290 Trans. Acad. Sci. of St. Louis. 



Experiment 17. — May 4, 10 :30 A. M. 



2 72. Age 1 day 19:58 hours. Wings removed. 

 $ 73. Age 1 day 19:55 hours. 



(^ Age 



Object. — Same as Experiment 16. 



Results. — May 10, 8:00 A. M. Mating having not taken place dur- 

 ing six days, a stray male 108 is introduced. — May 11, 10:00 A. M. This 

 stray male found in copulo vi'ith female 73. 



No doubt the cold weather was the cause of the slug- 

 gishness of this group, and perhaps when the weather 

 became warmer the male was too old to mate. The mean 

 temperature, according to the United States weather 

 reports, for May 4 to 9 inclusive, was 49°, 52°, 52° 

 50°, 51° and 65° F. The experiment shows that perhaps 

 this or some fault of the male kept them from mating, but 

 under proper conditions on May 11 the stray male chose 

 the perfect insect, which was a few minutes the younger, 

 in preference to the wingless one. 



Experiment 18.— May 4, 10 :30 A. M. 



2 68. Age 2 days 15:30 hours. In a badly dilapidated condi- 

 tion, one leg entirely gone and the tarsus lacking on 

 all of the others; the wings are deformed from hav- 

 ing hardened before being fully inflated, — hence it 

 can neither cling to the wire cage nor fly. It 

 emerged from a cocoon which lay beneath several 

 others, and in making its way to the top the moist 

 body collected much filth. 



o 48. Age 3 days 21:25 hours. Large. 



J' 65. Age 2 days 17:30 hours. 



Object. — To ascertain if the male will mate with the old 

 normal female or the younger but much dilapidated one. 



Results. — May 10, 8:00 A. M. The male found in copulo with 

 female 48. 



The cold weather (see Experiment 17) may have hin- 

 dered mating. This is the first instance in which a male 

 has mated with an older female in preference to a 

 younger one. But when we remember the crippled and 

 filthy condition of the latter, we can easily see why mat- 

 ing was probably impossible. 



