78 N. H. AGR. EXPERIMENT STATION. [Bulletin 171 



most favorable conditions for these stages; but even here the 

 proportion of mature larvae to egg punctures may be only as 1 

 to 2 or 1 to 3. 



In the course of the experiments of 1910 and 1911 various lots 

 of apples were examined carefullj^ for egg punctures, and the 

 totals recorded. The count of egg punctures was not verified by 

 examination of the pulp for the egg; it cannot be said, therefore, 

 that each puncture noted represented a fertile egg. The number 

 of larvae issuing is nevertheless interesting. These data are given 

 in Table 21. It will be seen that the apparent mortality of the 

 combined egg and larval stages, assuming that egg punctures 

 represent fertile eggs, ranges from 14.6 per cent, the lowest, to 

 100 per cent. The average for all the lots is 64.2 per cent. 



The Winter Sweets recorded in Table 17 were rather badly 

 infested. Others of the same variety, from the same neighbor- 

 hood, and growing under similar conditions, gave a count showang 

 10,523 punctures to 1,538 apples, an average of 6.7 per apple. 

 The number of larvae issuing from the 511 specimens recorded 

 in Table 17 was .281 per apple. 



Various lots of Early Harvests were under observation in 

 July and August, 1911, the egg punctures being counted and 

 the larvae issuing recorded. The apparent mortality ranged 

 from 20 to 68.6 per cent, with an average of 53.7 per cent. 



Similar results are apparent in experiments of others. Illing- 

 worth (34, p. 139) states that 300 Tolman Sweets and 100 North- 

 ern Spies were placed on soil in the open September 28. From 

 these only 3 adults emerged the following season. The probabil- 

 ity appears to the writer to be that very few larvae issued from 

 the apples placed in the open thus late in the season. It is stated 

 that other apples from the same lots placed in the glass insectary 

 gave an average of over three larvae per apple. 



Ross (55), in experiments with four varieties including sum- 

 mer, autumn, early winter and late winter, found a mortality of 

 combined egg and larval stages ranging from 77 to 98.7 per cent. 



