294 Trans. Acad. Sci. of St. Louis. 



Object. — ^To see if an already mated male will remate ; 

 and if so, will he select the younger of two good females ? 



Results. — May 13, 8:00 A. M. The male found in copulo with 

 female 106. 



iThis again shows that the male will remate with a 

 young female if he himself is also quite young. In this 

 experiment we see the young female being preferred. 



Experiment 29.— May 18, 10 :30 A. M. 



(^ 122. An unknown insect attracted to the laboratory by the 



females. 

 $ 91. Age 8 days 21:44 hours. 

 $ 119. Age 1 day 20:10 hours. 



Object. — To see whether the male will mate with the 

 female 9 days of age, or the one of 2 days. 



Results. — May 19, 8:00 A. M. The male actually found in copulo 

 with the much older female. 



Experiment 30.— May 21, 10:00 A. M. 



cJ129. Age and history unknown. 

 $ 95. Age 11 days 20:15 hours. 

 $ 127. Age day 22:00 hours. 



Object. — To see if the female 1 day old will be chosen 

 in preference to the one 12 days old. 



Results.— MaiY 22, 8:00 A. M. The male in copulo with female 127, 

 the younger. 



Experiment 31.— May 28, 3 :00 P. M. 



9 123. Age 10 days 2:50 hours. In spite of age, has not yet 

 deposited any eggs. 



$ 128. Age 8 days 2:00 hours. Has deposited some unfertil- 

 ized eggs. 



c^l31. Age day 1:15 hours. 



Object. — To see whether the older virgin female or the 

 younger one, which has oviposited, will be the chosen 

 mate. 



Results. — May 29, 8:00 A. M. The male found in copulo with 

 female 128, the younger. 



