72 Trans. Acad. Sci. of St. Louis. 



before. In the two lots the proportion of fluffy cocoons 

 to compact ones was as follows : 



Year 



1912-13 



1913-14 



These figures show that in 1912-13 the baggy cocoons 

 occurred in, approximately, the proportion of 1 to 3 

 and in the following winter 1 to 10. Our previous work 

 showed the proportion for 1910 to be 1 to 4, and for 

 1911, 1 to 6. 



The sexes, recorded at the time of the emergence of 



the insects from the fluffy cocoons, were as follows : 



Year Males Females Total Observed 



1912-13 44 35 79 



1913-14 10 14 24 



These notes again show that the fluffy cocoons are 

 by no means rare, and that both sexes emerge from 

 them. It is however of peculiar interest that not one 

 fluffy cocoon was found in a lot of 300 cocoons from 

 South St. Louis or the lot of 200 from New York. 



We shall have to seek further for the factors con- 

 trolling this fluffy condition. May it be that it is due 

 to the mere fact that some larvae are more vigorous than 

 others, this greater vigor being due to the amount of 

 food consumed, and that this greater vigor plus the 

 surplus material in the body may express itself in the 

 large weaving capacity? 



DUBATION" OF PUPAL STAGE IN SAMIA CECROPIA. 



Previously 19 we found the pupal period of S. ceropia 

 to vary from 312 to 324 days. To this we wish to add 

 the following data : 



Sex Spinning Completed Emerged Duration 



5 July 10, 1913 May 23, 1914 317 days. 



J July 13, 1913 May 23, 1914 314 days. 



$ July 18, 1913 May 25, 1914 311 days. 



J 1 July 15, 1913 May 27, 1914 316 days. 



$ June 15, 1913 May 23, 1914 342 days. 



is Psyche. 20: 204, 1913. 



