48 
THE SAX JOSE OR CHINESE SCALE. 
membrane. At from thirty-three to forty days the larvae again begin 
to make their appearance. 
The adult female, prior to the development of the young, measures 1 
millimeter in length and a little less in breadth, and is pale yellow, with 
transparent spots near the margin of the body (tig. 6). 
The length of a generation is determined by the female and. as 
shown by the above record, covers a period of from thirty-three to 
forty days. Successive generations were followed carefully thruout 
CO 
i*w 
r 
Fig. 6.— Adult female San Jose scale (Aspidiotus perniciosus before development of eggs: o, ventral 
view, showing very long sucking setae; b, anal plate, showing characteristic ornamentation of edge. 
Greatly enlarged (from Howard and Marlatt). 
the summer, and it was found that at Washington four full generations 
are regularly developed, with the possibility of a partial fifth genera- 
tion. On a number of potted trees a single overwintered female was 
left to each tree. After the full progeny of this individual had gone 
out over the tree, all were removed again, except one of the oldest and 
fertilized females. This method was continued for each generation 
thruout the breeding season. Some interesting records, tabulated 
below, were thus obtained, which indicate the fecundity of the females 
as well as the number of generations. 
