COTTON BOLL WEEVIL IX THE MISSISSIPPI VALLEY. 13 



direct influence on the length of time elapsing between emergence 

 and oviposition. Ten typical thurberiae emerging in late July and 

 early August averaged 6.8 days from emergence to oviposition. These 

 periods ranged from 3 to 10 days. Grandis females in Texas in 1913 

 averaged 6.1 days and thurberiae females 4 days. At Tallulah in 

 1910, 34 females averaged 6.35 days before oviposition. 



PERIOD FROM FIRST FEEDING ON SQUARES TO OVIPOSITION. 



The period from first feeding on squares after emergence from 

 hibernation to egg deposition was observed only with typical thur- 

 beriae females and with crosses of grandis and thurberiae. With 

 typical thurberiae emerging in June it ranged from 10 to 18 days with 

 an average of 13.3 days, while male thurberiae mated with female 

 grandis varied from 3 to 10 days with an average of 7 days. With 

 female thurberiae mated with male grandis the period varied from 9 

 to 18 days with an average of 12 days. Female thurberiae mated 

 with male grandis in Texas in 1913 averaged 13.5 days in May and 

 June and 3 days in early September, while hibernated grandis 

 males averaged 4.2 days in early May. These records seem to indi- 

 cate that the period is several days longer for thurberiae than for 

 grandis. 



FECUNDITY. 



In connection with the various breeding series conducted during 

 1915 a considerable amount of information on the fecundity of the 

 females of various types was secured. 



Fecundity of hibernated grandis females. — Questions have fre- 

 quently been raised concerning whether or not it is necessary for a 

 female to be fertilized in the fall to pass the winter safely and also as 

 to whether or not it is necessary for the females to be fertilized in the 

 spring before deposition can start. Two series of females were 

 tested to determine their exact condition upon emergence from 

 hibernation in the spring. One series consisted of isolated females 

 which were collected immediately after emergence started and which 

 were not offered an opportunity for copulation after that time, while 

 in the other series males were left with the females throughout their 

 life. Of course there is a possibility that some of these females may 

 have been fertilized during the time between emergence and collec- 

 tion but this is very slight as the emergence had just started and they 

 had had very little time in which to copulate. Earlier studies have 

 shown that either square or boll food is necessary before the female 

 can be successfully fertilized and there were extremely few squares 

 present in the field before the time of collection of these weevils, 

 consequently it seems safe to assume that at least the majority of 

 these females had not been fertilized in the spring. Both series were 

 given cotton squares for food and oviposition. 



