COTTON BOLL WEEVIL IN THE MISSISSIPPI VALLEY. 7 



Table III. — Comparative longevity of Anthonomus grandis and A. g. thurberiae. 



Food. 



Average 

 longevity 

 of grandis. 



Average 

 longevity 

 of thur- 

 beriae. 



Okra fruit 



Cotton leaves 



Cotton bolls 



Cotton squares 



Average longevity irrespective of food 



5.4 

 8.17 

 31.41 

 54.56 



Days 



18.3 

 62.04 

 48.6 

 61.4 



14.13 



53.2 



The longevity of thurberiae is greater in every instance than that of 

 grandis, and the average longevity irrespective of food is nearly forty 

 days greater for the thurberiae weevils. 



The maximum longevity obtained in the 1915 experiments is 104 

 days, this record being made by a male tliurberiae feeding on cotton 

 squares. 



The maximum longevity with no food was 40 days; on okra and 

 Hibiscus 39 days; on cotton leaves 97 days; on cotton bolls 82 days; 

 on cotton terminals 45 days, and on cotton squares 104 days. 



The comparison of the longevity by sexes is shown in Table IV. 

 Here it is seen that in grandis the females exceeded the males on every 

 food except cotton squares while in the thurberiae variety the males 

 lived the longer in each case. The observations relating to grandis 

 are in accord with the earlier records, which stated that the females 

 exhibited greater hardihood on abnormal foods, but that the relation 

 was reversed with normal food. 



Table IV. — Comparison of longevity of the boll weevil by sexes. Observations of 1915. 



VARIETY GRANDIS. 





Males. 



Females. 



Food. 



Number. 



Weevil 

 days. 



Longev- 

 ity. 



Number. 



Weevil 

 days. 



Longev- 

 ity. 





136 

 70 



135 

 75 

 17 

 16 



440 

 531 

 1,067 

 1,101 

 345 

 926 



Davs. 

 3.24 

 7.60 

 7.90 

 14. 68 

 20.30 

 57.88 



91 

 69 

 117 

 73 

 17 

 18 



353 

 559 

 992 

 1,255 

 723 

 929 



Days. 

 3.88 





8.10 





8.48 





17.19 



Cotton bolls 



42.53 





51.61 









449 



4,410 



9.82 



385 



4,811 



12.50 







VARIETY THURBERIAE. 



Okra 



8 

 16 

 10 

 22 



163 



997 



531 



1,386 



20.4 

 62.3 

 53.1 

 63.0 



8 

 10 



9 

 29 



129 

 616 

 392 



1.747 



16.1 



Cotton leaves 



61.6 





43.6 



Cotton squares 



60.2 









56 



3,077 



54 9 



56 



2,884 



51 5 







