LONGEVITY OF WEEVILS AFTER EMEEGENCE. 87 



Only about two-thirds as many weevils were carried through in 

 the fed tests as in the unfed tests. Among the total of 2,965 weevils 

 55 per cent were males, while in the unfed experiments 57 per cent 

 were males. The average duration of life shows but very slight 

 variation between the sexes, both living between twenty-five and 

 twenty-six days. This average is somewhat smaller than has pre- 

 viously been obtained in similar experiments, and this is probably 

 due to the greater exposure to sunshine of the cages in wdiich the wee- 

 vils were kept in this series of experiments. The average period of 

 life mth food was about two and one-half times that without food. 



Among the fed weevils, as among the unfed, the longest life occurred 

 at Dallas. This also was a male weevil which emerged from hiberna- 

 tion on May 6 and survived until September 13, or one hundred and 

 thirty days. The greatest length of life for a female occurred at Cal- 

 vert. This weevil emerged on April 11 and died on August 7, having 

 been active one hundred and eighteen days. 



The full length of life of the last weevil dying in these experiments 

 is also a matter of interest. This weevil was collected in the field at 

 Dallas and placed in the hibernation cage on October 16, 1906. 

 From that time until May 6, 1907, it had no food. The period from 

 its collection until its death lacked but a day or two of being eleven 

 months, during three-fifths of which period it existed without food. 

 This is next to the longest lived boll weevil of which we have record, 

 the longer record being slightly more than eleven months in the case 

 of a male weevil hibernated at Victoria in 1903. 



In a study of the emergence movement and of the duration of life 

 of fed weevils by ten-da}" periods we have used the total number of 

 weevils of each sex observed in each locahty as the basis upon w^liich we 

 have determined the percentage of mortality occurring in each succes- 

 sive ten-day period. The full records for each locahty have been 

 omitted and only the totals for each sex in each locality have been 

 included in Table XLV (p. 88). The emergence from hibernation was 

 distributed through four months, or slightly more, in 1907. A study 

 of the omitted records shows that, as a rule, the weevils living longest 

 emerged at approximately the middle of the emergence movement. 

 It is probable that these weevils were among those which entered 

 hibernation at the most favorable period during the preceding fall 

 and that they found also the most favorable class of shelter conditions 

 to protect them during the winter. The importance of brealdng up 

 tliis succession of conditions, so favorable to the survival of wee\als, 

 their maximum length of life, and, consequently, their greatest inju- 

 riousness, need only be mentioned to be appreciated. That early 

 fall destruction of stalks, the cleaning up of rubbish which might 

 shelter weevils most favorably during the winter, and the early 

 planting and uniform planting of the crop are all logical parts or steps 



