THE CLOUDY-WINGED WHITE FLY: SEASONAL HISTOBY. 
101 
number of days required for development, shown especially by com- 
parisons of lots 1, 3, 6, and 7 of Table XXIII and lots 4, 5, 14, and 
15 of Table XV, is not the result of chance circumstances, but actually 
the result of slower general development under identical conditions. 
This fact is perhaps more forcibly brought out by the data in Table 
XXIV: 
Table XXIV. — Rate of development of A. citri and A. nubifera compared. 
Citri. 
Nubifera. 
Date. 
Instar 
1. 
Instar 
2. 
Instar 
3. 
Instar 
4. 
Instar 
1. 
Instar 
2. 
Instar 
3. 
Instar 
4. 
July 6 
P.ct. 
11.7 
2.1 
.7 




98.4 
8.0 
.6 
.6 






P.ct. 
88.3 
82.7 
10.5 
4.8 
2.9 


1.6 
92.0 
59.4 
4.3 
2.4 
.9 




P.ct. 

15.2 
89.8 
86.1 
20.6 
6.1 



40.0 
90.7 
17.2 
1.9 
1.9 



P.ct. 



9.0 
76.7 
93.9 
100.0 
6' 


4.4 
80.3 
97.1 
98.1 
100.0 
100.0 
P.ct. 
77.9 
6.9 
1.4 




99.6 
35.8 
2.9 
2.8 
1.8 





P.ct. 
22.1 
92.1 
30.8 
8.1 
5.9 
.8 

.4 
64.2 
96.0 
48.8 
20.9 
3.3 




P.ct. 

1.0 
67.8 
91.1 
62.2 
22.5 
14.9 


1.1 
48.3 
75.4 
90.0 
28.2 
12.7 
4.2 

P.ct. 

July 8 

July 12. . 

July 16 
0.8 
July 21. . 
31.9 
July 25 
76.7 
July 29 
85.1 

October 11 


October 23 

October 31 
1.8 
6.6 
December 3 
71.8 
87.3 
December 17 
95.8 
100.0 
In this table is shown the corresponding progress of growth of 
both species on various dates after egg deposition. The data con- 
cerning development during July refer to larvae hatching from eggs 
laid on June 16, 1909, and that during October, November, and 
December to larvae hatching from eggs deposited on September 18, 
1909. For these records, leaves on the same shoot were chosen for 
deposition of the eggs of each species; hence both species were subject 
to identical climatic and nutritive conditions. 
A study of the data in Tables X and XXI will also prove that the 
same statements made for A. citri concerning the equalizing effect 
of winter on the length of the pupal stage for wintering-over pupae 
are equally true for A. nubifera. The data show at a glance that 
eggs deposited in late October are capable of producing adults the 
following spring as early or even earlier than eggs deposited a month 
or, as sometimes occurs, five months earlier. 
SEASONAL HISTORY. 
Generations of the Cloudy-winged White Fly. 
Aside from the fact that the adults of this species have never been 
seen by the authors on wing during January and early February, as 
have those of A. citri, there being therefore no winter generation 
