Rau — Longevity in Saturniid Moths. 71 



In addition to these, many other pairs were left in 

 copulo during the evening, but early the next morning 

 they were found to have severed. 



Judging from the short life of the Prometheas, and 

 knowing that the Cecropia moths are mostly monogam- 

 ous, we might almost assume that this species is also 

 monogamous. From a small number of experiments 

 this seems to be true, and in the case of all of the 24 

 females which mated, the males were allowed subse- 

 quently to remain in the cage. In these cases a second 

 mating was never observed, although the usual period 

 of mating is so short that mating could have occurred 

 at a time when constant watching was impossible. 



Some slight interest may be attached to the age of the 

 insects when mating began, to see at how early or how 

 late an age the moths were capable of mating. 



Age Females Males 



6 hours or less 1 1 



6 to 12 hours 8 9 



12 to 18 hours 1 



18 to 24 hours 1 



1 to 2 days 1 1 



2 to 3 days 3 



3 to 4 days 2 1 



4 to 5 days 



5 to 6 days 1 



This table shows that 21 out of the 30 insects of both 

 sexes mated before 24 hours of age. 



FLUFFY CECROPIA COCOONS. 



In 1911 18 we discussed the nature and abundance of 

 the cocoons of Samia cecropia. During the past two 

 years we have made additional observations which are 

 interesting since they substantiate the earlier ones. 



During the winters of 1912 and 1913 cocoons were gath- 

 ered from the Eiver des Peres region, the same area as 



is Psyche. 18: 168-170,1911. 



