Rail — Sexual Selection Experiments in Cecropia Moth. 291 

 Experiment 19.— May 4, 11 :30 A. M. 



c^l8. Age 5 days 22:40 hours. 



(^29. Age 5 days 0:40 hours. Antennae removed. 



5 76. Age 1 day 20:50 hours. 



Object. — To determine whether, of two males, the nor- 

 mal or the antennaless one will be the favored or suc- 

 cessful mate. 



Results. — May 11, 9:00 A. M. They have heen observed many times 

 each day for seven days, but mating has not occurred. Thinking that 

 the fault may lie with the female, female 107, aged 15 hours, is intro- 

 duced. May 19. For eight days these have been together without mat- 

 ing. Male 18 dies. 



Experiment 20.— May 4, 10 :00 P. M. 



c^63. Age 3 days 6:10 hours. Wings removed. 

 c?38. Age 5 days 8:00 hours. 

 9 78. Age 2 days 5:20 hours. 



Object. — Will the female choose the young, wingless 

 male, or the old normal one? ' 



Results. — May 10, 7:00 A. M. No mating has yet taken place. This 

 may be due to the cold weather.— 9:00. The two males are now removed 

 and male 109, of unknown age, is placed in their stead. — May 12, 8:00 

 A. M. This pair is found in coition. 



Experiment 21.— May 5, 10 :00 A. M. 



9 79. Age 2 days 17:10 hours. 



c?61. Age 3 days 18:10 hours. Previously mated. This is 

 the insect with red abdomen, described in Experi- 

 ment 12. 



Object. — To see whether, under favorable conditions, 

 this male will again mate, having left off mating only 

 two hours ago. 



Results.— May 9, 10:00 P. M. Up to this time, mating has not 

 occurred. The low temperature for the five days may be the cause 

 of their lazy behavior. At this time male 35 (age 10 days 8:30 hours) 

 is introduced. May 11, 11:00 A. M. No mating has yet taken place. 

 A marked male. 112, is introduced.— May 12, 8:00 A. M. The insects 

 are still found unmated. Thinking that the fault may lie with the 

 female, I now introduce female 103, about two days old. — May 14, Noon. 

 Still not mated. All the insects except female 79 and female 103 are 

 now removed, and male 109, an insect which has previously mated, 



