6 Journal of Agricultural Research voi. x, no. i 



1 91 6, the cages were taken from the cellar and placed in the open-air 

 rearing shelter. Thirty moths were alive at this date. It was noted 

 that many more males than females died during the winter. The moths 

 fed eagerly on diluted honey. On May 3 one pair mated and was iso- 

 lated in another cage. The record for this pair is given in Table II 

 (third generation). 



The experiment with this material, having been carried a full year, 

 was discontinued on August 30, 191 6. For some unknown reason the 

 moths which issued on June i deposited no eggs until June 10, and this 

 largely accounts for the overlapping (August 19 to 30, 191 6) of the life 

 cycle. 



During 191 6 the preceding life-history studies were verified by a dupli- 

 cate set of rearing experiments. The records are essentially the same as 

 those given in Table II, and the details will therefore be omitted. 



On May 3, 1916, a male and two females which had just issued from 

 winter quarters were captured about the blossoms of watercress and 

 confined in a cage. On May 4 the male mated with one of the females, and 

 the first eggs, 50 in number, were deposited on this day. On May 5,61 eggs 

 were deposited. The first eggs hatched on May 7, and from this material 

 the species was reared throughout the season. The dates on which the 

 adults of the seven successive generations issued are given in Table III. 



Table III. — Date of issue of adults of seven generations of Plutella maculipenms at 



Rocky Ford, Colo., igi6 



May 31 Adults of first generation issued. 



June 27 Adults of second generation issued. 



July 16 Adults of third generation issued. 



Aug. 4 Adults of fourth generation issued. 



Aug. 25 Adults of fifth generation issued. 



Sept. 22 Adults of sixth generation issued. 



Nov. 6 Adults of seventh generation issued. 



The adults of the seventh generation were confined in the usual way 

 and placed in the laboratory cellar on November 10, 191 6. At the time 

 this article was written, late in December, 191 6, these moths were hiber- 

 nating in excellent condition. 



REARING RECORDS AT PHOENIX, ARIZ. 



In addition to the life-history studies carried on at Rocky Ford, Colo., 

 the writer reared the diamond-back moth through one generation at 

 Phoenix, Ariz. There the cages were kept in an open, unheated hallway 

 where the temperature varied little from that prevailing out of doors. 



On December 30, 191 4, a few nearly mature larvae were collected from 

 turnips in a garden at Phoenix and confined. The first cocoons were 

 formed on January 2, 191 5, and the first larvae pupated on January 3. 

 The first adults, three in number, issued on January 20 and 21. These 

 moths were isolated in another cage. The record is given in Table IV. 



