70 Trans. Acad. Sci. of St. Louis. 



mate in 1913, we selected a few cages containing a pair 

 each and introduced into each one a male Cynthia. In 

 four cases out of ten mating occurred, the female 

 Promotheas giving preference to the Cynthia males — 

 or perhaps yielding to their greater animation — and re- 

 mained in copulo 24, 12, 10 and 1 hours respectively. 

 The eggs from these four matings were cared for, but 

 all proved infertile. 



June 8 a male Cecropia mated with a female Cali- 

 fornica for 10 hours, but the eggs from this crossing 

 also were infertile. 



EATING OF EGG SHELLS BY T. POLYPHEMUS. 



We found that when the Polyphemus larvas remained 

 prisoners in the vials in which they had hatched from 

 the egg, they ate parts of many of the egg-shells. We 

 do not know whether it is customary for Polyphemus 

 to eat the shell after having emerged from it, or whether 

 this is done only in the event of scarcity of other food. 

 This practice was not indulged in by the Cynthias, 

 Cecropias or Californicas. 



CALLOSAMIA PROMETHEA. 



While the Promethea experiments were in progress 

 in 1911, almost every day at about 4 p. m. many free 

 males were attracted to the laboratory by the females, 

 and when they were placed inside the cages they lost 

 very little time before mating. Unlike the Cecropia 

 moth which mates just before dawn, the Promethea is in 

 copulo before sunset, and while the Crecopia remains in 

 mating on an average about 21 hours, this near relative 

 continues for only 4 or 5 hours. The duration of copula- 

 tion of the 18 pairs was as follows : 



Hours in copulo No. of pairs 



Less than 1 hour 2 



1 to 2 hours 2 



2 to 3 hours 



3 to 4 hours 4 



4 to 5 hours 9 



5 to 6 hours 1 



