280 Trans. Acad. Sci. of St. Louis. 



are resting quietly, tlie female in the center of the dome. — 12:04. From 

 12:02 to 12:04 there has been a skirmish, all the insects fluttering and 

 knocking one another at>out. The female and male 27 are now wan- 

 dering about at the top, and it seems she is following this particular 

 male, which, by the way, is the younger and unmated. The female 

 has reached the highest point, and male 27, walking around her as he 

 clings to the wires, has completed perhaps six circles and apparently, 

 would continue, but male 6 interrupts him by constantly fluttering in. 

 the vicinity of the female, although he was quietly resting on the floor 

 when his rival, male 27, commenced this performance. After causing 

 this interruption male 6 again retires to the floor, apparently much 

 fatigued. Male 3 lies in the corner of the cage and takes no part in 

 the courtship. — 12:08. The female and male 27 are now the only ones 

 v/hich are still active. These two flutter wildly about each other. — 

 12:09 All quiet. — 12:11. Male 27, after taking his position directly in 

 front of the female and fluttering his wings while clinging to the 

 wires of the cage, has moved in this manner and completed seven or 

 eight circles around her. — 12:13. Both are now participating iu this 

 quaint performance. — 12:14. She now returns his courtesy, circling 

 about him as he hangs quietly from the wires. Males 3 and 6 have 

 made no further attempt at courting. — 12:18. The two insects are 

 gently touching wings. They are so near to each other that their 

 abdomens sometimes touch as they hang, back to back, from the dome. — 

 2:00. All have been quiet since 12:30, and mating has been expected 

 to take place at any time. Sometimes I have darkened the room for 

 many minutes at a time, but although the two insects are less than 

 an inch apart, they have quietly kept their places. — 7:30. As the 

 behavior has led me to expect, I find the female in coition with male 27, 

 the youngest of the three and the one which has been most persistent 

 in his courtship. 



Tlie very old male, as we liave seen, was tlie first to 

 tire, but lie had already mated and the wings were in 

 no condition for courting. Of the two unmated males, 

 the one loss than a day old proved himself better able 

 persistently to court than the one six days old. The 

 gradual dropping out of the game, one by one, of the 

 older males shows to a degree that the female does little 

 or no selecting. The behavior of male 6 shows that he 

 lost not because he was less eager or sexually unfit, but 

 because of his age.^ 



See foot-note, Experiment 6. 



