PROGRESS REPORT ON THE EUROPEAN CORN BORER 89 
Table 25. — Duration of stages of Pyrausta nubilalis at Silver Creek, X. Y. 
1922 
1923 
1924 
Average 
in days 
Number 
of speci- 
mens 
Average 
in days 
Number 
oi speci- 
mens 
Average 
in days 
Number 
of speci- 
mens 
6.3 
10, 383 
6.4 
15, 307 
Larval period: 
6.18 
3.76 
5. 16 
i 13. 47 
16.92 
12.00 
64 
64 
63 
58 
13 
1 
2 28.6 to 57. 5 
Pupal period: 
13.34 
14.00 
29 
26 
Male 
- " 
Adult stages: 
9.5 
12.5 
4.1 
24 8 
22.7 
39 
39 
39 
50 
50" 
5.8 
11.3 
5.5 
22.3 
17.5 
42 
42 
42 
50 
50 
1 A majority of the larvae entered the period of winter inactivity at the end of the 
fourth instar, but certain of them developed fifth and sixth instars. 
2 Not including indefinite duration of last instar. 
In the 1923 and 1924 records pertaining to incubation and adult 
stages, shown in Table 25, 50 pairs of adults were used in separate 
cages. In the 1923 series 11 females and in the 1924 series 8 females 
did not deposit eggs. The averages for adult stages, except longev- 
ity, are based upon the number of females which deposited eggs. 
Table 26. — Duration of Pyrausta nubilalis stages at Scotia, N. Y. 
1920 
1921 
Average in 
days 
Number 
of speci- 
mens 
Average in 
days 
Number 
of speci- 
mens 
5.20 
3,567 
6.30 
806 
Larval period: 
9.00 
7.80 
6.00 
18.80 
8.50 
12.30 
15 
15 
15 
15 
6 
3 
4.39 
4.30 
4.61 
15.85 
8.50 
9.00 
97 
Second instar 
94 
Third instar . ... . 
86 
81 
Fifth instar 
38 
Sixth instar _. 
2 
Total days to last molt 2 
2 31. 6 to 52. 4 
2 27. 7 to 35. 7 
Pupal period: 
Female . ... 
12.22 
13. 17 
40 
40 
11.80 
12.40 
30 
Male 
30 
Adult stages: 
Preoviposition. . 
6.90 
11.80 
3.20 
21.90 
122 
122 
122 
122 
120 
7.90 
11.40 
2.80 
22.10 
15.70 
30 
Oviposition .... .... 
30 
Postoviposition . . . . 
30 
Longevity 9 . ... . 
30 
Longevity cf — -. . . 
14.20 
30 
Not including indefinite duration of last instar. 
See footnote 1, Table 25, 
