12 
BULLETIN 807, U. S. DEPARTMENT OF AGRICULTURE. 
Table IX. — Graphic chart of life history of Bruchus rufimanus for seasons 
of 1911-18 and 1918-19. 
Jan. 
Feb. 
Mar. 
Apr. 
May. 
June. 
July. 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
Eggs, 
Larva?, 
Pup as, 
Adults, 
- 
i 
1 
1 
Continuous line=1917-18. Broken line=1918-19. 
Although a few adults may be found as late as June, the majority 
die before the end of March. During 1917 a number of badly in- 
fested beans were inclosed in a box. Ten per cent of the weevils 
were dead by February 1, 50 per cent by March, and 90 per cent by 
the 1st of April. A very few remained alive until June. The re- 
sults of field observations at Haywarcl during 1918 as to the preval- 
ence of weevils in the fields are recorded in figure 5. Each count 
represents an examination of horse-bean plants for a period of 15 
minutes. 
A7A/PCS* */*/?/£ •W7V ^/C/A/£- 
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5 
/ 
L. 
/ 
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Fig. 5. — Curve showing abundance of broad-bean weevils in a field at Hayward, Calif., 
1918. 
Adults have never been observed in the field before the latter part 
of March, but it is evident that some of them must live through the 
winter, hiding in the soil, or among rubbish, leaves, etc. In experi- 
mental plantings of infested beans, both in the fields and in pots, 
live adults have been observed to come out of the soil several days 
after planting. In one case a germinating bean was dug up two 
weeks after it had been planted, and a live weevil, which had emerged 
from the bean, was found clinging to it. In another germination 
