BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. 4] 
last emergence was made by a weevil placed in the hibernation cage 
on December 1. The dates on which 25, 50, and 75 per cent of the 
weevils had emerged follow very closely the sequence of installation. 
TABLE XVIII.—Hibernation of the boll weevil in open field cages, winter 
1918-19. 
Nee 
ber 0 
Cage Date A 
No. |started. eae 
stalled. 
1918. 
5 Leesa Oct. 1] 1,000 
Awe oars Oct. 15} 1,000 
eee Nov. 1} 1,000 
AQE See Nov.15} 1,000 
AB as Dec. 1 300 
Total 4,300 
PA ae al| Mite me ls 860 
Mass. Sasa ee ' 1,000 
DIVE pat | rcs! 300 
Date of | Date on | Date on | Date on|,. 3,4) Numberemerg- | Per- 
las which | which | which at ing. cent 
x 25 per _| 50per | 75 per i! age o 
cence, [cent had|cent had|cent had Pane Fe- sur- 
8 emerged.|emerged./emerged. SeNCe \ales males Total.|vival. 
1919. 1919. 1919. 1919. |Days. 
Mar. 16 | Feb. 20 | Feb. 20 | Mar. 16 DATEL 1 2| 0.2 
.| May 27 | Mar. 1} Mar. 8} Apr. 2 96 | 17 21 38! 3.8 
June 2] Mar. 7} Apr. 2} May 6] 102 | 23 22 45) 4,5 
June 1 | Mar.16 | Apr.17 |...do...| 101 | 68 59 1D alin Dy | 
June 5 | Apr.1l ay 4] May 10 87 | 14 9 23) || 275.6 
FASO eRe SS eal Ce ene ots Seer Ons 410 123 {112 7B) oasGas 
Bei tersiets ial| Clee sara totarell tole ere ya [ye eee oT raat de 82 | 24.6 | 22.4 47 | 5.76 
erate tevayate vei| sfajavaiereveie | eis aye ate cl [ ere ayer ea eee eye 102 | 68 59 127 | 12.7 
Beer aaa erates steps ial eeieiatawr ae Penveetas ses] ee soci ae 24) 1 1 2 2 
NUMBER OF BOLL WEEVILS SURVIVING THE WINTER WHEN HIBERNATING ON 
THE GROUND IN THE WOODS. 
Woods shelter has always been considered one of the ideal places 
for successful hibernation of the boll weevil. The results secured at 
Madison showed a total percentage of survival of 12.8 as compared 
to 5.76 per cent for the open field. The results of the woods hiber- 
nating experiments are presented in Table XIX. In every case the 
emergence started from the cages on February 20. The cage in- 
stalled October 1 gave the smallest percentage of emergence (0.8), 
while the cage installed November 15 gave the highest emergence 
(20.7 per cent). 
TABLE XIX.—Aibernation 
records of adult boll weevils in cages on ground in 
woods. 
Num- Date on} Date on| Date on - Number emerg- | Per- 
per of | Date of) Date of | Which | which | which |Petiod ing. F cent- 
Cage Date el first last 25 0 o of f 
No. |started.| “°'"S| emer- | - emer- per | oO per | 75 per |emer- pace 
in- ance ence, (cent hadjcent hadjcent had) > oo. Hoe | sur- 
stalled.| 8 8 - lemerged.jemerged.|emerged.|® |Males males| otal. vival. 
1918. 1919. 1919. 1919. 1919. 1919. |Days. 
Dink tee Oct. 1| 1,000 | Feb. 20| Apr. 2] Feb.20| Feb.26| Mar. 4] 41 Lue Sil. O88 
Sy ete Oct. 15} 1,000 |....- do..| June 17 | Mar. 4 | Mar.16| Apr. 5 117 19 22 41 4,1 
Seen ce INOWASTIED O00) 2222 © do..| June 1/ Apr. 4| May 6| May 7] 101) 115 81 | 196} 19.6 
ean ee IN Oil 5 el 0008) L552 do..| June 8 | Mar. 5 | Apr. 2} Apr.28|] 108] 113 94) 207) 20.7 
VA te lee Decialie 300s iss = do..| June 16) Mar.12} May 7] May 7] 116 30 | 27 of | 19.0 
Mo tales |teceesest Ae SCN) aera ce | ME Meat RIN eipateer ie ep Mag Ph ASS TOR Te ls 298e e509) aera 
SAYS Suet 3G sree SOO) RR ee: EAB Epi one: LE ei yk RRL A IR Uae MILLE a 96.6 | 56.2 | 45.6 |101.8 12.8 
Meader as eee ae LE OOO UIE Racer melee ien wee alinen vn Sulit otee yen ee 3 US ok 1207 20.7 
Mine sss. KOU) ae Aes NS Bee eee, gee ee |e De Oe oe | en eee 41 4 | 4 8 0.8 
