SAN JOSE SCALE INVESTIGATIONS. L* 
THE DEVELOPMENT OF THE FEMALE. 
V. H. Lowe anp P, J. Parrorr., 
SUMMARY. 
The females were found to pass through three well-defined 
periods during development: The period of activity which fol- 
lows very soon after birth and during which they move about 
freely; the period of growth, at the beginning of which they 
insert their mouth parts into the tissue and begin to suck the 
sap and to form the scale; and the period of reproduction, at 
the close of which they die. 
The young scale insects under observation remained active for 
an average period of 27.7 hours at temperatures above 70° F. 
Temperatures below 60° F. caused them to settle very quickly. 
During the period of activity the larvze can cling to insects of ; 
various species and may be carried by them to new localities to 
which these larger insects happen to go from the infested trees. 
The duration of the period of growth was found to average 49.5 
days. Four distinct stages in scale formation were apparent: the 
cottony stage, the tufted stage, the black stage and the mature 
stage. 
The temperature experiments showed the larve to be unable 
to develop at an average temperature of 35° F., but able to 
develop to the black stage at a temperature of 45° F. Adult 
females were able to survive this temperature three months and 
to produce young soon after being removed to a temperature of 
70° F. At 58° F. some of the larve developed to the adult 
stage. 
*Reprint of Bulletin No. 193, 
