284 Trans. Acad. Sci. of St. Louis. 



In this case the male which mated was the one of dull 

 color, small size, and damaged wings, but younger age 

 than its rival. The persistence of the female in follow- 

 ing him shows the exercise of choice on her part. In 

 other of our experiments we have been unable to detect 

 much evidence of such choice. But in this, our cleaj-est 

 case, her choice was quite contrary to what theories would 

 lead us to expect. In the next experiment this fine male 

 mated. The fact that the male proved to be perfectly 

 good only makes her choice the more perplexing. 



Experiment 10.— May 1, 7 :25 P. M. 



$ 57. Age days 5:55 hours. Small; expanse of fore-wings, 



12.5 cm.; width of abdomen, 1.4 cm.; length of body, 



3.6 cm. 

 5 54. Age 1 day 4:10 hours. Large, beautiful; expanse of 



fore-wings, 17.5 cm.; width of abdomen, 1.8 cm.; 



length of body, 4.2 cm. 

 cJ31. Age 2 days 8:30 hours. 



Object. — To see whether the male will exercise any 

 choice, and if so whether the very small, or a large beau- 

 tiful female will be favored. 



Behavior. — 7:30. For five minutes all have constantly fanned the 

 wings gently to and fro as they cling to the side wires. Now the 

 male crawls to the top and his movement becomes more rapid; he flut- 

 ters down to where female 54 is resting and flies against her several 

 times. She now remains motionless in spite of the rough attentions 

 of the male. Next he comes near beside her and strikes her with his 

 wings, then flits to the top of the cage only to return at once and 

 resume his position so that his vibrating wings beat against hers. — 

 7:35. The male takes his position directly in front of female 54 and 

 there remains motionless. Meanwhile the small female 57 clings to 

 the opposite side of the cage and fans the wings briskly for a minute 

 and a half, then gently creeps closer and closer to the male. As she 

 nears him, her wings flap violently; she beats her wings against hiS) 

 until she falls to the floor, flies away, and back at once to him. Again 

 she flutters to the floor, passing blusteringly between the male and 

 female 54, and twice again in precisely the same manner. It appears 

 that by thus cutting in between them she is attempting to place dis- 

 tance between the male and her beautiful rival, but throughout the 

 performance female 54 stands immovable. — 7 : 40. The two females have 

 settled down on either side of the male, so near that in occasionally 

 moving their wings they often brush his. Prom the behavior of the 



