EFFECTS OF TEMPERATURE ON WHITE FLY. 29 
few adults remained in flight, while the first eggs deposited were 
hatching. All eggs were hatched by October 5 and by October 20 
many insects had reached the pupal stage. 
Investigations at Raj pur and Saharanpur revealed conditions com- 
parable with those at Lahore. Observations throughout northern 
India in November of the previous year (1910) showed the insect 
at that time to be in the pupal state. From a consideration of these 
conditions found in two different years it is evident that the white 
fly passes the winter in northern India as a pupa. 
Number of Broods of the Citrus White Fly. 
It has been stated by Morrill and Back that while there may be 
in Florida from three to six generations, adult flies are found in 
greatest abundance only during three more or less distinct periods, 
or generally speaking, there are three broods of white flies each year. 
Strictly speaking, there is great irregularity of breeding and overlap- 
ping of generations so that adult white flies may be found in varying 
numbers at all times except during the colder periods of winter. In 
all this irregularity, however, theire stand out in prominence three 
general broods — a spring, a summer, and an autumn one. 
Turning to northern India we find a different condition. Here 
there were two very distinct broods on citrus trees in 1911, adults 
of the first emerging in early April and those of the second during the 
first part of September. So far as the writer's observations extended 
these broods were sharply denned and without overlapping genera- 
tions. In fact, so sharply defined were these two broods that no 
adult flies were seen outside of the two normal periods of emergence 
with the exception of a very few during three to four days in June. 
The latter emergence was due to a preceding period of high humidity 
accompanied by slight rains. 
The Effects of Temperature on White-fly Development. 
The climatic conditions of the plains of northern India are very 
different from those of Florida, and the resultant effect on the devel- 
opment of tne white fly is equally apparent. 
Whereas the winters hi the Punjab of India average colder than in 
Florida the summers are very much hotter. During the months of 
July and August the average daily mean temperature in central 
Florida is 82° F., while during the same period in 1911 at Lahore it 
averaged 96° F., or 14° higher. The average daily mean tempera- 
ture at Lahore for the months of May, June, July, and August was 
94° F. and the average maximum temperature for the same period 
was 107° F. Such high temperatures have naturally a deterrent 
effect on insect development. Most of these days are bright and 
sunshiny, and so penetrating is the direct action of the sun that 
