JOURNAL OF ENTOMOLOGY AND ZOOLOGY 49 



B. SEASONAL HISTORY 



The year naturally divides itself into the season of rainfall cor- 

 responding to winter and the summer or dry season, as there is no 

 marked seasonal change in this locality. The dry season in 1913 

 was extremely long and the wet season was short. Under such cir- 

 cumstances, the life history of the rose scale was worked out as 

 follows : 



1. The First Generation 



The female insects which reached the adult stage late in Decem- 

 ber, 1912, began the egg-laying in the early and middle parts of 

 January, 1913. The egg-hatching was first observed on January 

 13th, and was continued to the middle part of February. The 

 larval period lasted for about a month. Some of the young 

 females became full grown in March but most of them in the early 

 part of April. The larval growth was long and irregular because 

 the months of January, February and March in 1913 were cold 

 and wet. 



2. The Second Generation 



The adult females were observed laying eggs through April. 

 The egg-hatching was first noticed on April 27th in Palo Alto. 

 Hatching was continued from then until the middle of May and 

 became suddenly less toward the end of this month. The larval 

 period lasted through June, but a few reached the adult stage as 

 early as June 16th. A large number of young females became full 

 grown between June 20th and July 10th. The winged males began 

 issuing from the middle of June. Many young females of this gen- 

 eration were destroyed by a small hymenopterous parasite, which is 

 a common enemy of the rose scale in this locality. 



3. The Third Generation 



The egg-laying was observed mostly in the middle and latter 

 parts of July, and the egg-hatching was noticed abundantly toward 

 the middle of August. The young females reached the adult stage 

 toward the end of September, while the males had issued already 

 in the early part of this month. The egg-laying was commenced in 

 October and continued for about a month. 



