288 Trans. Acad. Sci. of St. Louis. 



rest. — 9:37. The female has been nervously fluttering for almost two 

 minutes. — 9:39. All are quiet; the female hangs nearer to male 58. — 

 10:10. The female is found to have vvandered to the other side of the 

 cage and is now nearer to male 41. At this time we see male 58 

 (wingless) creeping nearer and nearer to the female, and taking a 

 quiet but firm stand between her and his rival. — May 3, 8:00 A. M. 

 The female is found in copulo with male 58. 



The younger insect has again been successful in spite 

 of his wingless condition. 



Experiment 14. — May 1, 9:55 P. M. 



J 6. Age 9 days 7:25 hours. 

 ^ 7. Age 9 days 7:10 hours. 

 9 55. Age 1 daj-- 6:40 hours. 



Object. — To ascertain if a young female, given the 

 choice of two very old males both in apparently like phys- 

 ical condition, will select the one which is younger by only 

 15 minutes. 



Behavior. — 9:55. The three insects are placed together, and all 

 join in a general skirmish for two minutes. The two males then become 

 quiet while the female on the floor slowly moves her wings, and just 

 above her clings male 6. Soon male 7, clinging to the wire near the 

 floor, commences to beat his wings violently against the screening. — 

 9:58. Male 6 comes down and flutters about the floor and throws him- 

 self bodily against the female. — 10:00. Both males are quiet, and the 

 female continues slowly to fan the wings until 10:05. Now she flies to 

 the far end of the cage and with great force throws herself against 

 first one male and then the other. They both pay her no heed what- 

 ever, but very soon male 7 gently vibrates his wings. — 10:07. Male 7 

 flies to the female and then to the center of the dome, and there 

 remains. Male 6 lies quietly on the floor. — 10:12. The female follows 

 male 7 to the top and flings herself against him repeatedly. Twice he 

 has been knocked to the floor, but each time has promptly remounted. 

 The two now go wheeling and fluttering about each other alternately in 

 circles never quite complete. Male 6 is apparently out of the game, 

 and all are now quiet. May 2, Midnight. The day has passed without 

 an approach to mating. — May 3, 8:00 A. M. The female is found in 

 copulo with male 7, the younger by ]5 minutes. 



Experiment 15.— May 3, 12 :22 A. M. 



(^62. Age 1 day 8:32 hours. Exceptionally small; wings de- 

 formed {see Experiment 11) ; has severed connection 

 with female 2:22 hours ago. 



cjes. Age 1 day 8:32 hours. Large and beautiful. 



9 54. Age 2 days 9:07 hours. 



