BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. H 



LOCATIONS SELECTED FOR OVIPOSITION ON SEA-ISLAND AND 

 UPLAND COTTON SQUARES. 



Upland cotton squares are usually punctured at the base of the 

 square, as is shown in Plate I, figure 2. During the writer's studies 

 at Thomasville, Ga., in 1916, the majority of the punctures were 

 observed, in the case of sea-island cotton, to be on the upper portion 

 of the square. There is little proliferation around the weevil punc- 

 tures on the sea-island squares, the punctures being mere specks as 

 compared to those on upland cotton. This characteristic location for 

 egg deposition is shown in Plate I, figure 1. 



PERIOD FROM EMERGENCE TO OVIPOSITION. 



Female weevils bred in the outdoor insectary required an average 

 period of 8.9 days from the time they became adult to the date of 

 oviposition. The period of time from emergence to oviposition 

 varied from 6 to 20 days for weevils bred under insectary condi- 

 tions. 



Boll weevils bred under normal field conditions appeared to have 

 more vitality than weevils bred under insectary conditions. A 

 record of 38 first-generation weevils bred under normal field condi- 

 tions gave an average period of 7.07 days from the time they became 

 adult to the date of oviposition. 



OVIPOSITION PERIOD OF THE BOLL WEEVIL UNDER INSECTARY 



CONDITIONS. 



The oviposition records for the weevil on upland cotton are pre- 

 sented in Table V. Hibernated female weevils kept with male 

 weevils throughout life deposited eggs over an average period of 

 35.9 days compared with an average period of 21.7 days for females 

 that were not kept with male weevils. The hibernated fertilized 

 and nonfertilized weevils deposited a total of 3,605 eggs or an average 

 of 7.2 eggs per day per female. During the lifetime of both series 

 of hibernated weevils an average of 171 eggs was deposited by each 

 female. The greatest number of eggs deposited during any one day 

 by a single hibernated female weevil, under insectary conditions, was 

 20. The heaviest oviposition during the lifetime of both series of 

 weevils was from the fifth to twenty-fifth days (fig. 4). The first- 

 generation weevils deposited eggs for a period of 39.7 days and the 

 second generation over a period of 35.2 days. The average period 

 of oviposition on upland cotton for all weevils under observation was 

 33.1 days. The relationship between the mean daily temperature and 

 the mean daily oviposition of the hibernated weevils is shown to cor- 



