 
Date of 
eclosion. 
Dura- 
tion of 
pupal 
period. 
Total 
duration 
of im- 
mature 
1 
June 9 
1 
9 
9 
1 
9 
9 
1 
9 
1 
10 
1 
10 
1 
10 
1 
11 
1 
11 
1 
11 
1 
11 
1 
11 
1 
13 
1 
14 
1 
15 
1 
1 
1 
1 
1 
July 20 
21 
22 
23 
26 
28 
25 
26 
27 
23 
24 
28 
30 
31 
26 
26 
27 
10 
12 
13 
15 
20 
Days. 
41 
42 
43 
44 
47 
July 21 
24 
24 
25 
28 
30 
27 
28 
29 
25 
26 
30 
Aug. 1 
1 
July 28 
28 
29 
13 
15 
16 
17 
22 
Days. 
July 31 
Aug. 2 
2 
July 24 
29 
27 
24 
Aug. 1 
Days. 
Days. 
52 
54 
54 
55 
60 
60 
57 
59 
60 
55 
54 
59 
62 
62 
57 
58 
57 
TIME OF HATCHING. 
The period of hatching of eggs in cages extended from June 2 to 
June 15, half of the larvae having hatched by June 5. These dates 
are shown in Table II. Vineyard collections indicated that a few 
larvae hatched fully a week earlier under natural conditions, for one 
newly molted larva of the second instar was collected June 2, and 
others collected in vineyards a little later were distinctly more ad- 
vanced in development than those hatched in the insectary and 
matured about a week earlier. Vineyard observations showed, how- 
ever, that the hatching period of the bulk of the brood is quite well 
covered by the insectary records. 
duration of larval feeding period. Table III. — Duration of the larval 
The duration of the larval feeding feeding period of the grapevine 
period, of 66 individuals reared, varied 
from 41 to 53 days with an average of 
46.12 days. Records of the feeding 
period extended from June 2, date of 
the earliest recorded hatching, to July 
31, date of the latest recorded spinning 
of the cocoon or pupal web. As pre- 
viously stated, a few larvae must have 
occurred in vineyards earlier than these 
records show. Compared with other 
leaf feeders on grapevines, this insect 
has an unusually long period for larval 
development, and consequently an un- 
usually long period during which it may 
be destroyed by poison sprays. 
Number 
Duration 
of indi- 
of feeding 
viduals. 
period. 
Days. 
2 
41 
5 
42 
5 
43 
8 
44 
10 
45 
7 
46 
7 
47 
7 
48 
8 
49 
4 
50 
1 
51 
1 
52 
1 
53 
166 
2 46. 12 
Total. 2 Weighted average. 
