18 



BULLETIN 189, U. S. DEPARTMENT OF AGEICULTURE, 



INVESTIGATIONS IN 1913. 

 SPRING-BROOD MOTHS. 



Table XII gives the emergence of moths of the spring brood at 

 Hagerstown in 1913. 



Table XII. — Emergence of spring-brood moths of the codling moth at 

 Hagerstown, Md., in 1913. (See fig. 10.) 



Date of obser- 

 vation. 



Number 

 of moths 

 emerging. 



Date of obser- 

 vation. 



Number 

 of moths 

 emerging. 



May 1.5 



2 

 6 

 12 

 9 

 38 

 77 

 87 





45 

 22 

 25 

 81 



18 



8 



21 



11... 



24 



27 



27.. 



Total 



30 



404 



June 2 





The first moths appeared in the rearing cages on May 15, but 

 maximum emergence did not occur until May 30 to June 2. Careful 



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Fig. 10. — Diagram to illustrate emergence of spring-brood and first-brood moths of the codling moth at 



Hagerstown, Md., in 1913. 



records were taken every three days up to and including June 11, 

 but from June 11 to June 27 observations were discontinued, as indi- 

 cated by the dotted line in figure 10. However, of 404 moths 

 accounted for in Table XII, all but 81 had emerged by June 11, 

 and the break from then until June 27 does not seriously affect the 

 value of the records. Allowing 10 to 12 days for egg laying and 

 incubation, first-brood larvae were evidently beginning to feed by 

 May 25 to 27. 



FIRST-BROOD MOTHS. 



The relation of the two broods of moths emerging at Hagerstown 

 in 1913 is clearly illustrated in figure 10. Adults appeared in the 

 rearing jars with more or less regularity from July 8 to August 10. 

 Emei-gence ceased altogether on August 28. (See also Table XIII.) 



