New York Agricultural Experiment Station. 



209 



tion between sex and size of larvae, but later developments of 

 the specimens under observation showed a small percentage of 

 males. Hence the facts recorded for the female larvie apply also 

 to the males. 



period of activity. 



Duration. — This period includes the time from birth until the 

 larva settles down. Its duration is influenced greatly by tem- 

 perature, as will be seen by comparing the following table, which 

 gives the record of larvae kept in the insectary and laboratory at 

 temperatures of from 70° to 76° F., with the records of larvoB 

 kept in rooms at lower temperatures, on page 311.^ 



Table I. — Length of Active Pkriod of San Jose Scale Larv^ in 



Inskctary and Laboraiory. 



The total number of larvaj recorded in this table is 747. None 

 of them settled in less than 12^ hours, while a number remained 

 active for from 36 to 48 hours, making the average number 27.7 

 hours, or a little over one day. 



The larvae probably remain inactive for a short time after birth. 

 To secure data on this point the scales were removed on Sept. 

 25 from three adult females and on Oct. 8, from three more. 

 Up to Dec. 13 the six gave birth to 263 larvae, 20 of which 

 were bom enclosed in the amniotic sack. Until the sack was 

 ruptured they appeared as minute, oval, light-yellow bodies. 

 Most of the imprisoned larvae did not succeed in freeing them- 

 selves, but those that successfully ruptured the sack escaped in 



