December, '17] SCIENTIFIC NOTES 563 



The Indian Meal Moth, Plodia interpunctella Hubn., in Candy and Notes on Its 

 Life-History. During January of this year there was brought from San Francisco 

 to the Parasitology Laboratory of the L^niversity of Cahfornia a quantity 

 of chocolate-coated marshmaUow candy thoroughly infested with the larvse of 

 Plodia. The candy was badly "worm eaten" and soiled with webs and castings. 

 The manufacturer reported considerable damage done to candy stored in fancy 

 pasteboard boxes. Evidently the eggs of the moth had been deposited on the candy 

 either just before packing or before the paper boxes were closed. 



A number of the moths were reared from the larvae, and several life-history ex- 

 periments were undertaken. 



The moths were hberated in a screened cage in which a small quantity of candy 

 was exposed. The cage was then placed in an artificially heated insectary with 

 temperature ranging from 22° to 26° C. Egg deposition took place at night, and the 

 minute, glistening whitish eggs, not over twelve to fifteen per female for the cases 

 observed, were deposited in haphazard fashion directly on the candy near the under 

 side of each piece. The individual pieces of candy rested in fancy paper cups. The 

 incubation period was about forty-eight hours. 



The very tiny larvae soon ate small pits in the candy and gradually became hidden 

 within a cavern. WhUe growth was very rapid it was found necessary to cease 

 observations before the entire larval period was finished. By comparison with 

 younger larva; collected from the originally infested candy and putting the beginning 

 and final observations on the two groups together, it becomes e\'ident that the active 

 feeding period probably requires not less than four weeks. 



Accurate observations on the original larva; show that the fully gro^\Ti individuals 

 leave the candy and crawl into corners or cre\aces where they pass a prepupal period 

 of from nine to twelve days, during which time they spin a crude web in which 

 pupation takes place. The pupal period requires from ten to fourteen days under 

 the temperature conditions above noted. On the other hand the pupal period 

 requires from twenty-four to twenty-eight days under room temperature varying 

 from 15° to 19° C. 



Thus it will be seen that the life-history of Plodia interpunctella requires about 

 forty days for its completion in a maintained temperature of from 23° to 26° C, 

 and that this insect may be of considerable importance to the candy maker. 



Wm. B. He RMS, 

 University of California. 



