BULLETIN 



U. S. DEPARTMENT OF AGRICULTURE. 



Records obtained from a large number of females, collected in the 

 fields and placed in separate cages for egg deposition, show the average 

 number of eggs laid to be 177. Among the records obtained at Appo- 

 mattox, Va., during 1910, are those in Table II. 



Table II. — Number of eggs laid by the tobacco Crambus, Appomattox, Va., 1910. 



No. 

 of fe- 

 male. 



Moth collected. 



Period of OA T ipo- 

 sition. 



Num- 

 ber 

 eggs 

 laid. 



No. 



offe- i Moth collected, 

 male, j 



Period of ovipo- 

 sition. 



XT 



Num- 

 ber 

 eggs 

 laid. 



1 



1910. 



July 8 



do 



.do 



1910. 

 July 9-13 



218 

 68 



271 

 156 

 211 

 316 

 287 

 77 

 301 



10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 



1910. 

 Aug. 11 



1910. 



Aug. 12-15 



Aug. 12-16 



Aug. 15-20 



Aug. 15-18 



Aug. 16-20 



Aug. 16-19 



Aug. 16-21 



Aug. 16-18 



83 



2 

 3 



do 



July 9-14 



do 



Aug. 14 



203 

 218 



4 



July 10 



July 12 



July 17 



do 



Julv 25 



July 11-14 



do 



194 





Julv 13-18 - . 





222 



6 



Julv 18-22 



do. . 



91 





July 18-23 



do 



238 



8 



Julv 26-30 



do 



63 



9 



Aug. 11 Aug. 12-16 







Several individual females laid over 300 eggs, and over 300 were 

 obtained in several instances by dissection. It is probable that the 

 average number of eggs deposited normally is above rather than 

 below the average obtained in the cages, as some of the moths may 

 have laid eggs before capture, although records were not included 

 from moths which deposited eggs within 12 hours after capture. 1 



The period of opposition lasts from 3 to 5 days, the females djrng 

 shortly after egg laying is finished. The records of two females col- 

 lected in the field on August 10, 1910, are given in Table III. 



Table III. — Rate of oviposition of the tobacco Crambus, Appomattox, Va., 1910. 



Female No. 1. 



Date. 



Num- 

 ber of 

 eggs de- 

 posited 



1910. 



Aug. 11 1 7 



Aug. 12 ! 89 



Aug. 13 70 



Aug. 14 36 



Aug. 15 19 



Total i 221 



Female No. 2. 



DURATION OF THE EGG STAGE. 



The period of incubation was found to be from 5 to 9 days, the 

 greater number of eggs hatching about the sixth day at ordinary 

 summer temperatures. 



1 The dissection of 17 females of Crambus caliginosellus collected in the field during the third week in 

 July, 1912, showed that 8 of the 17 collected contained more than 100 eggs. The number of eggs (mature 

 or nearly mature) found in the 8 moths containing more than 100 eggs was as follows: 143, 322, 127, 290, 

 307, 124,342,208. 



