276 University of California Publications. [Entomology 



Life-History. — Eight of the twelve eggs used in the experi- 

 ment hatched within four days, while the remaining four re- 

 quired five days, even though the temperature conditions were 

 practically identical throughout the ten days during which the 

 three clusters of eggs were incubating. The first larval period 

 required 3.3 days, the second 2.3 days ; the third 2.8 days ; the 

 fourth 4.7 days ; and the pupal stage 3.5 days ; giving a total of 

 21 days from egg to adult. The variations in time within the 

 periods were, first larval, three to four days ; second larval, two 

 to four days ; third, two to three days ; fourth, four to six days ; 

 and in the pupal period, three to four days. The range in the 

 total life-cycle was from twenty to twenty-three days, showing 

 a rather unusual uniformity. 



