Rau — Longevity in Saturniid Moths. 43 



the proportion for all Saturniids observed in the first 

 period, 1909-11, was 116 males to 100 females, while the 

 records for 1912-13 show a proportion of 108 males to 

 100 females. 



The Peioeity of Male Emeegence. 



In a study of the duration of life from the standpoint 

 of efficiency for the perpetuation of the species, the fact 

 that in practically all of our Saturniid material the males 

 emerged from 1 to 5 days in advance of the females is a 

 point worthy of thoughtful consideration. Here is the 

 average priority 11 of the males of each population over 

 the females: 



TABLE 26. 



Callosamia promethea, Fall River male priority, 3.07 days. 



Philosamia cynthia, New York male priority, 2.64 days. 



Philosamia cynthia, Philadelphia male priority, 1.09 days. 



Samia cecropia, New York male priority, 3.47 days. 



Samia cecropia, St. Louis (fluffy) male priority, 4.98 days. 



Samia cecropia, St. Louis, River des Pgres male priority, 2.56 days. 



Samia cecropia, South St. Louis male priority, 1.84 days. 



Telea polyphemus, Augusta, Ga male priority, .23 days. 



Telea polyphemus, St. Louis male priority, 1.48 days. 



Telea polyphemus, Fall River female priority, 3.12 days. 



These means give us a concise index to the actual con- 

 dition occurring for the whole lot. For the details of 

 the rate of emergence throughout the season, and the 

 proportion of the sexes for each day, we present the data 

 in the following curves. (See Pis. I-V.) For making 

 these curves, the two groups of Cynthias, from Phila- 

 delphia and New York, were thrown into one lot, since, 

 if plotted singly, the numbers were too small and too scat- 

 tered upon the field to show the evidence clearly. For 

 the same reason the Cecropias from the fluffy cocoons 

 were combined with the rest of their lot, the River des 



ii The mean date of emergence of males and females was found, and 

 this is the difference between the two. 



