14 



BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



tire day, with a total of 0.29 inch of precipitation. The development 

 and activity of the codling moth were almost completely arrested, 

 with the result that no moths issued and no eggs were deposited. 

 With normal temperature conditions on May 18, 19, and 20, the 

 emergence of moths would doubtless have been large. The weather 

 turned increasingly warmer May 22, 23, and 24, and on the latter 

 date the maximum number of moths (196) issued. Thereafter the 

 emergence gradually decreased, the rate conforming closely to the 

 variations of the temperature until all of the moths had issued. 



Table V. — Time of emergence of codliiui moths of the spring brood, Grand 



Junction, Colo., 1915. 



Date of 



Num- 



Date of 



Num- 



Date of 



Num- 



Date of 



Num- 



Date of 



Num- 



emer- 



ber of 



emer- 



ber of 



emer- 



ber of 



emer- 



ber of 



emer- 



ber of 



gence. 



moths. 



gence. 



motbs. 



gence. 



moths. 



gence. 



moths. 



gence. 



moths. 



May 12 



8 



May 23 



126 



June 2 



1 



June 12 



8 



June 22 



2 



13 



30 



24 



196 



3 



14 



13 



1 



23 







14 



15 



25 



135 



4 



4 



14 



10 



24 



1 



15 



30 



26 



41 



5 



6 



15 



8 



25 







16 



83 



27 



102 



6 



3 



16 



2 



26 







17 



108 



2S 



95 



7 



15 



17 



2 



27 







18 



24 



29 



74 



8 



32 



18 



4 



28 







19 



26 



30 



65 



9 



33 



19 



6 



29 



1 



20 

 21 





 2 



31 

 June 1 



46 

 56 



10 

 11 



26 



10 



20 

 21 



8 

 







Total... 



1,539 



22 



80 



















Oviposition by moths of the spring brood. — In Table VI are re- 

 corded the observations of the oviposition of 1,140 female moths con- 

 fined with 1,007 male moths in 92 cages. In this connection it is 

 of interest to note the variations in the time of oviposition by the 

 moths in the several cages. Thus, moths emerging May 12 and 

 confined in cage- 1 did not deposit eggs until May 22, whereas the 

 moths in cage 2, although issuing a day later, commenced oviposi- 

 tion May 15. A more detailed study of the table will show numerous 

 variations of the oviposition habits of the moths. A summary of the 

 data is as follows: The number of days before oviposition averaged 

 G.19, the maximum was 19, and the minimum 2 ; the number of days 

 for the period of oviposition averaged 13.82, maximum 33, mini- 

 mum 1 ; the average number of days from the date of emergence to 

 the date of last oviposition was 19.14, maximum 37, minimum 5. 



X umber of eggs per female moth. — It was found in the oviposi- 

 tion studies of the moths of the spring brood that the average num- 

 ber of eggs deposited was 12.59 per female moth. This number was 

 obtained by dividing (lie total number of eggs deposited by the 

 total numberof female moths caged, as shown in Table VI. 



