Jttly 2, 1917 



Life History of Plutella maculipennis 



The moths of the seventh generation, which issued on October 3 and 4, 

 30 in number, remained in the cage in which they were reared until 

 November 9. They fed on diluted honey, but deposited no eggs. On 

 November 9 they were transferred to a cage containing a dead cabbage 

 plant and 2 inches of moistened soil and placed in the laboratory cellar. 

 They crawled in among the dead leaves or clung to the underside of the 

 cloth cover of the cage, becoming semidormant throughout the winter. 

 From December, 1914, until March, 1915, during the writer's absence, 

 the cage was neglected and the soil became dry, which was apparently 

 detrimental to the moths, as several died. 



On April 5, 191 5, the cage was taken from the laboratory cellar and 

 placed in a slightly heated room in the laboratory. Six moths were alive 

 and apparently in good condition. They remained partially dormant 

 until April 30, when they became active and began to feed. On May 2 

 the first eggs were deposited and others were deposited at intervals until 

 May 14. Illness at this time occasioned the loss of these eggs. 



REARING RECORDS FOR I915-16 



On August 18, 1 91 5, life-history studies were resumed with fresh 

 material collected in the field. Merely for the sake of convenience the 

 first brood reared from this material will be arbitrarily designated the 

 "first generation," although in reality it is the sixth generation which 

 developed in 191 5. The records of the seven generations of 191 5-1 6 are 

 given in Table II. 



Table II. — Record of the generations of Plutella maculipennis at Rocky Ford, Colo,, in 



1915-16 



a Or Nov. 3. 



Fifty-two adults, about equally divided as to sex, developed on 

 November 2 and 3. These moths were confined in battery jars contain- 

 ing moistened earth and dead cabbage plants, and on November 10 

 were placed in the laboratory cellar. Throughout the winter the cages 

 were examined and the soil moistened at frequent intervals. On May 2, 



