30 Trans. Acad. Sci. of St. Louis. 
period of their growth and spin these cocoons about 
themselves. After a very brief period in the cocoons the 
larvae transform into pupae. It is in this pupal stage 
that the development of the eggs occurs. When a female 
emerges as an adult, Nature has already prepared her 
for her brief life by having all of the eggs matured and 
ready for oviposition. In some of the longer-lived Lepi- 
doptera, some of the eggs are being deposited while oth- 
ers are maturing. Here, however, the eggs are all ready 
to be laid when the insect emerges from the cocoon, and 
when these are laid, or sometimes before all are depos- 
ited, she dies. With conditions such as these it is easy 
to tell precisely the total number of eggs carried by each 
individual.? Of course, we assume that the total num- 
ber of eggs carried by each female is influenced by the 
home conditions of the larva, that is, food, climate and 
moisture, and that the local conditions of the last few 
months of pupal life, spent at St. Louis, could not in 
any way influence the number of its eggs. 
During 1911-13 we made a study of the eggs carried 
by the 504 individuals of 19 lots of these moths. (See 
Table 19.) 
For convenience the numbers of eggs carried were 
thrown into groups of twenty, but the averages in the last 
column were reckoned from the actual numbers. The 
table gives some interesting comparative details. For the 
five lots of Polyphemus material the means vary from 
198 to 293 eggs. The mean number of eggs carried by 
the Fall River Polyphemus of 1913 equaled that of St. 
Louis for the same year. The St. Louis lot for-1911 had 
the largest average while the New York 1912 lot ranked 
second, but for the last two the numbers of observations 
were small, and one must be cautious not to lay too much 
weight upon this evidence. The Polyphemus from Au- 
gusta, Ga., had the smallest average number of eggs, 198. 
7 This is done by adding the number of ova deposited to the number 
retained as revealed by dissection after death. 
