113 



conclusion seems plain that so long as leaves alone are fed upon, 

 eggs do not develop, while a diet of squares leads to the development 

 of eggs in about 4 days. It is worthy of note that the interval 

 between the first feeding upon squares and the deposition of the first 

 eggs is almost the same with these weevils taken in middle life as 

 with weevils which have just emerged. 



An examination of hibernated females taken in the spring of 1903, 

 which had fed for 6 weeks upon cotton leaves, showed that their 

 ovaries were still latent. Copulation was rarely observed among 

 hibernated weevils until after squares had been given them. In a few 

 da3^s after feeding upon squares, mating and oviposition began. The 

 average period was from 3 to 5 days, and, having once begun, ovipo- 

 sition continued regularly. 



It has been found that food passes the alimentary canal in less than 

 24 hours. Assimilation, therefore, must be very rapid. It is evident 

 that while leaves will sustain life certain nutritive elements found 

 only in squares are essential in the production of eggs. 



These experiments were repeated in 1904 with similar results. 



Upon dissecting weevils just taken from hibernation, it was found 

 that females contained no developed eggs, but that their ovaries were 

 in an inactive condition, similar to those of females which had fed for 

 months entirely upon leaves during the previous fall. Upon examin- 

 ing females taken from seppa cotton later in the spring, but before 

 squares had appeared, it was found that they also were in similar 

 condition. This was also true of females kept in the laboratory from 

 the time of emergence from hibernation until squares became abun- 

 dant with only leaves for food. It seems peculiar that upon a purely 

 leaf diet eggs are not developed, but all observations made indicate 

 that this is the case. It can not be said definitely whether the females 

 examined had been fertilized, but it is certain that they were not 

 ready to deposit eggs. 



PROGRESS OF INFESTATION IN FIELDS. 



From among the many notes made upon this point the results of 

 the study of two fields are here presented. The first field, consisting 

 of about 15 acres, had been planted in cotton for several years and 

 was closel}^ surrounded by other cotton fields. The second field of 

 35 acres was upon newly broken land and situated in a comparatively 

 isolated location. 



Examinations were made frequently to determine approximatel}^ the 

 percentage of infested squares present in various parts of these fields. 

 The conditions of the examinations were made as uniform as was 

 possible. The fields were divided into blocks, and practically the 

 same ground was covered in each block upon succeeding examinations, 



16780— No. 51—05 8 



