Rau—Longevity in Saturniid Moths. 45 
a high frequency corresponds to a high temperature on 
either the same or the preceding day, and a low fre- 
quency the corresponding reverse. It is only natural 
that the parallelism fails after June 10, when at the close 
of the season only a few stragglers are left to emerge. 
L'wo explanations of this phenomenon of priority of 
male emergence present themselves. The one suggested » 
by Darwin seems at first thought plausible; that among 
insects as well as among other groups of the animal 
kingdom the males emerge or arrive at maturity a little 
earlier than the females in order that they may have 
time to travel about and seek out mates, and that the 
first upon the field will win the mates and leave offspring 
to perpetuate their habits. In this way it is an adapta- 
tion for the good of the species. But on the other hand, 
in species like these where the duration of the entire life 
is but a few days, even these 2 or 3 days of priority of 
the male may suffice to deprive him entirely of a mate. 
Hence if this,condition exist as a natural law it is at 
least subjeet’ to many drawbacks and defeats by other 
conflicting factors. The other explanation is that the 
duration of the pupal life of the male is shorter than 
that of the female, owing to the fact that the female has 
the large mass of ova to produce, and that this difference 
in time required for development becomes apparent at 
this particular point in the life of the individual. 
Ferritity or Satrurnup Eaas 1x Reiation To THE 
Matine Pertop. 
. 
INTRODUCTORY REMARKS. 
The Saturniid moths, at least the ones with which we 
have worked, spend much time in mating. The Cecropia 
moth spends from 10 to 48 hours in eopulo, or 21 hours 
on an average? We have found that a normal mating 
for all of these species Cynthia, Polyphemus, Cecropia 
or Californica, consists of a continuous period in eopulo 
12 Trans. Acad. Sci., St. Louis, 20: 309, 1911. 
