28 



BULLETIN 231, U. S. DEPARTMENT OF AGRICULTURE. 



By this table it is noted that normally deposited eggs developed in 

 2 days at 88.5° and in 5.8 days at 71.9°, while eggs deposited externally 

 and therefore directly exposed to the changes of air temperature 

 developed in 1 day at 77.4° and in 2 days at 86.4°. 



One weevil fed on flowers of Hibiscus syriacus deposited an egg 

 externally on September 21. This egg hatched in 4 days at a mean 

 temperature of 71.1°. 



Larval period. — Only 26 larva 3 were observed through this stage and 

 they averaged 6 days with a minimum of 5.1 days and a maximum of 

 7.1 days at a mean temperature of 84.7°. One greatly retarded indi- 

 vidual not observed to pupation required over 10 days for the period. 



Pupal period. — Only 7 observations of the pupal period were made. 

 The average period was 4.63 days, with a minimum of 4.38 days and 

 a maximum of 5.38 days, at a mean temperature of 83.6°. 



TOTAL DEVELOPMENTAL PERIOD. 



The data for the total developmental period are presented in Table 

 XVIII. Records of the development of 1,513 individuals indicate 

 a very slightly shorter period for the females than the males. These 

 various records are not strictly comparable until correlated with the 

 climatic records. 



Table XVIII. — Data on the developmental period of the boll weevil. 



TEXAS WEEVILS. 





Larval 

 food. 



Period of 

 oviposition. 



Males. 



Females. 



.a 

 3 . 



3 -a 



3"° 



o 



> 



CO 



03 



ft 



Nature of 

 weevils. 



u 

 £■ . 



1-° 





P £ 



<5 » 







S.2 

 p E 



'•a 



> 



First generation. . . 

 Do 



Cot ton 

 squares. 



May 19-31 



June 1-5 



JuneU-15 



June 16-20 



June 21-25 



June 26-30 



July 1-16 



June 17-30 



June 25-July 12 . 



Aug. 19-Sept. 26. 



July 7-10 



July 27-30 



Aug. 20-Sept. 9. . 



Sept. 9-17 



Oct. 3 



54 



72 

 57 

 48 

 27 

 36 

 33 

 12 

 41 

 13 



8 

 3 

 4 

 8 



3 



884 



1,206 

 895 

 729 

 379 

 477 

 447 

 176 

 552 

 178 



128 

 39 

 52 



133 

 56 



Days. 

 16.3 



16.7 

 15.7 

 15.1 

 14.0 

 13.2 

 13.5 

 14.6 

 13.4 

 13.7 



16.0 

 13.0 

 13.0 

 16.6 

 18.6 



50 



75 

 44 

 33 

 34 

 40 

 32 

 13 

 42 

 10 



5 

 5 

 4 

 5 

 3 

 1 

 1 

 91 



804 



1,249 

 700 

 493 

 470 

 526 

 418 

 184 

 562 

 134 



81 

 68 

 56 

 72 

 57 

 21 

 21 

 1,170 



Bays. 

 16.0 



16.6 

 15.9 

 14.9 

 13.8 

 13.1 

 13.0 

 14.1 

 13.3 

 13.4 



16.2 

 13.6 

 14.0 

 14.4 

 19.0 

 21.0 

 21.0 

 12.8 



104 



147 

 101 

 81 

 61 

 76 

 65 

 25 

 83 

 23 



13 

 S 

 8 



13 



6 



1 



3 



209 



1,688 

 2, 456 



Dai/s. 

 16.2 



lfi.7 



Do 



...do 



1,595 1 15.7 



Do 



...do ... 



1,222 

 849 



1,003 

 865 

 360 



1,114 

 312 



209 



107 



108 



205 



113 



21 



64 



2,714 



15.0 



Do 



...do 



13.9 



Do 



...do 



13.1 



Do 



...do 



13.3 



Do 



...do ... 



14.4 



Second generation. 

 Offspring single 



pair. 

 Second generation. 

 Third generation . . 

 Fourth generation. 

 Fifth generation. . . 

 Sixth generation.. . 

 Do 



...do.... 

 ...do.... 



...do.... 



do 



...do.... 

 ...do.... 



...do 



...do. . 



13.4 

 13.5 



16.0 

 13.3 

 13.5 

 15.7 



is. s 

 21.0 



Seventh generation 

 Miscellaneous series 



...do 



...do 



...do.... 



Oct. 11-M 



July 3-Aug. 2... 



May-Oct 



2 



118 



43 

 1,544 



21.5 

 13.1 



21.3 

 13.0 



True grandis. 



539 



7,928 



14.7 



488 



7,086 



14.5 



1,027 



15,014 



14.6 



