14 BULLETIN 926, U. S. DEPARTMENT OF AGRICULTURE. 
THE AVERAGE DEVELOPMENTAL PERIOD OF THE COTTON BOLL 
WEEVIL UNDER OUTDOOR INSECTARY CONDITIONS. 
The data on the average developmental period of the boll weevil 
under outdoor insectary conditions for sea-island and upland cottons 
are presented in Table VII. These observations extended over a 
period of time beginning on May 26 and ending on September 10. The 
maximum developmental period of any weevil from egg to adult was 
18 days and the minimum period 11 days. On upland cotton 506 
male weevils bred in the insectary required a total of 7,568 weevil 
days, or an average period from egg to adult of 14.62 days. A total 
of 347 female weevils bred under insectary conditions required an 
average developmental period of 14.8 days. The average period of 
development for the immature stages bred in upland cotton squares 
is shown to be 14.91 days. 
On sea-island cotton 150 male weevils required 2.214 weevil days 
from egg to adult, or an average developmental period of 14.82 days. 
A total of 101 female weevils, bred in sea-island cotton squares, re- 
required 1,550 weevil days, with an average period of 15.06 days for 
development from egg to adult. There is practically no difference 
in the time required for development of the immature stages of the 
boll weevil in sea-island and upland cotton squares. 
Taslte VII.—Total developmental period of the boll weevil under insectary con- 
ditions, Madison, Fla., 1918. 
| 
= Both sexes. 
) 
Aver- 
« \f 
‘ (Ge Dae y 
a 
d 
| 
/ ; Oo ozs ! age 
Source of weevils. | Sarat} ee | Aver- | Aver-|Total| Total | de- 
food. period. Nom- Wee are | NUM Wee} SS S= vel 
| ber vil SS ber) wil | ooo ee ng 
| pred_.| days. | P= | bred.| days.) P&E | Dee | vil pment- 
wear obs 3 ~"| od. | bred.| days al 
; i i | i pei 
} | od. 
See (enemies) fee Me | es Se 
| | 
Upland cotton: Days.| i Days Days 
Hibernsted...| Cotton | May 26-July 27| 201 | 2,951 |14.09 | 126 /1,812 |14.38; 327 | 4,726 | 14.4 
| square} ail 
Dp ea Bee Te | May 29-July 23) 57 816 [13.4 | 41] 564 [13.7 98 | 1,380 | 14.08 
First genera- |-..do---_- | June 14-Aug.15{ 208 | 3,183 /15.3 | 133 [2,029 |15.2 341 | 5,218 | 15.38 
tion. | 
Second gener- |_..do-.---.| July 17-Sept5.}| 40 638 15.7 47} 742/159 , 87 | 1,380] 15.8 
ation. i 
Tou.» Epes Se Dies ee 506 | 7,568 |__....| 347 5,147 |_._-..] 853 112,704 j_.___- 
Average. 2222) 2s fie = 2 2-3 eee oe ae eee 14. 62 beeen te) eee pee 1491 
Sea-island cotton: | 
Hibernated...| Cotton | May 26-July 20, 67 965 |13.5 46 689 /13.46 115 | 1,654 14.3 
| square. | 
Doses |---do....| May 2-July1§ 34) 490/144 | 15) 220/146 | 49 0 | 14.08 
First genera- |-..d0-..--. June 21-Aug.15, 33 498 15.09} 15; 249/166 | 48 746 | 15.5 
tion. i 
Second gener- |...do....| July 1i-Sept.4/ 16{ 261/163 | 25) 392/15.6 | 41 653 | 15.9 
ation. i i i 
"Total. = 22. S:s2-- 222]; So eee eee 150 12, 214))-5 = 402 13,550 |____.- 253 | 3, 743:1-.__- 
A Veraee 2 ioe Fe a ee eee ode ene 14.82 ae 55.06: | 14.9% 
