48 



THE SAN JOSE OK CHINESE SCALE. 



membrane. At from thirty-three to forty days the larvse again begin 

 to make their appearance. 



The adult female, prior to the development of the j^oung, measures 1 

 millimeter in length and a little less in breadth, and is pale yellow, with 

 transparent spots near the margin of the body (fig. 6). 



The length of a generation is determined b}^ the female and, as 

 shown b}^ the above record, covers a period of from thirty-three to 

 forty days. Successive generations were followed carefully thruout 



cc ' >,. 



Fig. 6. — Adult female San Jose scale {Aspidiotus perniciosus) before development of eggs: a, ventral 

 view, showing very long sucking setse; 6, 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 possibilit}^ of a partial fifth genera- 

 tion. On a number of potted trees a single overwintered female was 

 left to each tree. After the full progen}^ 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. 



