HIBERNATION AND DEVELOPMENT OF BOLL WEEVIL. H 



pupae and adults in the presence of eggs and larvae is that an outbreak 

 of the cotton leaf -worm {Alabama arglllacea Hbn.) had completeh^ 

 defoliated the plants during the latter part of September, preventing 

 entirely the formation of squares, and thus stopping abruptly for a 

 short time the multiplication of the weevils in squares. Subsequentl}^ 

 squares were formed, and when these became large enough the repro- 

 duction of weevils was resumed after about November 1, so that most 

 of the larvae found were over half grown. In lots 4 and 5, when exam- 

 ined November 20 and 22, from 10 to 12 per cent of the eggs were still 

 unhatched. It seems probable that at this time some of the eggs, but 

 no large percentage, failed to hatch. Most of the larvae died during 

 the first stage and but few lived to be over half grown. On Novem- 

 ber 12, in lot 2, 25 eggs were found in 98 squares, which were col- 

 lected November 7, showing that the Qgg period had been doubled. 

 Mr. Conradi notes in this connection that the life-history period was 

 first noticed to be decidedly lengthened after November 9, eggs laid 

 November 10 requiring 5 da^^s to hatch. From 24 eggs hatched 

 between November 24 and 28, 15 larvae died within a day after hatch- 

 ing, T by the time the}^ were half grown, and but 2 developed into 

 weevils, which emerged December 4. 



On December 12 an occasional larva was found in the field and sev- 

 eral were brought into the laboratory, where 3 transformed to pupae 

 January T, but then died. They would undoubtedly have failed to 

 pupate in the field. 



MORTALITY OF HIBERNATING WEEVILS. 



The mortality of weevils during hibernation is shown in Tables I and 

 III. Table I gives the mortality of weevils confined in cages at dif- 

 ferent dates from October 7 to November 17, as previously described. 

 In bat two lots did weevils survive the winter. In these lots (5 and 7), 

 of 500 weevils an average of 6.2 per cent survived the winter and were 

 active between March 22 and March 24. On March 21, however, 10.5 

 per cent were alive, and it was noted that these weevils had been active 

 since March 18, so that practically 7.5 per cent of the two lots survived 

 the winter under the supposedly favorable conditions furnished them 

 in the hibernation cages. 



9223— No. 63, pt 1—07 3 



