February, '17] BECKER: PEACH-TREE BORER 59 



shaded so that they will not get all of the morning or all of the afternoon 

 sun the period of incubation may be two weeks. 



It will be seen from the figures given in this paper that an average 

 female may be expected to deposit 800 eggs, 97 per cent, of which 

 may be expected to be fertile and 84 per cent, of which are effectively 

 placed. This would mean that there would be an average of 650 

 larvae from each female which have a chance to mature. If the in- 

 festation of an orchard remained steady from year to year it would 

 mean that 648 of these would fail to reach maturity. In other words, 

 only one out of every 325 would reach maturity. This would mean 

 a mortality of 99.69 per cent., or, made on a basis of all larvas which 

 hatched, there would be a mortality of 99.74 per cent. 



With 650 larvae to attempt to take the place of every pair of moths 

 which bred to maturity, it is not difficult to see why tree protectors 

 have failed to give the desired protection against the pest. If we 

 were to take these figures we would find that a tree protector, in order 

 to be 50 per cent, efficient, would have to keep out 649 out of every 650 

 borers which are trying to find a place to enter the tree and if the 

 protector were 90 per cent, efficient the protector would have to 

 exclude 3,249 out of every 3,250 borers. Although 3,240 out of the 

 3,250 would fail to breed to maturity under normal conditions, en- 

 tomologists must realize what they are trying to do when they attempt 

 to keep out the additional nine of this tremendous number of borers 

 which are attempting to run the gauntlet of even a 90 per cent, efficient 

 tree protector. 



Vice-President G. A. Dean: Is there any discussion? 



Mr. F. L. Washburn: It would be interesting to hear the method 

 of taking the pictures showing the various stages of the insect. 



Mr. G. G. Becker: The pictures were taken with arc light rays. 

 Pupae that were about ready to emerge, as indicated by a little rift 

 which appeared across the top, were brought into the laboratory and 

 then subjected to the rays of the arc light. Adjustments had pre- 

 viously been made so that on being subjected, they could be snapped 

 at whatever stage was desired. 



Vice-President G. A. Dean: Mr. Hugh Glasgow will present 

 the next paper. 



THE SINUATE PEAR BORER IN NEW YORK 



By Hugh Glasgow, Agric. Expt. Stat., Geneva, N. Y. 



(Withdrawn for publication elsewhere) 



