176 
Journal of Agricultural Research 
Vol. XXXI, No. 2 
stage. The head and thorax and appendages can become complete, 
but the abdomen usually remains cream-colored, the insect dying at 
that point. 
Unemerged adults show another phase of this condition. Nor¬ 
mally the emerging beetles cut clean circles in the epidermis of the 
bean, but the treated unemerged adults lose the capacity to do this 
and endeavor to emerge by pushing through the center of the circle. 
They are found dead with part of the mouth parts showing through. 
In the upper limits of the zone of arrested development adults will 
continue development quite normally if assisted out of the bean. 
The effect here, then, seems to be an inhibiting of the normal response 
of the insect, resulting in death by imprisonment. 
EXPERIMENTS ON TEMPERATURES FATAL TO B. OBTECTUS 
Table III gives the results of experiments on the several stages, and 
following it are Figures 4, 5, and 6, in which the data of the experi¬ 
ment have been incoiyorated. The table has been condensed, but 
all the data are given in the figures. 
Table III .—Limits of fatal temperature-time zones of Bruchus obtectus 
ACTIVE ADULTS 
Temper¬ 
ature 
Time 
Result 
Temper¬ 
ature 
Time 
Result 
°C. 
Hours 
°C. 
Hours 
-2 
168 
Lived. 
1 
8 lived; 13 killed. 
f 24 
Do. 
2 
Muscular activity, then 
-7 
\ 36 
Do. 
death. 
l 48 
1 lived. 
—14 
3 
Do. 
f 24 
Lived. 
4 
Killed. 
-8 
\ 30 
Killed. 
5 
Do. 
l 36 
Do. 
on 
2 
Do. 
-9 
1 
Lived. 
— 
l 3 
Do. 
.5 
Do. 
1 
Do. 
2 
18 lived; 10 killed. 
„ , in 
3 
Muscular activity, fol- 
1 U 
lowed by death. 
4-11 
Do. 
12 
Killed. 
13 
Do. 
UNEMERQED ADULTS 
/ 24 
Lived. 
/ 1 
Lived. 
—o 
\ 36 
Killed. 
—14 
l 2 
Killed. 
f 1 
Lived. 
-17 
24 
Do. 
i n 
1 2-6 
Do. 
_on 
f .25 
Killed. 
—IU 
1 7 
Killed. 
— M 
\ .50 
Do. 
l 8 
Do. 
PUPAE AND ADVANCED LARVAE 
-2 
168 
Lived. 
/ 1 
Lived. 
24 
Do. 
— 
\ 3-9 
Killed.® 
36 
Do. 
17 
J 24 
Do. 
-8 
48 
1 lived. 
1* 
t 36 
Do. 
56 
Killed.® 
.5 
Lived. 
60 
Do. 
an 
2 
Killed. ® 
-9 
1 
Lived. 
4 
Do. 
1 
Do. 
6 
Do. 
3-7 
Do. 
8 
Killed.® 
-10 
9-16 
Do. 
22-23 
Do. 
25-30 
Do. 
32-34 
Do. 
• Cases where death followed post-freezing development. 
