Schedule III. Hyalella. 

 One pair produces an average of 18 eggs 15 times in 152 days 

 Generation I. 



Brood 1. 9 prs. ave., 14 eggs on 43d day and 10 times thereafter 



Generation II. 



270 



1386 



588 



180 



108 



36 



462 



90 



30 



