October, '11] 



CUSHMAN: BIOLOGY OF BOLL WEEVIL 



44o 



were added and the average struck. These average temperatures, 

 together with the average developmental periods of the weevils reared 

 during the different periods, and the number of weevils representing 

 each period, are shown in Ta))le IX. The relation between the tem- 

 perature and the developmental period is shown in graphic form on 

 the chart. This chart shows that the relation l)etween the average 

 periods and any of the temperature curves is most intimate with that 

 of the minimum, the developmental curve going down as a rule when 

 the minimum curve goes higher. The only exceptions to this rule are 

 found in the first and fifth periods. These two periods were repre- 



i»*»S» 



Chart fallowing relation between temperature and developmental period of cotton 



boll weevil 



