February, '17] BECKER: PEACH-TREE BORER 55 



On the basis of 29 moths the 1913 crest of emergence was September 

 7, and in 1914, on a basis of 94, it was August 31. It is not impossible 

 that the change in elevation and, to a lesser extent, latitude, may have 

 influenced the Abbott and El Dorado emergence records. 



Getting our records as we did, however, it would appear that emerg- 

 ence at El Dorado is ten days earlier than at Fayetteville, while at 

 Abbott in 1913 emergence was actually ten days later than the Fayette- 

 ville average (September 4) and in 1914, four days earlier. 



In connection with the 1913 Abbott data it might be well to note 

 that it was made on a basis of only 29 moths and could hardly be con- 

 sidered as representative. The 1914 data was on a basis of 94 moths 

 and is considered more representative. As further evidence of the 

 difference between these different points I find in my notes of August 

 16 and 18, 1913, made at El Dorado and Abbott, respectively, this 

 note: "From the general condition of the pupae and the proportion 

 of larvae to pupae, indications are that Abbott is about one week be- 

 hind El Dorado on emergence." The 1914 data would bear this out. 

 Following is a table of comparison of the crests of emergences. 



Location 1910 1912 1913 1914 1915 1916 



Fayetteville Sept. 8 Sept. 2 Aug. 29 Sept. 5 



Abbott Sept. 7 Aug. 31 



El Dorado Aug. 24 Aug. 26 Aug. 22 



It would seem that we are warranted in concluding from the data 

 that the emergence at El Dorado, a point nearly 3° south of Fayette- 

 ville and with a difference in elevation of about 1200 to 1300 feet in 

 favor of Fayetteville, that emergence is certainly one week earlier and 

 probably ten days, while at Abbott, a point 1° south with a difference 

 of 864 feet elevation in favor of Fayetteville, there is enough to sug- 

 gest that emergence is four days ahead of Fayetteville. 



Annual Variation in Abundance 



Although it would appear that the peach tree borer would not be as 

 subject to temperature, humidity and other weather changes as an 

 insect living out in the open, the emergence records of 1910, 1912 and 

 1913 made from the same trees, show an interesting variation in the 

 number of insects which bred to maturity in these years. 



It w^oulcl seem that this variation would have its explanation to 

 some extent, at least, in a careful study of climatological variations. 

 In this instance the fluctuation maj'" be due to changes on the condi- 

 tion of the trees, rather than on the insect. In 1910 there were 350 

 insects to breed to maturity in the orchard which was studied. In 

 1912, 287 bred to maturity and in 1913 there were 405 to breed to 

 maturity. 



