45 



the maintenance of favorable conditions for the weevil, was made up 

 as follows: A 4 or 5-inch shallow earthen saucer, such as is used with 

 flowerpots, was filled with soil, which was kept fairly moist. Over 

 this was placed a fresh cotton leaf, which conserved the moisture from 

 the soil, but never became wet, and kept both weevils and squares 

 clean, besides facilitating the handling necessary to frequent renew- 

 als of the food suppl}^ and the consequent transference of the weevils. 

 The rest of the cage was formed by an ordinary lantern globe covered 

 at the top by cheese cloth held firmly in place by a rubber band. With 

 this apparatus weevils could be readily observed without disturbing 

 them, and food supplied was kept in good condition and could be 

 easily renewed, while there were no cracks to hide in or to allow 

 weevils to escape (PI. V, fig. 22). The moisture of the soil and fresh 

 leaf covers were renewed as needed. Clean squares were supplied 

 each day, and the actual number of egg and feeding punctures recorded 

 upon numbered slips kept with each cage. The sex of each weevil 

 was also determined and noted upon its death, thus giving an accurate 

 record of the number and sex of weevils responsible for the punctures 

 recorded. Most of the weevils used were bred, so that the exact 

 period of their lives is known. Duration of life refers onl}^ to adult 

 life from the time of emergence from the square or boll to the death 

 of the weevil. Many weevils brought in from the field were under 

 observation in the laboratory for periods sufficientl}^ long to justify 

 the inclusion of the results obtained from them with those of weevils 

 which were bred. Obviousl}^ the time these were under observation 

 does not represent their true length of life; therefore the inclusion of 

 both results renders the averages obtained the more conservative. 



Table YK..— Duration of life of v)eevils upon squares. 





Males. 



Females. 





Number. 



Average 

 days. 



Number. 



Average 

 days. 



Weevils placed in hibernation Dec. 15, 1902; living Apr. 15, 

 1903 



23 

 66 



180 

 223 



14 

 53 



171 



Hibernated weevils taken spring, 1903; estimated adult Dec. 

 15, 1902 



220 







Hibernated weevils, from time of feeding in 1P03 



f 23 



1 67 



30 



18 



9 



57 

 88 

 58 

 43 

 76 



16 

 52 

 25 

 10 

 9 



37 



Fiist generation, bred 



80 



56 



Third generation, bred 



54 



Fifth generation, bred 



54 







Totals and weighted averages, including hibernation period. 

 Totals and weighted averages, not including hibernation 

 period 



146 



147 

 89 



151 



71 

 212 



111 



112 



67 



148 

 64 



Entire duration of life, hibernated weevils only 



210 







Whether we include the time of hibernation or not, it appears from 

 the averages of 156 hibernated weevils that those which winter suc- 

 cessfully are longer lived than any following generation, as their active 

 life in spring averaged fully 80 days for males and TO for females. 



