Rau — Sexual Selection Experiments in Cecropia Moth. 281 

 Experiment 6.— April 29, 11:10 P. M. 



$ 37. Age days 9:38 hours. 



(5*30. Age days 12:20 hours. Wings removed. 



cJ 6. Age 7 days S:40 hours. 



Object. — ^To ascertain whether a virgin female will 

 mate with a yomig wingless male or an old normal one. 

 If color plays a part in selection, we should see the old 

 perfect insect chosen; if vitality decides her choice, we 

 should expect to see the j^oung wingless male mate. The 

 old, normal individual will have an equal or perhaps bet- 

 ter chance to mate in competition with a young wing- 

 less one. 



Behavior. — 11:10. The female hangs quietly from the dome. Male 6, 

 which has been passive for the last twenty hours (since he became 

 so in Experiment 5) becomes extremely active as his cage is brought 

 near that of the female. Male 30 rests upon the floor, while male 6 

 flutters wildly about the female. — 11:18. This continues until the 

 female falls, or perhaps is knocked to the floor. Here she remains, 

 gently moving the wings, while male 30 crawls to the top. The slow 

 movement of her wings soon evolves into wildest fluttering about the 

 floor in company with male 6. Presently the pair creep to the top 

 of the cage and continue their activity for one minute, and then fall 

 to the floor. The female and wingless male 30 again reach the top 

 of the cage, where the fluttering is extremely active on the part of the 

 female, and as lively as could be expected of the wingless male. At 

 intervals the male comes to a complete rest and the female circles 

 about him, and again both hang for a half minute or so at a time, so 

 close together that the ventral surfaces of their abdomens touch, and 

 gently move their wings, or remnants of such. During all this the 

 normal but aged male 6 lies quietly on the floor, making no attempt 

 to win the female. — 11:30. All are quiet; male 30 hangs from the 

 top of the cage about five inches from the female. — 1:30. Same. — Morn- 

 ing. The female and the young, wingless male 30 in copulo, while the 

 older perfect male, although equally eager, has lost.^ 



Experiment 7. — April 29, 9 :45 P. M. 



9 32. Age days 10:45 hours. 



(^27. Age 1 day 3:55 hours. I^eft off mating 15 minutes 

 previously. 



'Although male 6 appeared sexually excited in all three experiments, 

 5, 6 and 14, the fact that he lost out in all might suggest that he was 

 In some unknown way defective. In all of the trials he was matched 

 against younger rivals. 



