98 



would be limited to about 250,000 weevils per acre. The possibility 

 that the progeny of one weevil will amount to 12,000,000 in the course 

 of a season would therefore rarely if ever be realized. 



THEBMAIi INFLUENCE UPON ACTIVITY AND DEVELOPMENT. 



The influence of temperature has been frequently mentioned as an 

 important point, but it may be more clearly understood by collecting 

 some of the most important observations relating to it. A study of 

 this subject throws much light upon such questions as seasonal and 

 daily activity, the rapidity of development at various seasons, hiber- 

 nation, and the time of emergence from hibernation. The influence 

 upon development will be first considered. For a portion of these 

 observations an ice box was especially designed and constructed to 

 facilitate observations at low and constant temperatures. (See 

 PL XVI, fig. TO.) 



Table XXIII. — Thermal wfluence on development. 



Stage. 



Egg 



Larva 



Pupa 



Nnmber 

 of obser- 

 vations. 



Entire develop- 

 mental period. 



385 

 107 



195 

 15 

 15 



88 



161 



81 



167 



29 



4 



88 



96 



305 



66 



100 



185 

 135 



Period, 



1902. 



Sept. 4 to Oct. 8 , 



Oct. 7 to Nov, 13 , 



Nov. 24 to Dec. 15 



Ice-box experiments, 1904 



Sept. 6 to Oct. 5 



Sept. 26 to Oct. 21 



Nov. 11 to Dec. 12 



Ice-box experiments, 1904 



Julv6to31 



Sept. 15 to Oct. 3 



Sept. 24 to Oct. 28 



Nov.2tol3 



Dec. 2 to 29 



Ice-box experiments, 1904 



Ang. 10 to Sept. 80 



Sept 16 to Oct. 15 



Oct. 8 to Nov. 16 



1903. 



June 4 to July 15 



Aug. 2a to Sept. 28 



In ice box, 1904 



Average 

 time for 

 stage. 



Days. 



3- 



4+ 



II. 



5.1 



7.5 



9.5 



25.0 



12.5 



3.5 



5.2 



6.0 



7.6 



14.5 



7.5 



13. 4 

 17.5 

 20.3 



18.3 

 19.0 

 30.0 



Effective tempera- 

 ture. 



Average. 



38.0 

 30.0 

 19.0 

 27.0 



3.5.7 

 30.6 

 19.5 

 27.0 



89.65 

 36.0 

 31.1 

 26.2 



32.0 

 33.1 



23.0 



Total. 



°F. 

 114.0 

 120.0 

 209.0 

 137.7 



26-7.7 

 280. 7 

 487. 5 

 837.5 



138.8 

 187.2 

 186.6 

 199.1 

 268.2 

 202.5 



54^.4 

 588.0 

 598.8 



585.6 

 628.9 

 690.0 



SUMMARY OF THE PRECEDING TABLE. 



Stage. 



Total 

 observa- 

 tions. 



Average 

 period 



for 

 stage. 



Average 

 effective 

 tempera- 

 ture. 



Total 

 effective 

 tempera- 

 ture. 



Egg 



Larva 



Pupa 



Total development, sum of stages 

 Observations on entire period 



616 

 313 

 530 



Days. 

 4.0 

 9.8 

 5.5 



F. 



34.0 

 32.2 

 83.2 



1,459 



887 



19.3 

 19.6 



32.9 

 32. 2 



F. 



136.0 

 315.6 

 182. 6 



634.2 

 632.0 



