12 



CIRCULAR 269, U. S. DEPT. OF AGRICULTURE 



Table 4. — Record of deposition of eggs on flue-cured tobacco in the laboratory by 

 -females of Ephestia elutella at Richmond, Va., 1931 





Date 

 female 

 emerged 







Eggs laid days aftei 



emergence ' 









Total 



num- 



Female Xo. 



i 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



ber of 



eggs 



laid 



1 . . 



July 28 



Julv 31 



do 



6 

 81 



2 

 62 



8 







61 

 28 

 62 

 25 

 43 

 22 

 81 

 77 

 36 

 49 

 90 

 71 

 14 

 52 

 



27 

 13 

 32 

 10 

 8 



25 

 43 

 42 

 59 

 35 

 46 

 42 

 51 

 21 



n 



10 

 4 

 12 

 4 

 6 

 21 

 20 

 18 

 27 

 11 

 7 

 21 

 24 

 20 

 25 

 63 

 24 

 76 



5 

 

 

 3 



37 

 8 

 4 



11 



13 

 

 1 

 



16 

 8 



11 



19 

 9 



29 

 3 



13 

 3 



21 



11 

 7 



41 

 2 

 



16 

 5 



17 



23 



16 



12 



15 



8 











183 



2. 







126 



3 - 



















108 



4 . . 



Aug. 2 

 __.do 





 9 

 

 2 

 

 

 

 

 

 6 

 

 1 



14 

 8 



12 

 5 

 

 1 



13 

 6 



11 



20 

 2 

 

 7 

 



22 







6 















104 



5 _ -- 





















117 



6 - 



Aug. 4 









76 





Aug. 5 i 

 Aug. 6 , 

 Aug. 7 J 

 Aug. 8 



20 

 

 2 

 



14 



14 



7 



6 











211 



8 



148 



9 



1 

 





 

















138 



10 









95 



11 



__do 





 

 1 

 

 

 

 

 



14 

 

 4 

 



51 

 

 



11 



11 







1 



31 









144 



12 



Aug. 9 

 Aug. 10 

 Aug. 11 

 Aug. 12 

 do.— 

















134 



13 - --- -- - 



7 



1 















120 



14 .. - 











101 



15 

















37 



16 - . - 



4 



53 



6 



6 

 9 

 2 

 

 

 5 

 4 

 



14 

 1 

 



21 

 3 



25 







1 



6 

 2 



1 













113 



17 _ . 



Aug. 13 

 Aug. 14 

 - do . 



103 



18 





 52 



1 

 57 

 38 

 17 

 48 

 80 

 47 

 51 

 37 

 40 

 45 



18 











144 



19 



32 15 







1 





 4 

 

 4 

 2 

 













 









123 



20 _..-_- ._ 



Aug. 16 

 Aug. 19 

 _ do. 



48 

 18 

 1 

 14 

 11 

 51 

 37 

 31 

 64 

 13 

 30 



21 

 

 5 



23 

 18 

 42 

 9 

 5 

 39 

 25 

 28 









84 



21 









83 



22 



6 















93 



23 



Aug. 20 



Aug. 21 



Aug. 24 



do. 











126 



24 











99 



25 



26 



13 

 



9 

 



2 



4 



1 



279 

 109 



27 



Aug. 29 

 Aug. 30 

 Sept. 4 

 Sept. 5 









98 



28_ 



14 

 

 8 



17 



12 











227 



29 







87 



30 



4 















210 











Total 



*>83 



1,224 



S79 



623 



313 



162 



147 



62 



77 



37 



R 



4 



1 



3,820 















1 The egg-laying records extend from the day of emergence to the day of death of the female. 



DISCUSSION 

 SEX RATIOS 



The egg-to-adult rearings shown in Tables 1 and 2 were composed 

 of 60 moths, 46.7 per cent males and 53.3 per cent females. The sex 

 of 473 additional moths collected in infested tobacco warehouses was 

 determined; of these, 60 per cent were males and 40 per cent females. 



NATURAL ENEMIES FOUND ATTACKING EPHESTIA ELUTELLA 



During the summer of 1930 a wasplike insect was observed parasit- 

 izing the larvae of Ephestia elutella. Specimens were identified by 

 A. B. Gahan, of the Bureau of Entomology, as Microbracon hebetor 

 (Say). During October and November, 30 egg-to-adult rearings of 

 this parasite were completed in the laboratory, well-grown larvae of 

 E. elutella being used as food. The developmental periods were as 

 follows: Incubation period, 2 to 3 days; larval period, 8 to 10 days; 

 pupal period, 9 to 12 days; and egg-to-adult period, 20 to 24 days. 

 These records were obtained when the temperature ranged from 73° 

 to 78° F. The effectiveness of this parasite in reducing the numbers 

 of E. elutella larvae in tobacco warehouses has not been determined. 



A small mite was collected in tobacco warehouses during the sum- 

 mer of 1930 from the bodies of adults of E. elutella. Specimens were 

 identified by H. E. Ewing, of the Bureau of Entomology, as a species 

 of Seius. 



