28 
BULLETIN 1428, U. S. DEPARTMENT OF AGRICULTURE 
rowing. The damage resulting from this 
habit has been previously referred to. If 
nothing better is available, the cadelle larva 
will form its cell in a hollowed-out kernel 
of corn, filling the openings with the cement ; 
or it will construct a cell out of pieces of 
grain cemented together. Finally, if noth- 
ing suitable is available, it will transform 
without forming a pupal cell. -Larvae that 
hibernate usually construct their pupal cells 
in the fall but do not transform until spring. 
Larvse that were reared in the laboratory 
were supplied in most cases with small 
pieces of cork into which they bored and 
soon disappeared from sight when ready to 
transform. After a prepupal stage lasting, 
in summer, from 7 to 17 days (averaging 
about 9 days), the pupal form (fig. 14) is 
assumed. 
THE PUPA 
Fig. 14. — The cadelle pupa. 
much enlarged. The pupa 
is seldom seen as this 
stage of the cadelle's life 
cycle is spent in a cell 
made in an inaccessible 
place. 
The insect remains in the pupal stage 
from 8 to 25 days, the length of this stage 
being influenced mainly by the prevailing 
temperatures. Table 6 contains data on the 
length of the pupal stage and the relation 
of temperature to the length of the stage., Apparently the cadelle 
does not pass the winter months in the pupal stage. 
Table 6. — Duration of the pupal stage of the eadelle 
No. 
Date 
pupated 
Date 
adult 
emerged 
Length 
of pupal 
period 
Average 
mean 
tempera- 
ture for 
pupal 
period 
1. 
1922 
July 14 
24 
25 
29 
Aug. 1 
19 
26 
26 
Sept. 27 
10 
17 
18 
20 
1923 
Mar. 27 
28 
30 
Apr. 1 
1 
6 
8 
8 
11 
24 
27 
30 
1922 
July 25 
Aug. 3 
7 
10 
15 
Sept. 1 
8 
9 
Oct. 14 
Sept. 24 
Oct. 1 
3 
6 
1923 
Apr. 16 
13 
22 
25 
23 
May 1 
1 
3 
5 
16 
17 
19 
Days 
11 
10 
13 
12 
14 
13 
13 
14 
17 
14 
14 
15 
16 
20 
16 
23 
24 
22 
25 
23 
25 
24 
22 
20 
19 
° F. 
82 
2. 
82 
3 
81 
4 
80 
5. 
78 
6. 
77 
7. - 
79 
8 
79.5 
9 
73 
10 
76 
11 . 
72 
12 , - 
72 
13 - - 
73 
14 
69 
15 . .. . .. 
73 
16 _.- .- 
72 
17 -.- _ 
70 
18 
70 
19 ■_■ . 
70. 5 
20 
70 
21 . ... .- -.- - -. . - 
70 
22 - - -- - -- 
71 
23 -- -- -- - - -- 
72 
24 - 
73 
25. --- 
73 
