32 REPORT OF SEAECH FOR ENEMIES OF CITRUS WHITE FLY. 
and averages about 15 inches. Taken as a whole the climate of the 
Punjab is very comparable with that of portions of the arid south- 
western United States. 
The writer's observations were confined almost entirely to the 
year 1911, during which conditions were somewhat abnormal because 
of the almost total failure of the rains during the monsoon in the 
plains of northern India. The prevailing extremely high temperature 
and low humidity throughout the summer (with the exception of two 
periods of very light rainfall) gave excellent opportunity for observing 
the effect of high temperature on the development of the white fly, 
as well as the effect of humidity on its development and emergence. 
Throughout the period between April and September the humidity 
continued so low that at no time was foliage noticeably moistened by 
dew except in a few instances following precipitation. Heavy dews 
occur during the autumn and winter months, yet they are much 
less heavy than in Florida. 
With these considerations regarding Indian weather in mind, an 
attempt will be made to specify its effect on the development of the 
white fly during 1911. It is quite probable that the emergence of 
the first brood at Lahore took place about the 1st of April. By May 
1 it appeared that practically all eggs had hatched, while the insects 
were in the earlier stages of development. The temperature during 
the latter half of April averaged about 82° F. Development con- 
tinued throughout May, and by June 11 the insects were mostly in 
the thickened pupal condition or approaching maturity. As com- 
pared with that of Florida, development thus far had been about 
normal. The mean temperature from May 1 to June 11 was 93° F. 
During the period, June 11 to 15, about 2 inches of rain fell, while 
the humidity, which had averaged about 39 during the preceding six 
weeks, now rose to an average of 74. This moisture apparently 
hastened the development of the pupse. A few of the more advanced 
individuals changed to adults and emerged about 10 days after the 
rain. Almost immediately following this period of precipitation the 
temperature rose, while the humidity returned to normal. This 
return to previous hot, dry conditions appeared suddenly to check 
further development, but such pupae as had already changed to 
adults began emerging on June 25, 10 days after the last rain. A 
very light shower of rain fell on June 26 and appeared to bring out all 
adults ready for emergence. Within four days practically all adult- 
flies had disappeared from the hedge plants. 
This hot, dry weather continued throughout July up to August 20. 
Slight thunderstorms on July 13 and 14 moderated the temperature a 
few degrees. The very dry, hot atmosphere immediately preceding 
and folio whig these rains, as well as the sunshine between showers, 
almost immediately dissipated any marked change of the tempera- 
