86 



BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



Moths of the spring brood, 1916. — Observations of the time of 

 emergence of moths of the spring brood were made hourly from 

 7 a. m. to 6 p. m. from May 17 to 31, inclusive, as recorded in Table 

 LXII. It will be noted therein that the largest number of moths 

 issued between 12 o'clock noon and 1 p. m. The heaviest emergence 

 period was the five-hour interval from 9 a. m. to 2 p. m., during 

 which 895 moths, or 67.14 per cent of the total number of 1,333 moths, 

 issued. Only 40 moths, or 3 per cent of the total, emerged during 

 the period of 13 hours from 6 p. m. until 7 a. m. 



Table LXII. — Emergence of codling moths of the spring brood, hourly, from 

 7 a. m. to 6 p. m., Grand Junction, Colo., 1916. 



Date of 

 emergenc 

 of moths. 



Ob- 

 serva- 

 tion 

 No. 



Number of moths emerging at— 



Total 

 num- 

 ber 

 of 

 moths. 







A 



.M. 





P.M. 



7 



8 



9 



10 



11 



12 



1 



2 



3 



4 



5 



6 



May 17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 

 25 

 26 

 27 

 28 

 29 

 30 

 31 



Total 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 

 14 

 15 













10 

 19 



27 



34 

 9 

 15 



5 

 4 



18 



2 

 6 

 5 



2 







53 



70 



131 







11 



157 



149 



245 



62 



40 



50 



1C9 



91 



110 



55 



1 







1 



27 



30 



27 







4 



4 



3 





1 





















7 

 2 

 5 



10 

 1 

 2 

 3 

 3 

 5 

 4 

 1 



48 



2 

 5 

 2 

 7 

 1 



2 

 1 



"h' 

 l 





1 





7 



21 

 29 

 25 



40 

 50 



8 



49 

 32 

 13 

 17 

 15 

 24 

 18 

 19 

 13 

 8 



19 



17 

 15 

 25 

 20 

 11 

 7 



19 

 5 

 8 



12 



14 

 6 



15 

 3 

 8 

 6 



10 

 3 

 2 



92 



'37 

 1 



29 

 1 



55 



34 





















3 

 24 

 15 

 14 



8 



1 



1 













50 

 21 

 23 

 12 









2 

 40 

 12 



1 





2 



5 

 3 



.... 



40 



35 



61 



123 



238 



218 



266 



173 



27 



12 



1.333 





' About 5 of these moths found at 7 a. m. were spreading their wings, having 

 emerged between 6 and 7 a. m. 



Moths of tJie first brood, 1916. — A study of the time of emergence 

 of first-brood moths was begun July 17 and ended August 4, and 

 during this time observations were taken hourly from 6 a. m. to 

 G p. m. The record of the observations shows that a total of 1,761 

 moths emerged, as is given in Table LXIII. The maximum emer- 

 gence for a 1-hour period was 213 moths, which issued from 9 to 10 

 u. m. During the 5-hour period from 9 a. m. to 2 p. m. 923 issued, 

 or 52.41 per cent of the total number of moths emerging. For the 

 13-hour period from 6 p. m. to 7 a. m. 61 moths, or 3.46 per cent, 

 emerged. 



From the foregoing studies it will be noted that the majority of 

 the moths of the spring and first broods emerged during the latter 

 part of the morning and early part of the afternoon, with the maxi- 

 mum emergence usually occurring from 9 to 11 a. m. During the 

 5-hour period from 9 a. m. to 2 p. m. from 52 to 67 per cent of the 

 moths emerged; whereas during the 13-hour interval from 6 p. m. 

 to 7 a. m. only from 3 to 5 per cent issued. 



