1908] 



Biological Notes on Potato Beetle 



163 



THE ADULT. 



I. Length of Life in Confinement. 



a. hi pairs normally reproducing. The results obtained on 

 this point are important, indicating as they do a very much longer 

 adult life than formerly believed, and even going beyond the 

 records of Tower (1906, p. 231, table 103). With Tower in nor- 

 mally reproducing adults, over 88 per cent, had died by the 

 twenty-fifth day, 67 per cent, by the twentieth day. My experi- 

 ments were necessarily on a much smaller scale, yet all of the 

 pairs kept b}' me, and in fact all of the adults recorded in follow- 

 ing, confined together, lived considerably over the periods 

 recorded by Tower. For instance, the hibernated pairs of the 

 wintering generation, captured mating at 4 p. m., May 29th, 

 and at once confined and supplied daily with food, reproduced 

 continuously and did not commence to die until after the middle 

 of the following August; the male of Pair No. 2 died on August 

 i6th, the female of Pair No. i on Augu.st 28th, after not quite 

 three months, the female of Pair No. 2, not until October 6th, 

 much over four months after capture and the male of Pair No. i 

 did not die until April 6, 1908, after it had been in hibernation 

 since July 2, 1907, emerging on February 26, 1908. 



As Tower points out (1906, 1. c), these records may be due 

 to exceptionally long-lived individuals. Table VII summarizes. 



TABLE Vn. Length of Adult Life in Confinement, Normally Reproducing. 



h. Mixed sexes, without food. A single lot of adults, sur- 

 vivals of 30 larvae hatching at 5 a. m., June 25th, and produced 

 by Pair No. 2 of the hibernated individuals, and emerging from 

 the soil in a large glass jar at 12 130 p. m., July 17th, were imme- 

 diately fed and kept supplied with food until mating began on 



