42 Trans. Acad. Sci. of St. Lows. 
are more often on the wing while the heavily ova-laden 
females remain secluded. In the data here offered, this 
chance is eliminated since the material was gathered in 
the cocoon stage, and usually every cocoon seen in the 
field was taken. 
From 1909 to 1911 we recorded the sex of 1214 Satur- 
nid moths (Journ. Exp. Zool., Vol. xii, p. 196), 653 males 
and 561 females, or a proportion of 116 males to 100 fe- 
males. In the years 1912 and 1913 we made further rec- 
ords on these moths, and from these data we have con- 
structed the following table: 
TABLE 25. 
Proportion of Sexes. 
Se eo AG eMnL ee te mudeoainn a0 SR too EOnen haere tee ee 
NUMBER PROPORTION 
Year SPECIES nc 
Males | Females} Males | Females 
S101 5, COREE No Poe rer ec 75 75 100 100 
1913 . OF Oenia: Plas 165 138 119 100 
1913 C. promethea, Fall River ...... 54 50 108 100 
$942:-)-Bs- californica, Cal. 23.2 i} vs 100 100 
1913 T. polyphemus, St. Louis....... 46 54 85 100 
1913 T. polyphemus, Augusta, Ga.... 316 285 146 100 
1913 T. polyphemus, Fall River..... 101 82 123 100 
1912 cS polyphemusy NeW Ace ck: 24 15 160 100 
1912 S. cecropia, St. L., R. des P 46 oo 140 100 
1913 S. cecropia, St. L. (fluffy)...... 44 35 126 100 
1918 S. Cecropis, St: Louis. a ic.c.. 174 161 108 100 
1913 S. cecropia, South St. Louis.... ig hoo 92 100 
1913 B. COChODiE NE Vs res ora os, 76 67 113 100 
1913 | S. cecropia, Fall River, Mass.... 5 ee 125 100 
OLA eee a eee 1226 | 1129 108 100 
These records of 2355 insects show the males again 
slightly in excess, 1226 males to 1129 females. By com- 
bining the data for the five years we find the total of 
3569 insects comprises 1879 males and 1690 females, or 
111 males to 100 females. We shall not presume to say 
how much significance may be attributed to the fact that 
