THE CANADIAN ENTOMOLOGIST 



18- 



It will be seen from the table that 227 pupae were under 

 observation and that the minimum length of the pupal instar was 

 9 days and the maximum length 16 days, while the average was 

 12.6 days. 



During the first part of the investigation no data were kept 

 on the sexes, but in the later stages of the observations determina- 

 tions of sex were made in case of the last 155 individuals, of which 

 70 were females and 85 males. No data, however, were secured 

 on the pupal instars of the two sexes separate from each other. 

 The average' of 12.6 days, therefore, is that of males and females 

 combined in probably about the proportions shown by the fore- 

 going figures concerning the last 155 individuals. 



The maximum and minimum temperatures, obtained from the 

 Weather Bureau at Rochester, N. Y., are given for each day 

 covering the period of the experiment. Our own maximum and 

 minimum thermometer was evidently placed in a position which 

 did not give the normal temperatures, and we, therefore, took the 

 records of the Rochester Observatory. Rochester is eighteen miles 

 southeast of Hilton, where the field laboratory was situated, and 

 the temperature conditions at the former city would probably fairly 

 represent those obtaining at Hilton, although the altitude of Hilton 

 is 284 feet, while that of Rochester is 523 feet. At any rate, they 

 would be more representative than the temperatures recorded by 

 our own thermometer under the apparently abnormal conditions 

 in which it was placed. 



The difference in the length of the pupal instar as recorded in 

 California by Davidson and in New York as shown by the foregoing 

 data is interesting. More data, however, on meteorological con- 

 ditions in the two regions will be necessary before any very definite 

 conclusions may be drawn. 



*From the Records of the Weather Bureau at Rochester, N. Y. 



